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UNIVERSIDADE CIDADE DE SÃO PAULO
PROGRAMA DE MESTRADO E DOUTORADO EM FISIOTERAPIA
MARIA LUIZA CAIRES COMPER
EFEITOS DO RODÍZIO DE FUNÇÕES NA PREVENÇÃO DE
DISTÚRBIOS OSTEOMUSCULARES RELACIONADOS AO
TRABALHO
São Paulo
2015
MARIA LUIZA CAIRES COMPER
EFEITOS DO RODÍZIO DE FUNÇÕES NA PREVENÇÃO DE
DISTÚRBIOS OSTEOMUSCULARES RELACIONADOS AO
TRABALHO
Tese de Doutorado apresentada ao
Programa de Mestrado e Doutorado em
Fisioterapia da Universidade da Cidade
de São Paulo, como requisito para
obtenção do título de Doutora, sob a
orientação da professora Dra. Rosimeire
Padula.
São Paulo
2015
MARIA LUIZA CAIRES COMPER
EFEITOS DO RODÍZIO DE FUNÇÕES NA PREVENÇÃO DE DISTÚRBIOS
OSTEOMUSCULARES RELACIONADOS AO TRABALHO
Área de concentração: Avaliação, Intervenção e Prevenção em Fisioterapia
Data da Defesa: 17 de Dezembro de 2015
Resultado: ____________________________
BANCA EXAMINADORA:
Profª. Dra. Luciana Dias Chiavegato _________________________________________
Universidade Cidade de São Paulo
Prof. Dr. Leonardo Oliveira Pena Costa_______________________________________
Universidade Cidade de São Paulo
Prof. Dr. Tabajara de Oliveira Gonzalez_______________________________________
Universidade Nove de Julho
Profª. Dra. Tatiana de Oliveira Sato___________________________________________
Universidade Federal de São Carlos
Profª. Dra. Rosimeire Simprini Padula ________________________________________
Universidade Cidade de São Paulo
iii
“Eu sei o preço do sucesso: dedicação, trabalho
duro e uma incessante devoção às coisas que você quer ver
acontecer”.
Frank Lloyde Wright
iv
DEDICATÓRIA
Dedico este trabalho aos maiores amores de minha vida!
Aos meus pais, José Luiz e Maria da Conceição, por me presentearem com a vida,
com o amor incondicional e com seus melhores gestos e palavras. O que seria de mim sem
vocês?
Ao meu marido, Aleçandro, e meus filhos: Letícia, Laura e Luiz Heitor. Vocês são a
minha razão de viver! Para vocês, eu sempre darei o meu melhor!
v
AGRADECIMENTOS
Este trabalho constitui o resultado de uma trajetória que teve inicio em 2010, quando
motivada pela necessidade de melhorar minha formação acadêmica, aumentar a produção
científica e aprofundar meus conhecimentos na área de atuação profissional, eu decidi
participar do processo seletivo para o Programa de mestrado em Fisioterapia da
Universidade Cidade de São Paulo. Não tenho dúvidas de que foi uma das decisões mais
acertadas que já tive na vida, pois durante esta trajetória eu pude aprender com os
melhores professores que poderia ter e conviver com colegas de diferentes regiões deste
imenso país. Em especial, não posso deixar de falar de minha orientadora, Profa. Dra.
Rosimeire Simprini Padula, que é uma destas pessoas raras. Ela acredita no melhor das
pessoas e se doa, sem medir esforços para que elas alcancem o sucesso. Com ela eu
aprendi tanto e sobre tanta coisa relacionada a pesquisa e tanto e muito mais sobre como
ser uma pessoa melhor e não desistir nunca. É impossível mensurar o quanto tenho em
mim por influência dela e o quanto sou grata por isso!
Durante estes 5 anos, eu vivenciei um período de grande amadurecimento
pessoal e profissional. Tive a oportunidade de: participar e apresentar trabalhos em
eventos nacionais e internacionais, publicar artigos científicos em revistas de grande
impacto para a Fisioterapia, ter um trabalho, selecionado como um dos 8 melhores
resumos do Congresso Brasileiro de Fisioterapia (2011), ter um projeto financiado pelo
CNPQ. Mas muito mais que isso, eu tive a oportunidade de compartilhar o conhecimento
adquirido com os alunos para os quais tive a oportunidade de ensinar, contruindo para
uma formação voltada para uma prática baseada em evidência.
Mas tudo isso só foi possível porque tenho em minha vida muito anjos colocados
em minha vida por Deus para que Seus planos e os meus sonhos pudessem ser
cumpridos! Eles ficaram atrás dos bastidores me oferecendo todo tipo de suporte e apoio
necessário. Eu sinceramente não tenho palavras para agrader tudo o que fizeram e fazem
por mim! Muito, muito,...,(mais um milhão de muito) obrigada a você:
Aleçandro Dias Gomes, por me motivar, apoiar e me fazer enxergar as coisas de
uma forma mais prática. Você é meu amor, melhor amigo e exemplo de pessoa;
Leticia, Laura e Luiz Heitor, por me permitir conviver com vocês e por me doar este
amor, carinho e ternura sem limites! Obrigada por entenderem todos os momentos em que a
vi
mamãe teve que se ausentar. É por vocês que eu consegui forças para sempre seguir lutando
em busca do melhor para a nossa família.
José Luiz Comper e Maria da Conceição Caires Silva Comper, por serem os maiores
torcedores do meu sucesso e por isso, fazer o (im)possível para que ele pudesse ser alcançado.
Mãe, você é meu exemplo de vida e de superação. Pai, você é meu meu exemplo de
humildade e simplicidade. E juntos vocês são meu conforto, porto seguro e os melhores pais
do mundo.
Rosimeire Simprini Padula, pois sem você o aprendizado não teria sido o mesmo.
Obrigada pela paciência, compreenssão, dedicação e por sempre acreditar em mim.
Gabriela dos Santos Evangelista (meu braço direito), por tudo o que fez e faz por
mim. Você é simplesmente incrível: é dedicada, esforçada, competente e muito mais.
Não tenho palavras para agredecer. Obrigada por todo o suporte de sempre e, especialmente,
pelo seu auxílio nas atividades da empresa e do projeto de pesquisa;
Klênia Solis Carrazza (meu braço esquerdo), por ter assumido minhas atividades da
coordenação nos períodos mais críticos e necessários. Também não tenho palavras para te
agradecer. Obrigada por compartilhar comigo sua sabedoria e amizade.
Trifil (Gestores e Trabalhadores da empresa), por terem me dado a oportunidade de
realizar este projeto de pesquisa. Sem vocês esta trajetória não teria sido possível.
Renata Gonçalves Dantas, por compartilhar comigo sua amizade, seus conselhos e
desesperos também. Obrigada pelos dias e noites de trabalho duro compartilhados ao longo
destes anos, pelas viagens de estudo e por todos os nossos momentos de conversa sem cunho
científico. Ah! E porque não agardecer pelo serviço de baby sister nos momentos necessários.
Luiz Alfredo Omena, Ana Lúcia Bonfim e Odília Moliterni, por sempre terem
permitido que eu me ausentasse de minhas tarefas na universidade em busca de uma maior
qualificação profissional.
Adson Victor, Caique Simões e Roberto Paes, vocês foram incríveis por abrir mão das
férias para me auxiliar na tabulação dos dados. Sou muito grata por isso.
D. Rosi, D. Marineide e D. Eliete, no dia-a-dia e durante as minhas ausências,
vocês conseguiram cuidar de minhas crianças e casa, oferecendo todo o apoio afetivo e
cuidado necessário.
Todos aqueles outros anjos, por permitirem, diretamente e indiretamente, que este
trabalho pudesse ser concluído.
vii
Por fim, agradeço a meu Deus maravilhoso e perfeito, por estar presente em minha
vida durante esta caminhada; por cuidar de mim; e, por possibilitar que meus sonhos se
realizassem da melhor forma. Senhor, Graças a Louvores rendo a ti por tudo isso!
Maria Luiza Caires Comper
viii
PREFÁCIO
Esta tese de doutorado aborda temas relacionados ao rodízio de função enquanto
estratégia de prevenção dos distúrbios musculoesqueléticos e controle dos fatores de risco
biomecânicos em trabalhadores da indústria de manufatura. Está apresentada no formato
híbrido, como proposto pelo Programa de Mestrado e Doutorado em Fisioterapia da
Universidade Cidade de São Paulo, que permite a inclusão de artigos publicados, aceitos,
submetidos ou em preparação para publicação no corpo do texto da tese. É constituída por 6
capítulos, sendo que cada um deles apresenta a sua própria lista de referências bibliográficas e
de materiais complementares.
O capítulo 1 apresenta uma contextualização de temas relevantes que permitem ampla
abordagem sobre rodízio de função, tais como: origem, conceitos, teorias, objetivos da
adoção, critérios para organização, etapas de implantação e evidências científicas relacionadas
à sua efetividade enquanto estratégia de prevenção dos distúrbios musculoesqueléticos e
controle dos fatores de risco biomecânicos em trabalhadores da indústria de manufatura. Este
capítulo também inclui os objetivos e a justificativa do estudo.
O capítulo 2 apresenta o artigo “The effectiveness of job rotation to prevent work-
related musculoskeletal disorders: protocol of a cluster randomized clinical trial”,
publicado no periódico BMC Musculoskeletal Disorders, em 22 de maio de 2014. O objetivo
deste capítulo foi descrever, em maiores detalhes, os métodos de pesquisa do ensaio clínico
controlado e randomizado por cluster.
O capítulo 3 apresenta o artigo denominado “Job Rotation Designed to
Musculoskeletal Risk Control and Disorders in Manufacturing Industries: A Systematic
Review”. Este capítulo tem como objetivo revisar sistematicamente as evidências atuais sobre
efetividade e estratégias de implantação do rodízio de função como estratégia de controle de
risco e doenças em indústrias de manufaturas. Esta formatado de acordo com as normas do
periódico Applied Ergonomics, para o qual o artigo sera submetido. As normas de publicação
desse periódico podem ser encontradas ao final do texto, anexo a essa tese.
O capítulo 4 apresenta o artigo denominado “The Effectiveness of Job Rotation to
Prevent and Control Work-Related Musculoskeletal Disorders: A Cluster Randomized
Clinical Trial”. Este capítulo tem como objetivo apresentar os resultados obtidos por meio
do ensaio clínico randomizado por cluster, que avaliou a efetividade do rodízio de função
ix
como estratégia de prevenção e controle dos distúrbios musculoesqueléticos relacionados ao
trabalho. O artigo esta formatado de acordo com as normas do periódico The Journal of the
American Medical Association (JAMA), para o qual o artigo sera submetido. As normas de
publicação desse periódico podem ser encontradas ao final do texto, anexo a essa tese.
O capítulo 5 apresenta a descrição das etapas de implantação do projeto de pesquisa e
das barreiras encontradas. Também apresenta uma sucinta discussão das lições aprendidas no
decorrer da pesquisa. Pretende-se que estas informações possam ser usadas para a escrita de
um artigo de opinião sobre as principais barreiras e lições aprendidas durante a implantação
de um programa de rodízio de função.
O capítulo 6 apresenta as considerações finais da tese, bem como perspectivas de
estudos futuros sobre o tópico. Este capítulo também apresenta um contexto histórico de
apresentações de trabalho em congressos e desenvolvimento de pesquisas de iniciação
cientifica desenvolvidas em consonância com o presente estudo.
Em relação aos aspectos éticos e de registro, o projeto de pesquisa “The effectiveness
of job rotation to prevent work-related musculoskeletal disorders: a cluster randomized
clinical trial” foi aprovado pelo Comitê de Ética em Pesquisa da Universidade Cidade de São
Paulo (protocolo nº 18170313.5.0000.0064) e foi prospectivamente registrado no
ClinicalTrials.gov (NCT01979731). O projeto foi financiado pelo Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq ) (473651 / 2013-0).
A revisão sistemática foi registrada no International Prospective Register of
Systematic Reviews–PROSPERO (CRD42014013319). A realização deste estudo de revisão
e a formulação de uma nova equação para auxiliar no planejamento das escalas de rodízio,
que também fazem parte do estágio de pós-doutorado da profa. Dra. Rosimeire Simprini
Padula, em Boston, Massachussets, EUA, teve suporte de financiamento do CNPq
(249621/2013-4).
x
RESUMO
Contextualização: O rodízio de funções é uma estratégia ergonômica organizacional,
frequentemente utilizada em linhas de produção industrial. Ele é usado para aumentar o
desempenho, autonomia e flexibilidade dos trabalhadores e reduzir a exposição contínua aos
fatores de risco para doenças músculo-esqueléticas. Contudo, a eficácia do rodízio como
estratégia de prevenção e controle de distúrbios osteomusculares não possui sustentação
científica adequada.
Objetivos: Avaliar a efetividade do rodízio de função como estratégia de prevenção de
prevenção dos distúrbios musculoesqueléticos e controle dos fatores de risco biomecânicos
em trabalhadores da indústria de manufatura, e, sintetizar evidências relacionadas a
efetividade do rodízio de função e aos parâmetros utilizados para organizar as escalas de
rodízio nas indústrias de manufatura.
Métodos: Trata-se de uma revisão sistematica e um estudo controlado, randomizado por
cluster. Para a revisão, realizou-se buscas sistematizadas nas bases de dados: Medline,
Embase, ISI Web of Knowledge, CINAHL, Psyinfo, Scopus e SciELO. Os artigos localizados
foram avaliados por dois avaliadores independentes, que extraíram os dados para análise e
tabulação. O ensaio clínico foi realizado em que 4 setores de produção (957 trabalhadores)
uma indústria têxtil, randomicamente divididos entre o grupo de intervenção e o grupo
controle. O grupo intervenção realizou rodízio de função e orientações ergonômicas. O grupo
controle recebeu apenas as orientações ergonômicas. O desfecho primário foi o número de
horas de trabalho perdidas por afastamento do trabalho por licença médica decorrente de
doença do sistema osteomuscular e do tecido conjuntivo, mensurado em quatro intervalos de
três meses. Os desfechos secundários foram mensurados antes e após a intervenção e incluiu:
sintomas musculoesqueléticos, fatores de risco para a ocorrência dor musculoesquelética,
fatores de risco psicossociais e fadiga, estado geral de saúde, produtividade e custos. Os
efeitos da intervenção foram calculados usando modelos lineares mistos, seguindo os
princípios de intenção de tratamento.
Resultados: Quinze estudos foram incluídos na revisão sistemática. Foram identificados dois
estudos com boa qualidade metodológica, que tiveram resultados conflitantes, por serem
fortemente influenciados pelos modelos de produção, organização e execução do rodízio de
xi
função. Os paramêtros descritos para criação das escalas de rodízio possuem grande
variabilidade, mas na maioria dos estudos, os fatores biomecânicos e organizacionais foram
os mais utilizados. Contudo, houve semelhança nos intervalos de alternância, que tende a
variar entre uma ou duas horas. Em relação ao ensaio clínico, a amostra final incluiu 2
departamentos no grupo de intervenção (N = 266) e 2 departamentos no grupo controle (N =
255). Após 12 meses, o programa de de rodízio de função não promoveu efeitos significativos
no número de horas de trabalho perdidas em razão de licença médica por distúrbios
músculoesqueléticas. Não houve diferença em favor do grupo de intervenção (M -5.6 horas,
95% IC -25,0 para 13,8). Também não houve diferenças entre os grupos para os desfechos
secundários (P> 0,05).
Conclusão: Os resultados gerais da revisão sistemática sugerem a evidência do rodízio como
estratégia para prevenção e controle de distúrbios osteomusculares é bastante limitada,
principalmente em razão da qualidade metodológica dos estudos e da ausência de ensaios
controlados randomizados. O grupo rodízio não foi mais eficaz do que o grupo controle na
prevenção de distúrbios osteomusculares em trabalhadores industriais para diminuir o número
de horas de trabalho perdidas devido a doença ou sintoma osteomuscular e para prevenir e
controlar doenças músculo-esqueléticas.
Palavras-chave: Rodízio de função, Ergonomia, Indústria, Absenteismo, Distúrbios
Musculoesqueléticos
xii
ABSTRACT
Background: Several reasons justify the use of job rotation as an organizational strategy for
industrial production lines. It is used for increasing performance, autonomy and flexibility of
workers and alternate continuous exposure to risk factors for musculoskeletal disorders.
However, the effectiveness of job rotation to prevent and control musculoskeletal complaints
has limited evidence.
Objective: To assess the job rotation effectiveness as a strategy for the prevention of
musculoskeletal disorders and control of biomechanical risk factors in manufacturing
industrial workers, and synthesize evidence regarding the job rotation effectiveness and the
parameters used to organize job rottaion scales in manufacturing industries.
Studies Design: These are a systematic review and a cluster randomized controlled trial. To
review, systematic searches were conducted in the electronic databases: Medline, Embase, ISI
Web of Knowledge, CINAHL, Psyinfo, Scopus and SciELO. Two independent evaluators,
who extracted the data for analysis and tabulation, assessed the papers. The clinical trial was
performed in which 4 production sectors (957 employees) a textile industry, randomly divided
between the intervention group and the control group. The intervention group performed job
rotation and ergonomic guidelines. The control group only received ergonomic guidelines.
The primary outcome measure was absence from work due to sick leave measure in 3-months
follow-up. Secondary outcomes were measured at baseline and 12-month follow-up and
included: musculoskeletal symptoms, job factors for musculoskeletal pain and disorders,
psychosocial factors and fatigue, and general health and productivity. The effects of the
intervention were calculated using linear mixed models following intention-to-treat principles.
Results: Fifteen studies were included in the systematic review. Two studies of good
methodological quality were identified and showed conflicting results, because they are
strongly influenced by models of production, organization and execution of the job rotation.
The parameters described for creating the rotation schedules have greater variability, but in
most studies, biomechanical and organizational factors were the most used. However, there
was a similarity in rotation intervals, which varies between one to two hours. Regarding the
clinical trial, the final sample included 2 departments into intervention group (N=266) and 2
into control group (N=255). After 12 months, the job rotation program did not significantly
xiii
change its effect on number of working hours lost due to the sick leave caused by
musculoskeletal injury. There was no difference in favor of the intervention group (MD -5.6
hours, 95% CI -25.0 to 13.8) at 12-month follow-up. There were also no differences between
groups for the secondary outcomes (P > 0.05).
Conclusion: Overall results of the systematic review suggest that there is no evidence of job
rotation as a strategy for prevention and control of musculoskeletal disorders, mainly due to
the methodological quality of the studies and the absence of randomized controlled trials. The
job rotation program was no more effective than the control group in preventing
musculoskeletal disorders in industrial workers for decreasing the number of working hours
lost due to musculoskeletal symptom or disease and to prevent and control musculoskeletal
disorders.
Keywords: Job rotation, Ergonomic, Industry, Absenteeism, Musculoskeletal Disorders
xiv
SUMÁRIO
Prefácio ................................................................................................................................... viii
Resumo ...................................................................................................................................... x
Abstract .................................................................................................................................... xi
Capítulo 1 ................................................................................................................................ 15
Contextualização ................................................................................................................... 15
Objetivos da Tese .................................................................................................................. 21
Referências ............................................................................................................................ 22
Capítulo 2 ................................................................................................................................ 27
Artigo 1: The effectiveness of job rotation to prevent work-related musculoskeletal
disorders: protocol of a cluster randomized clinical trial .................................................... 27
Capítulo 3 ................................................................................................................................ 34
Artigo 2: Job Rotation Designed to Musculoskeletal Risk Control and Disorders in
Manufacturing Industries: A Systematic Review .................................................................. 34
Capítulo 4 ................................................................................................................................ 86
Artigo 3: The Effectiveness of Job Rotation to Prevent and Control Work-Related
Musculoskeletal Disorders: A Cluster Randomized Clinical Trial ...................................... 86
Capítulo 5 .............................................................................................................................. 113
Desdobramentos do Estudo – Lições Aprendidas .............................................................. 113
Execução do Projeto de Pesquisa ........................................................................................ 113
Lições Aprendidas ............................................................................................................. 115
Referências .......................................................................................................................... 116
Capítulo 5 .............................................................................................................................. 117
Considerações Finais .......................................................................................................... 117
Idealização da Revisão Sistemática, Conclusões e Desdobramentos ................................. 117
Idealização do Ensaio Clínico, Conclusões e Desdobramentos .......................................... 119
Referências .......................................................................................................................... 120
Anexos e Apêndices
15
CAPÍTULO 1
Contextualização
Os trabalhos nas indústrias de manufatura são organizados mediante o planejamento e
a gestão da produção que deve atender aos requisitos técnicos e de capacitação do
trabalhador1. Para tanto, as indústrias utilizam os princípios de produção Taylorista, Fordista
e, mais atualmente o Sistema Toyota de Produção ou Lean Production1,2
, que objetivam
melhorar a performance e eficiência do trabalhador, com economia de tempo e custos2. Estes
princípios são caracterizados, respectivamente, pelo (1) fracionamento e especialização de
tarefas, (2) redução dos movimentos desnecessários e intensificação do trabalho por meio de
linhas de montagem móvel, e, (3) flexibilização de produtos e mão de obra com alto controle
de qualidade e eliminação de desperdícios1, 2
. Isto faz com que a maior parte das operações
produtivas sejam caracterizadas por tarefas padronizadas, repetitivas e com curtos ciclos de
tempo3. Estas características, associadas à presença fatores de risco físicos (movimentos
repetitivos; força excessiva; postura inadequada, estática e/ou prolongada, vibração, e,
compressão tecidual), organizacionais (excesso de jornada de trabalho; ausência de intervalos
e pausas) e cognitivos (complexidade da tarefa, decisões complexas, altas demandas
psicológicas, concentração, atenção) podem contribuir para o surgimento de distúrbios
musculoesqueléticos relacionados ao trabalho3-5
.
Os distúrbios osteomusculares relacionados ao trabalho (DORT) são definidos como
uma síndrome clínica relacionada ao trabalho, caracterizada pela ocorrência de diversos
sintomas musculares, concomitantes ou não, que resultam em incapacidade funcional,
temporária ou permanente6. Estes distúrbios incluem uma variedade de condições
inflamatórias e degenerativas que afetam músculos, tendões, ligamentos, articulações e nervos
periféricos e podem comprometer a coluna, pescoço, ombros, cotovelos, antebraços, punhos e
mãos3. A fisiopatologia da DORT pode ser explicada pelo modelo conceitual proposto por
Armstrong (1993)7. De acordo com este modelo, a DORT resulta da deficiente capacidade
biológica natural de recuperação do tecido frente às alterações fisiológicas inflamatórias
mantidas por um longo período de tempo7. Em outras palavras, a DORT se manifesta quando
não há tempo suficiente para a regeneração tecidual completa.
No cenário industrial, a DORT representa um grande problema econômico por afetar a
produtividade e qualidade da produção e aumentar os custos diretos e indiretos causados pelos
16
dias de trabalho perdidos8,9
. Estima-se que, somente no ano de 2012, os EUA desembolsaram
227 bilhões para reduzir as perdas de produtividade decorrente dos dias de trabalho perdidos
por doenças, incluindo as DORT9. Diante deste cenário, torna-se imperativo a realização de
intervenções efetivas que favoreçam a prevenção dos distúrbios musculoesqueléticos e
controle dos fatores de risco ocupacionais10. Dentre as intervenções mais recomendadas estão:
o redesenho de postos de trabalho, adequação de mobiliários, máquinas e ferramentas,
orientações ergonômicas, pausas para descanso e rodízio de funções3.
O rodízio de funções é uma das intervenções organizacionais mais praticadas nas
indústrias de manufatura11-14
, tendo origem nas indústrias japonesas, no final dos anos 5015
.
Nos EUA, o interesse pelo rodízio ocorreu nos anos 80, quando engenheiros e gestores
passaram a adotá-lo como uma alternativa para aumentar a performance, flexibilidade e
autonomia dos trabalhadores industriais, reduzindo assim, os custos de produção13,16-20
. Os
efeitos positivos do rodízio, do ponto de vista dos gestores, foram tantos que, no ano de 1992,
26% das indústrias americanas realizavam rodízio de tarefas com mais da metade de seus
funcionários21
. Em 2007, esse número praticamente dobrou, uma vez que 42,7% das
indústrias localizadas no centro-oeste dos Estados Unidos adotavam alguma forma de
rodízio22
.
Existem três principais teorias que tentam explicar o motivo da grande adesão ao
rodízio de função pelas indústrias em geral. São elas: Teoria da aprendizagem do
trabalhador; Teoria da aprendizagem do empregador e Teoria da motivação23
. A primeira
teoria está fundamentada no fato de que, ao realizar o rodízio, o trabalhador é exposto a
tarefas que requerem diferentes competências e habilidades24
. Isso faz com que ele adquira
novos conhecimentos e experiências25
, tenha uma compreensão mais profunda do processo
produtivo e seja flexível para alocação em diferentes tarefas, a critério da necessidade de
produção23
. A teoria da aprendizagem do empregador defende a ideia de que o rodízio fornece
informações sobre as habilidades do trabalhador, uma vez que seu desempenho pode ser
observado em cada uma das tarefas por onde ele passa23
. Por fim, a teoria da motivação tem
como prerrogativa o fato de que o rodízio torna o trabalho mais interessante23
. Contudo,
nenhuma das teorias defende o uso do rodízio como estratégia de prevenção e controle dos
distúrbios osteomusculares. O que pode estar relacionado ao fato de que o rodízio teve origem
a partir da necessidade de reduzir custos e flexibilizar a produção13,16,20
.
Com o passar do tempo, além de atender as necessidades de gerenciamento da
produção, o rodízio passou a ser adotado como uma estratégia de prevenção dos distúrbios
17
musculoesqueléticos e controle dos fatores de risco biomecânicos, inclusive com suporte
técnico de agências federais de saúde e segurança, como a OSHA, NIOSH e, no Brasil, a
Norma Regulamentadora nº 17 (NR-17) 26,27
indica a necessidade de revezamento das
posturas de trabalho, de modo a que o trabalho se adeque as caracteristicas psicofisiológicas
dos trabalhadores, sendo o rodizio de função entendido como tal. A premissa é de que, ao
alternar entre tarefas de maior e menor risco, o rodízio reduz a sobrecarga biomecânica
acumulada em uma parte específica do corpo28
. Isso porque, a alternância da exposição
possibilita a recuperação de um grupo muscular enquanto outros grupos estão sendo
solicitados3,29
. Neste caso, o rodízio deveria ser recomendado para tarefas repetitivas, estáticas
ou monótonas3, de manuseio e transporte de carga
29 ou que possua posturas inadequadas e
estáticas30,31
. Ele poderia ser usado para aliviar os efeitos da sobrecarga muscular, monotonia
e estresse32
, reduzir o absenteísmo33,34
, favorecer a inclusão de trabalhadores com
incapacidade temporária ou permanente18
, e aumentar a satisfação do trabalhador35
.
A variedade de propósitos do rodízio pode explicar o grande número de termos
empregados e conceitos utilizados para defini-lo. Rodízio de tarefas, rodízio de funções,
rodízio de posições e trabalhadores multifuncionais são alguns dos termos encontrados nos
artigos que descrevem o rodízio de função36
. Em termos conceituais, o rodízio de funções
pode ser definido sob dois pontos de vista. Em relação ao gerenciamento/produção, Jorgensen
et al.22
e Huang24
definem o rodízio de funções como um sistema de trabalho que permite aos
trabalhadores alternar entre tarefas que solicitam diferentes habilidades e responsabilidades. É
uma forma de possibilitar uma formação complementar para os trabalhadores, o que permite
que adquiram novos conhecimentos e experiências em tarefas e/ou setores diferentes25
. Do
ponto de vista de prevenção dos distúrbios musculoesqueléticos, o rodízio é definido como a
alternância entre diferentes níveis de exposição ao risco biomecânico ou de demandas
físicas22,37
. Atualmente, estes dois conceitos têm sido integrados, de modo a possibilitar que o
rodízio promova os efeitos positivos para a indústria e para os trabalhadores.
Apesar de todas as vantagens já apresentadas, na prática, o rodízio de funções não é
tão simples de ser implantado nas indústrias. Algumas são as razões para que isto aconteça,
tais como as determinações da legislação brasileira, por meio da Consolidação das Leis do
Trabalho (CLT) 38
, que diz que a troca entre diferentes funções só pode ocorrer se for para
cargos mais elevados. Isto dificulta rodízio de trabalhadores entre setores e entre tarefas de
diferentes graus de complexidades39
. Segundo, porque a implantação da proposta (ideal)
planejada, muitas vezes, esbarra nas características da tarefa, organização do trabalho, espaço
18
físico e número de trabalhadores. Por fim, porque a execução do rodízio dependerá da
convicção dos gestores sobre a importância desta estratégia e da aceitação dos trabalhadores
em realizá-la39
.
A implantação de um programa de rodízio deve cumprir algumas etapas, que incluem:
(1) identificação das possíveis tarefas para realização do rodízio; (2) análise dos níveis de
complexidade destas tarefas e das competências e habilidades necessárias para realizá-las; (3)
análise das demandas e nível de risco biomecânico; (4) planejamento da escala de rodízio,
incluindo a sequência e frequência; (5) treinamento dos trabalhadores; e, (6) implantação e
acompanhamento.
As etapas de identificação e análise das tarefas à serem incluídas no programa de
rodízio são de grande importância, já que fornecem as informações necessárias para que a
alternância entre os níveis de exposição e a redução do estresse físico e cognitivo sejam
efetivos. Dentre as informações a serem analisadas, estão: número de trabalhadores e de
tarefas envolvidas, habilidades e competências necessária para execução da tarefa, nível de
exposição, região corporal solicitada, frequência de movimentos, duração da exposição,
micropausas, duração, dentre outros12,22,40
. As habilidades e competências dos trabalhadores
podem ser calculadas por meio de curvas de aprendizado39
, enquanto os aspectos
biomecânicos podem ser avaliados por meio dos métodos de análise do risco ergonômico, tais
como: Quick Exposure Check (QEC)41
, Rapid Entire Body Assessment (REBA)36
, Rapid
Upper Limb Assessment (RULA)37
, etc.
O planejamento do rodízio é determinado baseando-se nas informações coletadas
anteriormente e nos seguintes critérios: (1) principal demanda física (manuseio de materiais,
repetição de movimentos, postura estática); (2) postura predominantemente adotada para a
realização da tarefa (sentada, ajoelhada, em pé, andando); (3) regiões corporais de maior
sobrecarga (ombros, cotovelos, punhos, mãos, coluna); e, (4) nível de intensidade da
exposição (baixo, moderado, alto ou muito alto). A autonomia do trabalho (técnicas e ritmo
de trabalho) e o uso de máquinas e ferramentas também devem ser avaliados42
. É importante
destacar que, nas situações em que o rodízio for proposto com o objetivo de modificar os
padrões de exposição ergonômica, os trabalhadores deverão realizar alternância entre tarefas
de baixo, moderado e alto risco ergonômico e com diferentes solicitações biomecânicas por
região corporal22,37
. O planejamento inadequado do programa de rodízio não só torna a
19
intervenção ineficaz, como pode resultar em aumento dos níveis de exposição para os
trabalhadores43
.
A etapa seguinte, compreende a organização da sequência de tarefas a serem
alternadas. Para auxiliar nesta organização, alguns métodos e algoritmos foram desenvolvidos
para gerar escalas de alternância entre as tarefas a partir de diferentes critérios e
parâmetros11,12,18,30,32,44,45
. Um dos primeiros algoritmos foi desenvolvido por Carnahan et
al.46
para tarefas de manuseio de materiais e incluiu o Job Severity Index (JSI). Este índice
integra critérios de percepção do trabalhador sobre a capacidade de realizar atividades de
levantamento/manuseio de materiais para avaliar o potencial de risco de lesão em coluna
vertebral. Seguindo uma proposta parecida, Tharmmaphornphilas e Normam45
propuseram
um método heurístico mais robusto, que considerou como parâmetros o JSI e o número de
dias perdidos em razão de lesões em coluna lombar. Posteriormente, os algoritmos passaram a
incluir um maior número de parâmetros, que variam a depender da proposta do rodízio. Por
exemplo, Diego-Mas et al. (2009)40
construíram um algoritmo para prevenir a acumulação de
fadiga decorrente da repetição de movimentos. Este algoritmo incluiu parâmetros
biomecânicos (postura no trabalho, frequência e duração dos movimentos realizados);
organizacionais (capacidades gerais para a realização do trabalho, como dirigir, escrever,
falar, utilizar computador); cognitivos (tomada de decisões, autonomia, demandas cognitivas);
e, outros (aspectos ambientais e de segurança). De modo similar, outros algoritmos foram
propostos com o objetivo de reduzir os efeitos da repetitividade e fadiga11,47-49, e equilibrar os
efeitos do rodízio frente ao tédio/motivação do trabalhador em células de manufatura e
favorecer a aprendizagem de habilidades do trabalhador32
. É importante destacar que, apesar
de serem muitos, nenhum destes algoritmos foi avaliado em ensaios clínicos.
Sequencialmente, os trabalhadores devem ser treinados para a realização das tarefas
incluídas no programa de rodízio. Esta etapa é importante para que os trabalhadores tenham o
conhecimento e desenvolvam as competências e habilidades necessárias para lidar com todas
as etapas das tarefas produtivas, bem como garantir a qualidade dos processos e produtos
envolvidos nestas23
. A ausência de treinamento pode ser crítica para resultados positivos do
rodízio, uma vez que é preciso que o trabalhador compreenda o uso desta intervenção e
permita que novas competências sejam adquiridas50
. Além disso, a falta de treinamento
implica em redução da produtividade, aumento de custos por retrabalho e baixa qualidade dos
produtos39
; e, pode resultar em aumento das queixas musculoesqueléticas
51.
20
Diante do exposto, percebe-se que o rodízio de função: (1) pode contribuir para a
prevenção de distúrbios musculoesqueléticos e controle dos fatores de risco biomecânicos; (2)
possui uma metodologia própria, com etapas e parâmetros de planejamento e implantação; e,
(3) ultimamente, tem sido bastante utilizado nas indústrias de manufatura como estratégia de
controle de distúrbios musculoesqueléticos. Contudo, ainda existem várias lacunas científicas
que sustentem o uso desta intervenção. Primeiro, os estudos, em geral, não possuem qualidade
metodológica apropriada para avaliar a efetividade do rodízio, uma vez que a maior parte dos
estudos são transversais11,12,18,30,32,43-45,52,53 e nenhum estudo controlado randomizado foi
realizado até o momento. Segundo, a maioria dos estudos têm avaliado os efeitos do rodízio
em estudos retrospectivos em que esta intervenção foi adotada para atender as necessidades
de produção39,54. Neste caso, o programa de rodízio pode não ter sido adequadamente
planejado para que o nível de exposição ao risco biomecânico ocorresse. Aliás, a descrição
dos parâmetros utilizados como critério para definição da escala de rodízio representa outro
problema
Todas estas razões contribuem os recentes achados de uma revisão sistemática36
sobre
efeitos do rodízio de função sobre queixas musculoesqueléticas e parâmetros para
sustentabilidade de vida laboral foi publicada36
. Os autores concluíram que os resultados dos
16 estudos incluídos na revisão são conflitantes e inconsistentes36
. Isto porque existem alguns
estudos que mostram efetividade do rodízio de função para a prevenção dos distúrbios
musculoesqueléticos, enquanto outros não. Por exemplo, o estudo de Roquelaure et al.54
avaliou, por meio de um caso-controle, a associação entre os fatores organizacionais e
síndrome do túnel do carpo em três indústrias. Os resultados mostraram que, quando as
características individuais e relacionadas com o trabalho são controladas, a ausência do
rodízio está associada a 6,3 vezes maior chance de desenvolver a síndrome do túnel do carpo.
Kuijer et al. 53
, ao comparar grupos que realizavam ou não rodízio em um estudo transversal,
também encontraram reduções significativas da sobrecarga física em trabalhadores de um
departamento de coleta de lixo que realizaram rodízio entre a tarefa de dirigir e coletar lixo.
No entanto, ao realizarem em um estudo longitudinal, prospectivo, Kuijer et al. (2005)55
observaram que, a longo prazo, o rodízio aumentou a sobrecarga em outras regiões corporais
e, que os trabalhadores começaram a relatar mais dores lombares, principalmente para o
grupo que apenas dirigia. Este grupo manteve a exposição aos mesmos fatores de risco,
mesmo com a alternância das tarefas. Resultados similares foram obtidos por Frazer et al.43
,
que avaliou duas tarefas de manuseio de materiais, uma com baixo nível de sobrecarga e outra
com alto nível. O risco de dor lombar aumentou à medida que maior quantidade de tempo foi
21
empregada para realização da tarefa de maior sobrecarga, em razão dos efeitos cumulativos e
de pico de força43
. O estudo de Guimarães et al.39
avaliou a aquisição de competências por
parte dos trabalhadores em rodízio e os efeitos de rotação de empregos avaliados após 3,5
anos. Os resultados indicaram que não houve diferenças entre o aprendizado e a performance
entre os trabalhadores que realizavam e não realizavam rodízio. Além disso, houve redução
na ocorrência de acidentes e absenteísmo, melhora da produtividade e retrabalho, e maior
satisfação do trabalho para os trabalhadores que realizavam o rodízio.
Diante do exposto, verifica-se a real necessidade de estudos, de alta qualidade
metodológica que avaliem a efetividade do rodízio de função como estratégia de prevenção
para os distúrbios musculoesqueléticos. Assim, até o presente momento, as propostas deste
estudo são: revisar sistematicamente as evidências atuais sobre efetividade e estratégias de
implantação do rodízio de função como estratégia de controle de risco e doenças em
indústrias de manufaturas; e, avaliar o efeito do rodízio de funções na prevenção dos
distúrbios osteomusculares em trabalhadores industriais, por meio de um estudo clinico
controlado e randomizado por cluster. Este efeito será avaliado por meio da quantidade de
horas de trabalho perdidos em razão do afastamento por licença médica. A hipótese é de que o
grupo que realiza o rodízio tenha menor quantidade de horas perdidas por afastamento de
licença médica. Outros estudos relacionados ao planejamento do rodízio de função estão
sendo realizados.
Objetivos da tese:
Avaliar, por meio de uma revisão sistemática, a eficácia do rodízio como estratégia de
controle de risco e doenças e identificar os parâmetros utilizados para organizar as
escalas de rodízio nas indústrias de manufatura.
Avaliar, o efeito do rodízio de função na prevenção dos distúrbios
musculoesqueléticos em trabalhadores industriais, por meio de um estudo controlado e
randomizado por cluster.
22
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27
CAPÍTULO 2
ARTIGO 1
The effectiveness of job rotation to prevent work-related
musculoskeletal disorders: protocol of a cluster randomized
clinical trial
Publicado na revista: BMC Musculoskeletal Disorders
Comper MLC, Padula RS. The effectiveness of job rotation to prevent work-related musculoskeletal
disorders: Protocol of a cluster randomized clinical trial. BMC Musculoskeletal Disorders. 2014;15
28
29
30
31
32
33
34
CAPÍTULO 3
ARTIGO 2
Job Rotation Designed to Musculoskeletal Risk Control
and Disorders in Manufacturing Industries: A Systematic
Review
submetido à revista: Applied Ergonomics
35
Job Rotation Designed to Musculoskeletal Risk Control and Disorders in
Manufacturing Industries: A Systematic Review.
Rosimeire Simprini Padula, PhD1*
, Maria Luiza Caires Comper, MS1, Emily H. Sparer PhD
2,
Jack T Dennerlein, PhD3,4
1. Masters and Doctoral Programs in Physical Therapy, Universidade Cidade de São
Paulo, São Paulo, Brazil.
2. Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public
Health, Boston, Massachusetts, United States.
3. Department of Environmental Health, Harvard T.H. Chan School of Public Health,
Boston, Massachusetts, United States.
4. Department of Physical Therapy, Movement, and Rehabilitation Sciences Bouvé
College of Health Sciences, Northeastern University, Boston, Massachusetts, United States.
*Autor Correspondente
Rosimeire Simprini Padula
E-mail: [email protected]
Masters and Doctoral Programs in Physical Therapy, Universidade Cidade de São Paulo, Rua
Cesario Galeno 475, 03071-000 - São Paulo-SP, Brazil.
Tel.: +55 11 21781564
36
ABSTRACT
To better understand job rotation in manufacturing industry we conduct a systematic review
asking the question do job rotation programs reduce overload and prevent musculoskeletal
disorders. We searched MEDLINE, EMBASE, Business Source Premier, ISI Web of
Knowledge, CINAHL, PsyINFO, Scopus and SciELO databases for articles published in
peer-reviewed journals. From 10.809 potential articles 71 were read for full text analysis. Of
the fifteen studies included for data extraction, three were intervention studies, one was a
case-control study, and eleven were cross-sectional studies. Only one study was scored with
good methodological quality. The studies reported mixed results, which appear to be
influenced by production models, organization and implementation of job rotation. Currently
little to no evidence exists supporting job rotation as a strategy for control and prevention of
musculoskeletal disorders. Better quality studies are needed to truly document the
effectiveness of job rotation.
Keywords: Task rotation, Ergonomics, Industrial workers
PROSPERO Registration Number: CRD42014013319
37
1. Introduction
Job rotation programs emerged in the 1980s and 1990s as an organizational strategy
with the goal of increasing the performance and the flexibility of workers (Cristini and
Pozzoli, 2010; Kernan and Sheahan, 2012). These programs have often been adopted by
engineers and managers to reduce the time and production costs (Azizi and Liang, 2013;
Corominas et al., 2006; Moreira and Costa, 2013). Initial motivations for implementing job
rotation programs was part of a lean production system and total quality, focused on the need
for more workers with more autonomy (Corominas et al., 2006; Cristini and Pozzoli, 2010).
Currently, job rotation programs are frequently recommended to mitigate continuous
exposure to risk factors for musculoskeletal disorders (Leider et al., 2015a; Mathiassen,
2006).
The definitions for the job rotation are many and vary according to the purpose for
which this strategy is adopted. In terms of management, it can be defined as an alternation
between workers tasks and jobs that require different skill and responsibility (Huang, 1999).
In terms of musculoskeletal risk control, job rotation is defined as a strategy to alternate the
workers between tasks with different exposure level and occupational demands (Howarth et
al., 2009; Jorgensen et al., 2005), which aims at avoiding overloading local body parts
(Mathiassen, 2006).
The planning and implementation of job rotation programs are most specific to each
professional sector and essential to the success of the intervention (Frazer et al., 2003). The
success depends on several criteria and parameters to generate the most effective job rotation
risk control and prevention of musculoskeletal diseases (Leider et al., 2015b). The main
criteria are to identify physical, cognitive and organizational demands; determine exposure
levels; and, evaluate and define how the job rotation schedule will be created. After that, all
workers should be trained to each job to develop the competence and skills and to ensure the
process and products quality (Guimarães et al., 2012). It is also necessary to consider others
factors, such as psychosocial (job satisfaction, engagement) and environmental, can affect
worker health outcomes and the success of the health promotion and prevention programs (Ho
et al., 2009; Park and Jang, 2010).
There are numerous reasons justified by the manufacturing industry and described in
the literature for the selection of job rotation as an ergonomic organizational strategy
(Corominas et al., 2006; Jorgensen et al., 2005). Therefore, studies that have evaluated the
38
effects of job rotation do not always use the same criteria to evaluate the positive or negative
aspects of this intervention, leading to challenges in practical application for practitioners and
researchers.
This review aims to identify evidence for the efecctiveness of job rotation on
improving musculoskeletal health, and investigates whether or not this evidence varies across
different implementation schemes. The definition of job rotation used in this study is the
rotation of workers to tasks with different exposure levels and job demands for workers who
have a daily load of 8 hours (480 minutes), with a lunchbreak.
The specific questions addressed in this review are:
1. What is the effect of job rotation in terms of
a) specific work-related musculoskeletal issues (disorders, complaints, pain and
discomfort),
b) exposure to know risk factors, specifically physical risk factors (posture, force,
biomechanics, fatigue, effort exertion) and
c) psychosocial (job satisfaction, stress, job control, engagement) in manufacturing
industry workers?
2) In addition, with this specific knowledge of the effects of job rotation, how should such
rotation be designed?
2. Methods
2.1. Search strategy
Independent searches were conducted in electronic databases: MEDLINE, CINAHL,
EMBASE, Business Source Premier, ISI Web of Knowledge, PsyINFO, Scopus and SciELO,
in English language, without restricting the publication date. The search terms were defined
based on the list of terms used in the systematic review studies of the Institute for Work &
Health and National Institute for Occupational Safety and Health (NIOSH). The search terms
were grouped into three categories according the principles of "PICO”. The following is an
example of the group terms: Population (Workers OR Employees); Intervention (Job rotation
OR Task rotation); Outcomes (Musculoskeletal disease OR Work ability). Groups of terms
used for search strategies can be seen in Appendix I. The last search was completed on
October 17, 2014.
39
2.2. Inclusion and Exclusion Criteria
The eligible studies included contained all of the following criteria: (1) population of
manufacturing workers; (2) exposures to known risk factors (biomechanical overload,
repetitive tasks, fatigue, posture at work, force, etc.) musculoskeletal disorders (pain,
discomfort, absenteeism), and psychosocial factors; (3) written in English; (4) full text papers
published in peer-reviewed journals; and (5) designed experimental and observational studies:
cohort, case-control, clinical trials and cross-sectional. Excluded studies included the
following: outcomes of productivity and costs only, outcomes that were assessed through
qualitative methods only, studies in which the definition of job ration was different than our
aforementioned definition and those that evaluated variability of factors within a single given
task without changing tasks. The search results were exported to EndNote ® X7 software
where duplicates were removed and extraction of data was obtained in full text.
2.3. Study Analysis
The review process consisted of first deciding which studies to include through review
of 1) the titles and, (2) reading the abstracts. If necessary then full text was reviewed. Two
independent researchers (RP and ML) completed the inclusion review. In cases of
disagreement between the two reviewers the decision was reached by consensus, or a third
researcher (ES) was consulted and the decision was made by arbitration.
Methodological Quality Assessment of Studies
Identified studies were then assessed for their quality according to criteria of internal
and external validity (Sanderson et al., 2007). We used the quality assessment tools proposed
by U.S. National Institutes of Health (NIH). These included for the Quality Assessment of
Controlled Intervention Studies (Appendix 2), Quality Assessment Tool for Observational
Cohort and Cross-Sectional Studies (Appendix 3) and Quality Assessment Tool of Case-
Control Studies (Appendix 4), which had 14 items and 12 items, respectively. Items in these
tools included: reporting; sample size; inclusion criteria; measures of exposure; assessment
bias; and, statistical analysis.
The quality rating was classified as good, fair or poor according to general analysis of
the evaluators considering all items described above. The study quality was determined by the
total number of positive (+) items and the rating classification adopted by Wong et al. (2008).
40
The studies with 67% or more positive items checks were an indication of good quality,
studies with 34-66% positive checks were an indication of fair quality, and 33% or less were
an indication of poor quality (Wong et al., 2008).
2.5. Data Extraction
Data extracted included the following: (1) year of publication; (2) the manufacturing
industry sector; (3) country where the study was conducted; (4) study design type; (5)
characteristics of participants; (6) task (e.g. repetitive with short cycles, handling load); (7)
methods for the organization of a job rotation (e.g. simple or using an equation); (8)
parameters used to define job rotation (e.g. biomechanics, organizational, cognitive, motor
learning curves, production aspects); and, (9) job rotation schedules (e.g. protocol, time, and
priorities). Two independent reviewers extracted the data and, in case of disagreement;
consensus was reached by discussion between the reviewers or by arbitration by a third
reviewer.
In the original proposal and PROSPERO register, it was indicated that meta-analysis
would be carried out. However, due to the large heterogeneity of study designs, criteria and
measuring instruments used in the studies, the analysis was not possible. Thus, results from
this study are presented descriptively.
3. Results
3.1. Characteristics of the studies and methodological quality
The search resulted in 10.809 potentially eligible studies, of which 1.362 were
duplicates, and 9.376 were excluded based on the review of the titles and abstracts. An
addition 56 studies were excluded after review of the full-text, leaving fifteen studies (Figure
1) for data extraction.
41
Figure 1- Flowchart of Systematic Review Process
The final fifteen studies were from five countries and the majority of which (eight
studies) examined assembly line area of Automotive/Automobile industry (Asensio-Cuesta et
al., 2012b; Asensio-Cuesta et al., 2012a; Dawal et al., 2009; Dawal and Taha, 2007; Diego-
Mas et al., 2009; Frazer et al., 2003; K. Fredriksson et al., 2001; Roquelaure et al., 1997).
Most of studies (nine) proposed job rotation schedules exclusively between tasks with short
cycle time and highly repetitive movements (Asensio-Cuesta et al., 2012b; Asensio-Cuesta et
al., 2012a; Balogh et al., 2006; Diego-Mas et al., 2009; Filus and Okimorto, 2012; Frazer et
al., 2003; Fredriksson et al., 2001; Roquelaure et al., 1997; Sato and Coury, 2009) (Table1).
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097
Formoreinformation,visitwww.prisma-statement.org.
MEDLINE: 2483 CINAHL: 1538
EMBASE: 1078
Business Source Premier: 2754 Scopus: 2003
ScIELO: 420
ISI Web of Knowledge: 331 PsycINFO: 201
Screening
Included
Eligibility
Iden
tification
Relevant studies
(n = 10808)
Records screened
(n = 9446)
Records excluded
(n = 9376)
Full-text articles assessed for eligibility
(n = 71)
Excluded for final decision:
Other language (n=1)
Not full paper (n=7) Overload analyses (n=13)
Analysis of the tasks multiple (n=7)
Opinion text (n=7)
Guidance (n=2) Productivity equations (6)
Others populations (n=11)
Survey with manager and coordinators (n=2)
Results companies
together (1)
Studies included in qualitative synthesis
(n = 15)
Duplicates excluded
(n = 1362)
42
Table 1 - Characteristics of the studies included in Systematic Review
Of the 15 studies included, two were rated as good (Roquelaure et al., 1997), six as
fair (Balogh et al., 2006; Dawal et al., 2009; Dawal and Taha, 2007; Guimarães et al., 2012;
K. Fredriksson et al., 2001; Sato and Coury, 2009), and seven as poor methodological quality
(Asensio-Cuesta et al., 2012b; Asensio-Cuesta et al., 2012a; Carnahan et al., 2000; Diego-
Mas et al., 2009; Filus and Okimorto, 2012; Frazer et al., 2003; Tharmmaphornphilas and
Norman, 2007a).
The study designs consisted of three clinical trials (Comper and Padula, 2014;
Guimarães et al., 2012; K. Fredriksson et al., 2001), one case-control study (Roquelaure et al.,
1997) and eleven cross-sectional studies (Asensio-Cuesta et al., 2012b; Asensio-Cuesta et al.,
2012a; Balogh et al., 2006; Carnahan et al., 2000; Dawal et al., 2009; Dawal and Taha, 2007;
Diego-Mas et al., 2009; Filus and Okimorto, 2012; Frazer et al., 2003; Sato and Coury, 2009;
Tharmmaphornphilas and Norman, 2007a). Comper and Padula (2014) had not evaluated
methodological quality because it was a protocol study. The other two clinical studies were
non-randomized controlled trials and were rated as fair (Guimarães et al., 2012; K.
Fredriksson et al., 2001)(Table 2).
RCT CS C CC
Textile/Manufacturing cells Brazil x
Home appliances/Assembly line Brazil x
Automobile parts/Assembly line NR x
Automobile parts/Assembly line NR x
Footwear Brazil x
Automobile parts/Assembly line NR x
Office products Brazil x
Automotive Malaysia x
Automotive Malaysia x
Manufacturing cells NR x
Wooden boards for parquet
flooring/ Assembly linesSweden x
Automotive/Assembly line Canada x
Automobile/Assembly line Sweden x
Manufacturing cells NR x
Television, Shoes and Automobile
brakes France XHigh repetitive movements (under 30 seconds)
Manufacturing Industry Job characteristics
Not reported
Not reported
Lifting tasks.
Higher repetitive (67 seconds)
Repetitive movements (60 seconds)
Repetitive movements (cycle time between 15 and
90 seconds)
Repetitive (cycle shorter than 90 seconds)
High repetitive movements
High repetitive movements
Task with different complexities
High repetitive movements
Repetitive movements and Materials handling
CountryStudy Design
Task with different complexities
Lifting tasks
RCTs – Randomized Control Trial; CS – Cross Sectional; C - Cohort; CC – Case Control; NR not reported; NA – not applicable. Were used
the first´s author name on the tables.
43
Table 2- Methodological quality of studies
+ (Yes), - (No), NR - not reported, NA – not applicable, CD – cannot determine, T- Total punctuation; QR - Quality
Rating (67 % or more - Good, 33- 66% - Fair, 33% or less - Poor), Quality Tool - † Appendix 2 (Criteria:Randomization
(1 and 2): Allocation (3, 6 and 13); Blinding (4 and 5); Outcomes (9, 10 and 11); Dropout rate ( 7,8 and 12);
Confounding (14); ††Appendix 3 (Criteria: Setting (1 and 2); Allocation (3, 4 and 5); Outcomes (6,7,8,9,10,11 and 12);
Dropout rate (13); Confounding (14); †††Appendix 4 (Criteria: Setting (1 and 2); Allocation (3, 4, 5 and 6);
Randomization (7 and 8); Outcomes (9 and 10); Blinding (11); Confounding (12).
3.2 Job rotation outco mes measure
In terms of outcomes, eight studies examined clinical outcomes (disability, disorders,
pain, discomfort) (Balogh et al., 2006; Carnahan et al., 2000; Comper and Padula, 2014;
Guimarães et al., 2012; K. Fredriksson et al., 2001; Roquelaure et al., 1997; Sato and Coury,
2009; Tharmmaphornphilas and Norman, 2007a), seven studies examined changes in
exposure to physical risk factors (biomechanics, repetition, fatigue, effort exertion) (Asensio-
Cuesta et al., 2012b; Asensio-Cuesta et al., 2012a; Balogh et al., 2006; Diego-Mas et al.,
2009; Filus and Okimorto, 2012; Frazer et al., 2003), and three examined psychosocial factors
(job satisfaction) (Comper and Padula, 2014; Dawal et al., 2009; Dawal and Taha, 2007;
Guimarães et al., 2012) (Table 3).
Table 3 – Description the studies included in systematic review
Table 3 (cont.) – Description the studies included in systematic review
Table 3 (cont.) – Description the studies included in systematic review
Table 3 (cont.) – Description the studies included in systematic review
Table 3 (cont.) – Description the studies included in systematic review
The participants of the studies were of the both genders, in working-age (18-65 years),
with samples ranging from 11 to 957 workers, and with 4 to 25 workstations.
The indicators and tools used to evaluate the outcomes varied widely. The majority of
the studies used tools that had either dichotomous (yes or no) or Likert (0-10) scales
responses. The Likert scale was evaluated immediately after job rotation occurred or in a
follow up period of between one and three and a half years. While six studies proposed job
rotation schedules using equations or mathematic algorithm, which proved be able of to
generate the best job rotation solution (Asensio-Cuesta et al., 2012b; Asensio-Cuesta et al.,
2012a; Carnahan et al., 2000; Comper and Padula, 2014; Diego-Mas et al., 2009; Frazer et al.,
2003; Tharmmaphornphilas and Norman, 2007a) (Table 3).
Overall it appears that the evidence about job rotation is mixed. One study with good
quality had a positive results job rotation (Roquelaure et al., 1997). Of the six studies with fair
quality, three of these were positive (Dawal et al., 2009; Dawal and Taha, 2007; Guimarães et
al., 2012), two negative evidence (K. Fredriksson et al., 2001; Sato and Coury, 2009) and one
study the results were inconclusive evidence (Balogh et al., 2006). There were eight studies
with poor evidence and the results varied widely. For example, two studies found that job
rotation did not influence absence from work by sick leave amount (Sato and Coury, 2009)
and resulted in increase in reported musculoskeletal diseases (K. Fredriksson et al., 2001).
However, Guimarães et al. (2012) found positive findings in the reduction of the absence
from work, musculoskeletal disease and production losses in job rotation group. Even as
Roquelaure et al. (1997) found an association between low occurrences of carpal tunnel
syndrome in workplace where job rotation was implemented. Whereas other studies indicated
a positive increase in job satisfaction (Dawal et al., 2009; Dawal and Taha, 2007; Guimarães
et al., 2012). Others studies did not direct its conclusions about job rotation effects (Asensio-
Cuesta et al., 2012b; Asensio-Cuesta et al., 2012a; Carnahan et al., 2000; Diego-Mas et al.,
2009; Filus and Okimorto, 2012; Frazer et al., 2003; Tharmmaphornphilas and Norman,
2007a).
3.3 Parameters for the organization and implementation of job rotation schedules
The parameter used to create job rotation schedules varied. These parameters included
biomechanical exposure to physical risk factors (thirteen studies) (Asensio-Cuesta et al.,
2012b; Asensio-Cuesta et al., 2012a; Balogh et al., 2006; Carnahan et al., 2000; Comper and
Padula, 2014; Diego-Mas et al., 2009; Filus and Okimorto, 2012; Frazer et al., 2003;
Guimarães et al., 2012; K. Fredriksson et al., 2001; Roquelaure et al., 1997; Sato and Coury,
2009; Tharmmaphornphilas and Norman, 2007a), organizational (twelve studies) (Asensio-
Cuesta et al., 2012b; Asensio-Cuesta et al., 2012a; Carnahan et al., 2000; Comper and Padula,
2014; Dawal et al., 2009; Dawal and Taha, 2007; Diego-Mas et al., 2009; Filus and Okimorto,
2012; Frazer et al., 2003; Guimarães et al., 2012; K. Fredriksson et al., 2001; Roquelaure et
al., 1997), cognitive (seven studies) (Asensio-Cuesta et al., 2012b; Comper and Padula, 2014;
Dawal et al., 2009; Dawal and Taha, 2007; Diego-Mas et al., 2009; Guimarães et al., 2012;
Sato and Coury, 2009). Psychosocial factors were described in five studies (Asensio-Cuesta et
al., 2012b; Dawal et al., 2009; Dawal and Taha, 2007; Guimarães et al., 2012; K. Fredriksson
et al., 2001). Environmental factors and safety aspects were also mentioned in five studies
((Asensio-Cuesta et al., 2012b; Asensio-Cuesta et al., 2012a; Diego-Mas et al., 2009;
Guimarães et al., 2012; Roquelaure et al., 1997). Only tree studies (Asensio-Cuesta et al.,
2012b; Diego-Mas et al., 2009; Guimarães et al., 2012) used all the parameters mentioned
previously. In most of the articles, after the parameter description, the author indicated that
rotation occurred between different biomechanical risk level (Asensio-Cuesta et al., 2012b;
Asensio-Cuesta et al., 2012a; Balogh et al., 2006; Comper and Padula, 2014; Diego-Mas et
al., 2009; Filus and Okimorto, 2012; Frazer et al., 2003; Guimarães et al., 2012; Roquelaure et
al., 1997; Sato and Coury, 2009; Tharmmaphornphilas and Norman, 2007a) or complexity
levels of task or both (Diego-Mas et al., 2009; Filus and Okimorto, 2012; Guimarães et al.,
2012).
Most of the studies describing job rotation schedules were organized in four rotations
per day, being three after two hours long and one after an hour of work (Asensio-Cuesta et al.,
2012b; Comper and Padula, 2014; Diego-Mas et al., 2009; Guimarães et al., 2012). There are
studies that proposed definition of job rotation or evaluated the best time between each
schedule, considering aspects such as fatigue (Filus and Okimorto, 2012), characteristics of
production and tasks (Asensio-Cuesta et al., 2012a; Carnahan et al., 2000;
Tharmmaphornphilas and Norman, 2007a) or did not report the time between each job
rotation (Dawal et al., 2009; Dawal and Taha, 2007; Roquelaure et al., 1997).
Table 4- Strategies to implement job rotation schedules
Biomechanical Organizational Cognitive/Mental Others
Comper (2014) Posture at work: sitting,
kneeling, standing, walking
Movements analysis:
amplitude and frequency
Exposure risk level: low,
moderate and high
Use of tools and machines
Percentage of occupation in
work cycles
Mental Capacities:
autonomy
Not reported Each 2 hours Ergonomic analysis
Quick Exposure Check
(QEC)
Rapid Entire Body
Assessment (REBA)
Rotation between
different biomechanical
risk level - low,
moderate and high risk
Not reported (1) The level of exposure
intensity
(2) Predominantly posture at
work
(3) The main physical demand
(material handling, repetition of
movements, static posture)
(4) Body regions of higher
overhead
(5) Production’s specificities
Filus (2012) Muscular overload: apply
for different muscular group
activity
Perception about
complexity of tasks: easy,
moderate or dificult
Not Reported Not reported One, two and three hours
(1ª week - Each one
hour; 2ª week -Each 2
hours; 3ª week - Each 3
hours)
Not Reported Rotation between
different complexity
levels of task - easy,
moderate and difficult
Not reported (1) Biomechanics analysis
(2) Staff engaged
Asensio-Cuesta
(2012a)
Posture: awkward
Movements of analysis:
amplitude and frequency,
stereotypy,
lack of postural variation,
inadequate recovery
periods
Force : application of force
Turn duration; Breaks Not Reported Safety aspects:
Protection use of gloves
Enviromental factors:
exposure to cold
Four job rotations per
day. 1st, 2nd and 3 th (2
hours) and 4th (1 hour).
Computational Software
Genetic Algorithm (GA)
and OCRA method
Rotation between
different biomechanical
risk level - low,
moderate and high risk
Not reported (1) Know the performance the
tasks by the worker
(2) Biomechanical risk level
(3) Ergonomic staffs: analysis
continues to observe sensitive
changes
Asensio-Cuesta
(2012b)
Posture at work: standing,
climbing,
Movements of analysis:
frequency, limitations to
perfomance, coordinating
movements
Force: exerting force
standing still and movement
Competence Criteria
writing, using computer
(mouse and keyboard),
driving vehicles, hearing,
know the company
strategies and policies and
adaptability and self-control,
learning skills, engagement
and responsibility,
willingness)
Cognitive Demand:
hearing, locating direction
of sound, seeing from a
distance
Psychosocial factors:
enthusiasm, meticulous
and rigorous work
Safety aspects: working
at heights
Four job rotations per
day. 1st, 2nd and 3 th (2
hours) and 4th (1 hour).
ECRot model -
Computational Software
Genetic Algorithm (GA).
(39 criteria were used to
characterize the workers
and jobs included in the
rotation schedules)
Rotation between
different biomechanical
risk level - low,
moderate and high risk
Not reported (1) Know the performance the
tasks by the worker
(2) Minimization of fatigue
accumulation
(3) Competence and Physical
skills demanded by the tasks
Guimarães (2012) Biomecachical risk
factors
Workstation:
characteristics, layout, task
content, task design
Issues related to the
organizational culture.
Complexity of the task:
easy, moderate or dificult
Mental Capacities and
Cognitive Demand: rate
of learning; learning
Curve (LC) to each task
Psychosocial factors:
participative approach
(company and workers),
preferences of workers
Safety: risk of task
Enviromental factor:
general physical aspects.
Each 2 hours (beginning)
to Time decided by
workers (each 1.5 hours)
after implementation.
Learning Curve (LC) modeling ; Macroergonomic Work Analysis (MA)Rotation between
different complexity
levels of task - easy,
moderate and difficult
Training (1) Training for all workers (3.5
years) (2) After initial criteria’s
the workers themselves
established the job rotation.
Priorities to organize job
rotationImplementationAuthors/Year
Parameters/Demands Protocol and Intervals
(Time )Tools to risk analysis Schedule
Table 4 (Cont.) – Strategies to organize and implement job rotation schedules
Biomechanical Organizational Cognitive/Mental Others
Diego-Mas (2009) Posture at work: standing,
sitting, walking, climbing,
Movements analysis:
amplitude and frequency
Physical capacities:
coordination movements
Force: applying force in
movement (transport, push,
pull)
General capacities:
driving vehicles, working at
height, writing, speaking,
using keyboard and mouse
Mental Capacities:
complex decisions,
responsibility,
cooperation with others,
attention/concentration/a
utonomy
Cognitive demands:
long distance vision,
color vision, hearing
locating the direction,
tactile sensivity,
smelling/tasting,
Safety aspects:
personal protection
equipment,
Enviromental factor:
confined places
Four job rotations per
day. 1st, 2nd and 3th (2
hours) and 4th (1 hour).
Organization Job rotation
schedule according risk
factors.
Computational Software
Genetic Algorithm (GA)
DPI-ASEPEYO genetic
algorithm;
MORE software – to
obtain the maximum
flexibility.
Rotation between
different movements
demands and work
content
Not reported (1) Biomechanics criteria
(2) Mental capacities
(3) Communication capacities
Sato (2009) Posture at work: standing,
sitting or walking
Not reported Mental Capacitites:
Intensity of the work
(heavy or light).
Cognitive demands:
high for sorting products
or low for exclusively
manual activities.
Not reported Job rotation schedule to
modify
the exposure patterns.
Each one hour.
Ergonomic Workplace
Analysis (EWA)
Rotation between
different cognitive and
physical demands -
high physical/low
cognitive demands and
high cognitive /low
physical demands
Not reported (1) Biomechanical demands
(2) Mental and Cognitive
demands
Dawal (2009) Not reported Job organization: job
rotation, work method,
training, problems solving
and goal setting
Mental Capacities:
power decisions, self-
regulation and worker
autonomy.
Psychosocial factors:
job satisfaction
Not reported Not reported Not reported
(Dawal,2007) Not reported Job organization: job
rotation, work method,
training, problems solving
and goal setting
Mental Capacities: job-
related decisions, self-
regulation and worker
autonomy
Psychosocial factors:
job satisfaction
Not reported Not reported
Tharmmaphornphilas
(2007)
Task caracteristics: Lifting
weight (kg). Lifting
frequency (cm). Lifting
height (cm). Horizontal
lifting distance (cm). Lifting
rate (lifts/minute)
Not reported Not Reported Not Reported Different schedule of
work to different
scenarios
Each one hour ( workers
perform tasks during the
first 50 minutes and relax
during the last 10
minutes)
Mathematical models
deterministic and
stochastic problems for
Minimizing the maximum
number of lost days
(StochMinMaxDays) and
Minimizing the total
number of lost days
(StochMinTot-Days).
Rotation considering the
subtask demand
Not reported (1) Lifting weight (kg)
(2) Lifting rate (lifts/minute)
(3) Lifting distance (cm)
Balogh (2006) Posture at work
Moviment analysis:
amplitude and frenquency
Muscular overload :
muscle activity
Not reported Not Reported Not Reported All operators - Five work
tasks per day.
Not reported Not reported Not reported Not reported
ImplementationPriorities to organize job
rotationAuthors/Year
Parameters/Demands Protocol and Intervals
(Time )Tools to risk analysis Schedule
Table 4 (Cont.) – Strategies to organize and implement job rotation schedules
Biomechanical Organizational Cognitive/Mental Others
Frazer (2003) Physical demands:
workload posture and
moviments
Anthropometric criterial:
height and weight.
Force: magnitude hand grip
force.
Task caracteristics: lifting
limit
Cycle time Not Reported Sociodemographic
caracteristics: gender
Two jobs Computational software -
Biomechanical model:
estimate the moment of
force and reaction forces
for the major body joints
(low back).
Not reported Not reported (1) Peak L4/L5 shear force and
moment cumulated.
Fredriksson (2001)
Moviment analysis:
amplitude and frequency
Physical demands:
workload regarding
strenuous postures and
movements
Job demands: Workpace,
workload
Competence Criterial:
demand for skill and
creativity
Opportunities to influence
work: Monotony
Not Reported Psychosocial factors:
support at work,
occupational pride
stimulation from work
oportunities to influence
work
Four times per day. Not reported Rotation successively
implementation of job
rotation - production team
decision
Training (1) Training operators (Six-month
training)
(2) Recruited person
Carnahan (2000) Physical demands: lifting
capacities, spent to
performing others tasks. .
Organizational demands
and
time spent performing other
tasks.
Complexity of the taks:
easy or difficult)
Not Reported Sociodemographic
caracteristics: gender
One or two hours –
dependents of the
characteristics of task
(easy or difficult).
Computational Software
Genetic Algorithm (GA)
Rotation according to
gender capacity groups
Not reported (1) Lifting weight (kg), Lifting rate
(lifts/minute), Lifting distance
(cm)
(2) Gender and lifting capacity
Roquelaure (1997) Moviment analysis:
frenquency
Task caracteristics:
pinching, gripping,
screwing, pulling, pushing,
lifting, turning, Force:
Production caracteristics
Use of tools
Work pace
Capactities to decision
Not Reported Enviromental factor:
cold and vibration
Not reported Checklist based on the
RULA method
Not reported Not reported (1) Two or more workstations to
considerer job rotation;
(2) Biomechanical risk factors
Authors/YearParameters/Demands Protocol and Intervals
(Time )Tools to risk analysis Schedule Implementation
Priorities to organize job
rotation
37
There were six studies that used mathematic equations and software to organize the
job rotation schedules, four studies organized the job rotation from the parameters previously
defined often with the support of the production teams, health, and safety (Asensio-Cuesta et
al., 2012b; Asensio-Cuesta et al., 2012a; Carnahan et al., 2000; Diego-Mas et al., 2009; Fraser
and Hvolby, 2010; Tharmmaphornphilas and Norman, 2007a). Job rotations were
implemented with the training of workers in two studies and there were not reported job
rotation implementation in other studies. The criteria and parameters used to organize and
implement job rotation schedule are reported in Table 4.
4. Discussion
The objectives of this systematic review were to identify the effect of job rotation on
1) specific work-related musculoskeletal issues; 2) exposure to known risk factors,
specifically physical risk factors; and, 3) psychosocial risk factors. Additionally, this review
aimed to determine how job rotation should be designed. The results were inconclusive with
regard to the effectiveness of job rotation. Although there was a great variability of
parameters described, in most of the studies, biomechanical and organizational factors were
used to define the job rotation schedules. There was however some similarity in the
scheduling, as job rotation shifts tended to vary between one or two hours in each study.
The mixed results about job rotation effectiveness can be explained by the variability
in different outcomes measures and results of the non-randomized clinical trials, proposed by
Guimarães et al. (2012) and Fredriksson et al. (2001). Guimarães et. al (2012) reported
positive results associated with job rotation, while Fredriksson et al. (2001) determined that
job rotation did not contributed to MSD reduction. Probably, this is due to different
understanding of the meaning of the job rotation as strategy for the prevention and control of
MSDs.
Fredriksson et al. (2001) used job rotation as a way to fragment tasks and increase
the production rate, as if breaking up tasks could reduce this burden for workers. They
evaluated workers of the car-body-sealing department at an automobile assembly plant and
compared those who worked on car in line out system (control group) with workers job
rotation schedules in line system whose each workers did part of the job (Intervention group).
The line system with job rotation had worse outcomes than line out system, as the physical
workload and MSDs increased significantly (p<0.05). Furthermore, workers reported lower
job control and consequently, were less stimulated. Guimarães et al. (2012) prioritized the
38
acquisition of skills by workers to job rotation schedules and evaluated job rotation effects
after 3.5 years indicated a significant reduction in work-related musculoskeletal injuries,
absenteeism, turnover, rework, and spoilage between those with the job-rotation scheduling
and those without it.
In addition, Roquelaure et al. (1997) found a positive association between the carpal
tunnel syndrome and workers who perform job rotation. However, the design of this study
(case-control) it has the potential for risk of bias, especially because the data was collected
retrospectively, making difficult to assess exposure. Similarly, Balogh et al. (2006) and Sato
and Coury (2009) proposed another study design (cross-sectional) that allow not confirm the
effectiveness of job rotation. Furthermore, these studies are not described job rotation with
main intervention strategy that generates various confounding the measured outcomes.
There were three studies reported positive results job rotation implementation with
increasing job satisfaction (Dawal and Taha, 2007; Guimarães et al., 2012). Even though,
these results are not directly related to the prevention or control of musculoskeletal disorders,
surely they influence the acceptance of job rotation, which is also associated with health
outcomes (Rissen et al., 2002). Dawal et al. (2009) and Dawal and Taha (2007) studies
evaluated of effect various organizational factors (work methods, training, job rotation)
showing positive job rotation correlation with job satisfaction independent age and the
approval of 70% of workers. Guimarães et al. (2012) observed that after training works to job
rotation implement the workers were more confidence to develop a task and showed more
satisfaction with work. These findings shown the greater involvement and worker training to
accomplish the task were positive and improve job satisfaction, although the studies
methodological quality were fair with cross-sectional design.
We found a great number of parameters for organization and implementation job
rotation. Biomechanical and organizational parameters were the most used and, especially,
include aspects related to posture, movement frequency, level of exposure and complexity
level of task. These findings were consistent with the ergonomic job rotation purposes of
alternating tasks of the different complexities and biomechanical requests (Guimarães et al.,
2012; Mathiassen, 2006). On the other hand, interestingly, we found a large number of studies
that proposed the job rotation of tasks with high repeatability and no possibility of variation of
production rate and movements (Asensio-Cuesta et al., 2012b; Asensio-Cuesta et al., 2012a;
Balogh et al., 2006; Diego-Mas et al., 2009; Filus and Okimorto, 2012; Fraser and Hvolby,
2010; K. Fredriksson et al., 2001; Roquelaure et al., 1997). In these cases, the job rotation
may well not reduce overload and increase worker stress. The implementation of job rotation
39
in tasks with high repeatability seems to meet the problem caused by the fragmented work on
production lines. This result could be related to the fact that many companies implemented
job rotation programs with production, cost, and quality in mind, not employee health (Azizi
and Liang, 2013; Costa and Miralles, 2009; Michalos et al., 2010; Moreira and Costa, 2013).
Another related explanation could be that companies implemented job rotation program with
the goal of expanding the skills or from a production rearrangement (Balogh et al., 2006;
Guimarães et al., 2012; K. Fredriksson et al., 2001; Roquelaure et al., 1997; Sato and Coury,
2009).
Regarding the job rotation schedules, the most studies indicated mathematical
equations or algorithms to create proposals for switching between tasks, for situations where
the working day is 8 hours, with intervals of one or two hours (Asensio-Cuesta et al., 2012b;
Carnahan et al., 2000; Comper and Padula, 2014; Diego-Mas et al., 2009; Guimarães et al.,
2012; K. Fredriksson et al., 2001; Sato and Coury, 2009). The reasons for the choice for these
intervals were not mentioned in almost all studies. Only Guimarães et al. (2012) described
that a job rotation schedule of every two hours rather than an average one and a half hour was
better for that group. Job rotation was started four time daily each two hours until the workers
acquire skill with for a large number of tasks, then the time average between each job rotation
was 1hour and 30 minutes, and the tasks could be decided by the worker himself (Guimarães
et al., 2012).
In fact, based on this review, we cannot recommend a standard job rotation schedule.
This is because, in general, the studies reported little about the strategies used to perform the
rotation, indicating that job rotation was likely not implemented as a preventive measure for
MSD reduction, rather, for a need for engineering the flexibility of workers. Many of the
equations proposed to define the job rotation schedules relay on a variety of parameters [e.g
posture and movements, mental and cognitive capacities, strategies and policies, learning
skills, responsibility, long distance vision, color vision, hearing locating the direction, writing,
speaking. However, none of the studies describe how they determined that these were the
important factors. Thus, much remains to be studied on these equations to integrate theory and
practice and thereby contribute to decision making in the job rotation implementation.
Job rotation, despite being an important intervention, and founded upon the principles
of ergonomics, was found to be more often used to meet a need for production and for the
training of multifunctional workers. There were many studies identified in this review that
were determined to be of poor or fair methodological quality due to insufficient level of detail
regarding the study population, sample size, power, randomization, blinding, dropout rate,
40
intervention and outcomes. The problem of the poor quality of the studies can possibly be
explained by the difficulty in implementing new health and safety programs in worksites.
Dempsey (2007) described on the benefits of progress and barriers encountered in the design
of research on the effectiveness of ergonomic interventions to prevent MSDs and found that
there was a negative of bias to the evidence of the studies. This study confirms that there is
weak evidence of the effectiveness of job rotation reduce overload and prevent
musculoskeletal disorders in manufacturing industries.
Further studies are required to better methodological quality, although it is necessary
to consider alternative research designs (Schelvis et al., 2015), taking into account among
other factors the specificities of each manufacturing industry and the possibilities within the
differentials production organizations. In addition, identify facilitators or barriers in each
organizational level can contribute to job rotation planning and implementation (Leider et al.,
2015b).
Successful implantation of the job rotation programs depended on a number of
important factors, such as involvement and acceptance of managers, job characteristics,
production method, number of employees and the tasks involved the biomechanics of
exposure level. Thus, it is necessary to analyze the activities that will be part of job rotation,
sort your complexity, perform training (Guimaraes et al., 2012), and determine how long each
worker must remain in each tasks (Tharmmaphornphilas and Norman, 2007b) and meet these
requirements is important for positive results for the workers' health. In addition, we believe
that the scheduling should be selected based on the specifics of the job and individual
characteristics of the workers. Besides, we must not forget that industrial innovation,
adjustments of production and the very ergonomic improvements create different exposure
scenarios and difficult intervention studies (Dempsey, 2007).
5. Limitations
A limitation of this study relates to how the articles included in the review were
selected, as only information in the title and abstract were reviewed initially. The studies did
not follow clear criteria for description of the methods in this way was very difficult to find
the information, which often was in another part of the text. Some studies were excluded
because the results of different manufacturing industries were presented together which
prevented the analysis of information. Others did not present central tendency and dispersion
measurements or statistical analysis.
41
6. Conclusion
We found a few number of current studies on job rotation in manufacturing industries.
While most articles indicated in their goals that they would evaluate job rotation effect; this
was not the majority. Those that did evaluate the effect of the intervention often grouped the
effect with other organizational factors. Although same studies tried to provide support of the
benefits of job rotation, the methodological quality was often poor, and they had inappropriate
designs to assess outcomes. It was therefore not possible to conclude if job rotation was
effective to reduce musculoskeletal overload and disease prevention.
Acknowledgements
The National Counsel of Technological and Scientific Development (CNPq), Brazil
(473651/2013-0 and 249621/2013-4), is funding this study.
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63
Appendix 1
Quality Assessment of Controlled Intervention Studies
Criteria Yes No
Other
(CD, NR,
NA)*
1. Was the study described as randomized, a randomized trial, a
randomized clinical trial, or an RCT?
2. Was the method of randomization adequate (i.e., use of
randomly generated assignment)?
3. Was the treatment allocation concealed (so that assignments
could not be predicted)?
4. Were study participants and providers blinded to treatment group
assignment?
5. Were the people assessing the outcomes blinded to the
participants' group assignments?
6. Were the groups similar at baseline on important characteristics
that could affect outcomes (e.g., demographics, risk factors, co-
morbid conditions)?
7. Was the overall drop-out rate from the study at endpoint 20% or
lower of the number allocated to treatment?
8. Was the differential drop-out rate (between treatment groups) at
endpoint 15 percentage points or lower?
9. Was there high adherence to the intervention protocols for each
treatment group?
10. Were other interventions avoided or similar in the groups (e.g.,
similar background treatments)?
11. Were outcomes assessed using valid and reliable measures,
implemented consistently across all study participants?
12. Did the authors report that the sample size was sufficiently
large to be able to detect a difference in the main outcome between
groups with at least 80% power?
13. Were outcomes reported or subgroups analyzed prespecified
(i.e., identified before analyses were conducted)?
14. Were all randomized participants analyzed in the group to
which they were originally assigned, i.e., did they use an intention-
to-treat analysis?
Quality Rating (Good, Fair, or Poor) (see guidance)
Rater #1 initials:
Rater #2 initials:
Additional Comments (If POOR, please state why):
*CD, cannot determine; NA, not applicable; NR, not reported
Appendix 2
64
Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies
Criteria Yes No
Other
(CD, NR,
NA)*
1. Was the research question or objective in this paper clearly
stated?
2. Was the study population clearly specified and defined?
3. Was the participation rate of eligible persons at least 50%?
4. Were all the subjects selected or recruited from the same or
similar populations (including the same time period)? Were
inclusion and exclusion criteria for being in the study prespecified
and applied uniformly to all participants?
5. Was a sample size justification, power description, or variance
and effect estimates provided?
6. For the analyses in this paper, were the exposure(s) of interest
measured prior to the outcome(s) being measured?
7. Was the timeframe sufficient so that one could reasonably expect
to see an association between exposure and outcome if it existed?
8. For exposures that can vary in amount or level, did the study
examine different levels of the exposure as related to the outcome
(e.g., categories of exposure, or exposure measured as continuous
variable)?
9. Were the exposure measures (independent variables) clearly
defined, valid, reliable, and implemented consistently across all
study participants?
10. Was the exposure(s) assessed more than once over time?
11. Were the outcome measures (dependent variables) clearly
defined, valid, reliable, and implemented consistently across all
study participants?
12. Were the outcome assessors blinded to the exposure status of
participants?
13. Was loss to follow-up after baseline 20% or less?
14. Were key potential confounding variables measured and
adjusted statistically for their impact on the relationship between
exposure(s) and outcome(s)?
Quality Rating (Good, Fair, or Poor) (see guidance)
Rater #1 initials:
Rater #2 initials:
Additional Comments (If POOR, please state why):
*CD, cannot determine; NA, not applicable; NR, not reportedAppendix 3
65
Quality Assessment of Case-Control Studies
Criteria Yes No
Other
(CD, NR,
NA)*
1. Was the research question or objective in this paper clearly stated
and appropriate?
2. Was the study population clearly specified and defined?
3. Did the authors include a sample size justification?
4. Were controls selected or recruited from the same or similar
population that gave rise to the cases (including the same
timeframe)?
5. Were the definitions, inclusion and exclusion criteria, algorithms
or processes used to identify or select cases and controls valid,
reliable, and implemented consistently across all study
participants?
6. Were the cases clearly defined and differentiated from controls?
7. If less than 100 percent of eligible cases and/or controls were
selected for the study, were the cases and/or controls randomly
selected from those eligible?
8. Was there use of concurrent controls?
9. Were the investigators able to confirm that the exposure/risk
occurred prior to the development of the condition or event that
defined a participant as a case?
10. Were the measures of exposure/risk clearly defined, valid,
reliable, and implemented consistently (including the same time
period) across all study participants?
11. Were the assessors of exposure/risk blinded to the case or
control status of participants?
12. Were key potential confounding variables measured and
adjusted statistically in the analyses? If matching was used, did the
investigators account for matching during study analysis?
Quality Rating (Good, Fair, or Poor) (see guidance)
Rater #1 initials:
Rater #2 initials:
Additional Comments (If POOR, please state why):
*CD, cannot determine; NA, not applicable; NR, not reported
Appendix 5
66
MEDLINE
1. (company or companies).mp
2. department$. ti,ab.
3. employee*.mp
4. employer*.mp
5.employer?.ti,ab.
6.employ*.mp.
7. (factory or factories).ti,ab.
8. firm?.ti.ab.
9.industr*.mp.
10. laborer?.ti,ab.
11.labourer?.ti,ab.
12. manager?.ti,ab.
13. operator*.mp.
14. operator?.ti,ab.
15. organization*.mp
16.organi#ations$.ti,ab.
17.occupation*.mp
18. team?.ti,ab.
19. work*.mp
20. work environment.mp
21. worker*.mp.
22. worker?.ti,ab.
23. workplace.mp.
24. workstation.mp.
25. or/1-24
67
26.ergonomics.mp.
27.ergonomic$.ti,ab
28. 26 or 27.
29.job organization.mp.
30.job transfer$.ti,ab.
31.job rotation.mp
32. job design
33. (job adj design).ti,ab
34. (multi adj criteria$).ti,ab
35. multi task/
36. multiskilling/
37. schedule$ adj2 production).ti,ab
38. schedule production.mp
39. personnel rotation
40. (personnel adj rotation).ti,ab.
41. task allocation.mp
42. task rotation.mp
43. task performance.mp
44.(task? adj2 modifi$).ti,ab.
45. organizational learning.mp
46. work schedule.mp
47. work rotation.mp.
48. or/ 29 - 47
49. 28 and 48
50. cost effectiveness analysis.mp
51. management of individual?.ti,ab.
52. organisational polic$.ti,ab.
68
53. return$ to work.ti,ab.
54. stay$ at work .ti,ab.
55. (job adj2 modifi$).ti,ab.
56. (promot$ adj2 recovery).ti,ab.
57. work intervention
58.(work$ adj2 intervention?).ti,ab.
59. absenteeism.mp
60. accidents, occupational.mp
61. claim$.ti,ab
62. cumulative trauma disorder.mp
63. disability management program$.ti,ab.
64. early intervention?.ti,ab.
65. employee satisfaction survey?.ti,ab.
66. employee satisfaction.ti,ab.
67. engagement.ti,ab.
68. functional capacity assessment?.ti,ab.
69. health protection.mp
70. health risk management.ti,ab.
71. healthy workplace strateg$.ti,ab.
72. healthy workplace.mp
73. job accommodation.mp
74. job adaptation/
75. job control.ti,ab.
76. job demand/
77. job performance/
78. job satisfaction/
79. job turnover.ti,ab.
69
80. joint labor management initiative?.ti,ab.
81. long term disability benefit?.ti,ab.
82. long-term disabilit$.ti,ab.
83. lost time.ti,ab.
84. lost workday?.ti,ab.
85. musculoskeletal injuries/
86. musculoskeletal pain/
87. musculoskeletal system/
88. labo?r force participation.ti,ab.
89. musculoskeletal disorders.mp
90. occupational disorders.mp
91. occupational exposure.mp
92. occupational health.mp
93. outcome assessment.mp
94. performance indicators.mp.
95. performance management.ti,ab.
96. periodic medical examination/
97. personnel management.mp
98.or/ 50-97
99. 25 and 49 and 98
CINAHL
S1. compan*
S2. department*
S3. employee
S4. employer
S5.employ*.
70
S6. (factory or factories).
S7.industr*.
S8. manager*
S9. operator*
S10. organization*
S11.occupation*
S12. work*
S13. work environment
S14. workplace.
S15. workstation
S16. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15
S17.ergonomics.mp.
S18.job organization.mp.
S19.job transfer*
S20.job rotation
S21. job design
S22. multi task
S23. multiskilling
S24. schedule production
S25. personnel rotation
S26. (personnel adj rotation).ti,ab.
S27. task allocation.mp
S28. task rotation.mp
S29. task performance.mp
S30.(task? adj2 modifi$).ti,ab.
S31. organizational learning.mp
S32. work schedule.mp
71
S33. work rotation.mp.
S34. 17 or 18 or 19 or 20 or 21 or 22 or 23 or 24 or 25 or 26 or 27 or 28 or 29 or 30 or 31 or
32 or 33
S35. 16 and 34
S36. cost effectiveness analysis.mp
S37. management of individual?.ti,ab.
S38. organisational polic$.ti,ab.
S39. return$ to work.ti,ab.
S40. stay$ at work .ti,ab.
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S42. (promot$ adj2 recovery).ti,ab.
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CAPÍTULO 4
ARTIGO 3
The Effectiveness of Job Rotation to Prevent and Control Work-
Related Musculoskeletal Disorders: A Cluster Randomized
Clinical Trial
Será submetido à revista: The Journal of the American Medical
Association (JAMA)
87
THE EFFECTIVENESS OF JOB ROTATION TO PREVENT AND CONTROL
WORK-RELATED MUSCULOSKELETAL DISORDERS: A CLUSTER
RANDOMIZED CLINICAL TRIAL
Maria Luiza Caires Comper, MS1,2
*, Jack Tigh Dennerlein, PhD3,4
, Rosimeire Simprini
Padula, PhD**
1. Masters and Doctoral Programs in Physical Therapy, Universidade Cidade de São Paulo,
São Paulo, Brazil.
2. Discipline of Physical Therapy, União Metropolitana de Ensino e Cultura, Itabuna, Brazil.
3.Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston,
Massachusetts, United States.
4. Department of Physical Therapy, Movement, and Rehabilitation Sciences Bouvé College
of Health Sciences, Northeastern University, Boston, Massachusetts, United States.
*Corresponding authors
Maria Luiza Caires Comper
E-mail: *[email protected]; **[email protected]
Masters and Doctoral Programs in Physical Therapy, Universidade Cidade de São Paulo, Rua
Cesario Galeno 475, 03071-000 - São Paulo-SP, Brazil.
Tel.: +55 11 21781564
88
ABSTRACT
IMPORTANCE: Several reasons justify the use of job rotation as an organizational strategy
for industrial production lines. It is used for increasing performance, autonomy and flexibility
of workers and alternate continuous exposure to risk factors for musculoskeletal disorders.
However, the effectiveness of job rotation to prevent and control musculoskeletal complaints
has limited evidence.
OBJECTIVE: To investigate the effectiveness of job rotation to prevent musculoskeletal
disorders in industrial manufacturing workers.
DESIGN, SETTING AND PARTICIPANTS: This is a 1-year cluster randomized
controlled trial with blinded assessor. Production departments of a Brazilian textile industry
were randomized into intervention and control groups.
INTERVENTIONS: Both groups received ergonomics training. Intervention group
performed job rotation program.
OUTCOMES AND MEASURES: The primary outcome measure was number of working
hours lost due to sick leave measure (hours) in 3-months follow-up. Secondary outcomes
were measured at baseline and 12-month follow-up and included: musculoskeletal symptoms
(Yes/No), job factors for musculoskeletal pain and disorders (0-10), psychosocial factors and
fatigue(0-100), and general health (0-100) and productivity (0-10).
RESULTS: The final sample included 2 departments into intervention group (N=266) and 2
into control group (N=255). After 12 months, the job rotation program did not significantly
change its effect on number of working hours lost due to the sick leave caused by
musculoskeletal injury. There was also no difference in favor of the intervention group (MD -
5.6 hours, 95% CI -25.0 to 13.8) at 12-month follow-up. There were also no differences
between groups for the secondary outcomes (P > 0.05).
CONCLUSION: The job rotation program was no more effective than the control group in
preventing musculoskeletal disorders in industrial workers.
Trial registration: NCT01979731, November 3, 2013
Keywords: Job design; Physical workload; Industrial Workers
Introduction
Work-related musculoskeletal disorders (WMSDs) are a large problem for workers
and companies because it affects the work ability causing negative effects in quality of life
and productivity and increasing number of days of lost work1. Therefore, achieving effective
interventions for control and management of WMSDs is imperative to reduce the risk of
workers developing this disorders2. The interventions often recommended are: ergonomic
design, participatory ergonomic3, ergonomic guidelines and adjustments, rest breaks at work
and job rotation4.
Job rotation is an organizational strategy widely used in production lines with
manufacturing processes5-8
, with the goal of increasing performance, autonomy and flexibility
of workers9,10
and mitigate continuous exposure to risk factors for musculoskeletal
disorders4,11
. The premise is that the alternation of biomechanical exposure provides rest
period for a muscle group while other groups are being recruited12
. As a result, it reduces
cumulative biomechanical overload in a specific part of body4. Job rotation is recommended
to tasks with repeatability of movements6,13
, load lifting12
or awkward and static postures14,15
.
It is used for reduces monotony and boredom16
, to decrease absenteeism17
, increases worker’s
autonomy, flexibility and satisfaction18
, and reduces stress19
. Moreover, the variability of
tasks included in the job rotation favors workers who have temporary or permanent
disabilities20
.
Job rotation effectiveness depends on several criteria and parameters used to planning
and implementation of this intervention21
. It is recommended to identify the mainly demands;
determine biomechanical exposure levels; create the job rotation schedule; and, train all
workers to each job/task22
. However, there is no consensus about which parameters should be
used for create the Job Rotation23
. Instead of this, the studies that have evaluated the effects of
job rotation described a great variability of parameters, what explains, in part, the conflicting
and inconsistent results11
. There are different purposes for job rotation implementation being
study design and methodological quality other possible explanations for the limited
evidence11,23
. Regarding to the purposes, the job rotation has been used to prioritize the needs
of production, as part of a lean production system and total quality7 or to prevent
musculoskeletal disorders4,11
. Until now, there is no studies whose methodological quality is
and design are adequate to endorse the effectiveness, since most of the studies are cross-
sectional or longitudinal with fair to poor methodological quality23
. As a result, there is a lack
of evidence to support the use of JRP with the purpose to prevent work-related
musculoskeletal diseases.
Therefore, it is concluded that there is a clear and important need for well-designed
studies on the function of rotation has been planned with the purpose to reduce biomechanical
overload. The aim of this study was to evaluate the effect of a JRP with specific criteria to
reduce the biomechanical overload and in the prevention of musculoskeletal disorders in
industrial textile workers.
The hypothesis this study, considering the literature findings, the guidelines,
regulatory standards, and experts in the field is that variability and shorter exposure level to
biomechanical risk caused by job rotation resulting in fewer hours lost due to sick leave for
intervention group. Furthermore, we believe that job rotation would be able to reduce the
occurrence of musculoskeletal symptoms, to improve the perception of workers face the
ergonomic and psychosocial risk factors and increase productivity.
Methods
Design, Setting and Participants
This study was a prospectively registered at ClinicalTrials.Gov (NCT01979731),
cluster randomized controlled trial, with blinded assessment of outcomes. The procedures and
consent form were approved by the Research Ethics Committee of Cidade de São Paulo
University (protocol no. 18170313.5.0000.0064). It was conducted at a large Brazilian textile
industry (N=3000 workers). Four production departments of a large Brazilian textile industry
(Finishing Socks, Finishing Underwear, Sewing Socks and Sewing Underwear) meet the
inclusion criteria and were included in the study. These departments had production layouts
organized into lines or cells, whose rhythm was not determined by machines and allowing
switching between tasks with different biomechanical demands and levels of risk for
musculoskeletal pain and disorders; and never had performed job rotation before.
Sewing departments (453 workers) was composed of cutting and sewing machines. It
was characterized by prolonged sitting, repetitive movements in wrists, hands and fingers, and
static muscular overload on the spine and shoulders. The finishing departments (504 workers)
were composed of industrial machines or tables, or a combination of both. The standing
position was preferably adopted because the majority of the activities required material
handling or small displacements between workstations. Repetitive movements in the upper
limbs were also common, especially in shoulders, wrists and hands. The departments were
grouped by similar demands and level of exposure to risk factors for musculoskeletal pain and
disorders (Finishing Socks + Finishing Underwear and Sewing Socks + Sewing Underwear)
and randomly assigned to intervention and control groups, before baseline measurements24
.
The methods of the study were more detailed in a published protocol24
. However,
some changes beyond the control of researchers occurred during the execution of the study.
One month after having started the study the managers concluded the time spend by workers
in answering the questionnaires was too much and harmed the organization dynamics. So, the
follow-up interval for secondary outcomes could be collected every three months as expected
and previously agreed by the managers, being collected only at baseline and after 12-months
intervention. There was no change to the primary outcome follow-up.
Description of Interventions
Intervention and Control Groups
In both groups studied, workers received ergonomic training taught by a
physiotherapist/ergonomist. The training was conducted on a single day over 4 hours, with
lectures on ergonomic risk factors and their influence on the development of musculoskeletal
symptoms, improvements and adaptations for workstations, work postures and preventive
exercise25
.
Job Rotation Program (Intervention Group)
Procedure to create and implement the Job Rotation Program (JRP)
All departments that received JRP were deployed in three phases. Firstly (June 2013-
September 2013), one of the researchers, with 10-years expertise in ergonomics, arranged a
meeting with the production managers to explain the study proposal and procedures and to
define the sectors that filled the eligibility criteria. After discussing about the characteristics
and peculiarities of the tasks performed in the production departments, the production
managers and researches concluded that only 4 production sectors were sectors with
production lines whose rhythm is not determined by machines and allowing switching
between tasks with different biomechanical demands and levels of risk for musculoskeletal
pain and disorders. Then, managers described the characteristics and particularities of these
sectors, the required level of training and possible difficulties in carrying out the job rotation.
In the second phase (October 2013 - January 2014), an ergonomic analysis of the tasks
performed in the productive sectors was carried out. The purpose of this analysis was to
identify: (1) the main physical demand (materials handling, repetitive movements, static
posture); (2) the predominantly posture adopted to perform the task (sitting, kneeling,
standing, walking); (3) the body regions parts of higher overhead (shoulders, elbows, wrists,
hands, spine); and (4) the intensity of exposure level (low, moderate, high or very high).
The intensity of exposure level were assessed using Quick Exposure Check (QEC)26,27
and Rapid Entire Body Assessment (REBA)28
, which assess the main risk factors for
musculoskeletal disorders (frequency of movement, postures, amount of weight handled,
manual force, visual demands, presence of vibration, work pace, and stress)26,29
and level of
task complexity, classified as either easy or difficult according task characteristics from
cognitive demands and learning time17
. All this information was used for classification of
tasks and definition of job rotation schedule. The workers were trained for two months.
Finally, the job rotation schedule implementation occurred in the third phase
(February 2014 – February 2015). One of the researchers monitored it daily, in the first two
months.
Job Rotation Schedule
Job Rotation Schedule was created according to the following priority criteria: (1)
tasks with low or moderate exposure risk level was alternated with high and very high, (2)
tasks that require a predominantly standing posture was alternate with tasks that require a
sitting posture, (3) handling tasks alternated with tasks requiring repetition of movements, and
(4) tasks alternate body regions of higher overhead. The completion of the rotation took place
at intervals of 2 hours because this interval time is compatible with a lower lactic acid30
and
has been consensus in several other studies23
.
Sample size calculation
The study was designed to detect a between-group difference reduction of 10%
working hours lost due to sick leave by musculoskeletal injuries (M Group International
Classification of Diseases, ICD-10). That means, the groups would have a difference of 100
hours, with a standard deviation of 250 hours. A statistical power of 80%, an alpha of 5%, and
a possible sample loss of up to 15% were also considered. Therefore, a total of 232
participants were required.
Randomization
The randomization was performed by an independent researcher, who was not
involved in recruitment and assessment, using a computer-generated randomization
(www.randomizer.org) with random numbers to define groups. All workers within the
participating production sectors were allowed to participate in the study and those who
agreed, signed a consent form before entering the study.
Outcome measures
Despite the intervention had been applied in the production sectors, the outcomes were
evaluated at an individual level.
Primary outcome
The increase of costs caused by sickness absence is a major problem for industrial
organizations31,32
. That is why the primary outcome measure was absence from work due to
sick leave, assessed by the number of working hours lost due to symptom or disease of the
musculoskeletal system and connective tissue (M Group International Classification of
Diseases, ICD-10).
The industry where the study was conducted registered daily the occurrence of
workers who had sick note. The record was done by the human resources sector and includes
information about the medical certificate's reason (ICD-10) and the number of days lost. All
information has been obtained by electronic report, extracted by a person who was unaware of
the study and group participants.
Secondary outcomes
The secondary outcome measures were musculoskeletal symptoms, risk factors for
musculoskeletal pain and disorders, psychosocial factors and fatigue, general health and
productivity.
Musculoskeletal symptoms (pain, tingling, or numbness) was assessed using the
Nordic Musculoskeletal Questionnaire (QNSO). The workers answered yes or no in relation
to musculoskeletal symptoms they have experienced during the past 12 months33
. Data shows
prevalence of WMSDs in the neck, shoulders, elbows, hands, upper back, low back, hips,
knees and feet.
Risk factors for musculoskeletal pain and disorders were assessed by the perception of
workers against risk factors that may contribute to the development of musculoskeletal
complaints through the Job Factors Questionnaire. This instrument presents a descriptive list
of 15 risk factors that should be classified on a scale of zero to ten, indicating the worker’s
perception about how much each factor contributed to the occurrence of WMSDs symptoms,
with zero meaning "no problem" and ten indicating the "largest possible problem"34
.
The perception of workers against psychosocial factors and stress, resulting in fatigue
induced by work, were evaluated through the Scale of Need for Recovery35
. This Likert scale
has 11 questions and possible answers of numbers up to 4 (0=never, 1=sometimes, 2=often,
and 3=always). The answer “always” indicates an unfavorable situation and receives 3 scores,
with the exception of item 4, which features reverse scoring. The total score is obtained by
summing the final, transformed by rule of three direct, on a scale of 0 (minimum) to 100
(maximum). Higher scores indicate greater frequency and intensity of symptoms related to
fatigue and stress and, consequently, greater need for recovery36
.
Overall health status and quality of life was assessed by the World Health
Organization Quality of Life scale, abbreviated version (WHOQOL-BREF)36,37
. This self-
reported instrument contains 26 questions, divided into four areas: social, psychological,
physical, and environment. Each domain consists of questions whose answer scores range
between 1 and 536,37
. The averages of the issues and domains scores are converted to a scale
of 0 to 10. Higher score indicates better quality of life38
.
A single item WHO General Health Questionnaire and Performance at Work [27]
measured productivity. Participants assigned a score (0–10) for their labor productivity. The
cost-effectiveness of interventions was calculated according to the cost effectiveness
incremental. For this, we considered the cost required to conduct ergonomic guidelines and
cost guidelines in conjunction with job rotation. These values are divided by the time lost
from work1.
The primary outcome was assessed at baseline and three-months follow-up. The
secondary outcomes were assessed at baseline and 12-months after the randomization, by a
blinded assessor. In the study, it was impossible to blind workers and ergonomists because of
the nature of the intervention used. To test blinding, after assessment of outcomes, the
worker’s assessment researcher and noted his opinion as to the type of intervention received
by workers.
Statistical Analysis
The statistical analysis was conducted on an intention-to-treat basis which is
participants were analyzed in the groups to which they were randomly allocated. The Shapiro-
Wilk test was used to assess the normality of the data. Descriptive statistics were used in the
analysis of characteristics of the participants. The chi-square test was used to evaluate the
blinding of the assessor by comparing the randomization codes and the evaluator. The
difference between the groups and their respective confidence intervals was calculated using
linear mixed models by using group, time and group-versus-time interaction terms [30]. The
within group difference was calculated using the Student paired t test for dependent samples.
The difference between the groups for nominal data was calculated using the McNemar's test.
The significance level is 5%. The statistical program SPSS 23.0 was used for all analyses.
Results
Participants Flow and Loss to follow-up
A total of 10 departments (N=1987 workers) were assessed for eligibility and four
departments (N=581 workers) were included. All workers were invited to participate, but 136
1 Cost-effectiveness data will not appear on this version but will be included for article
submission.
declined. Besides that, prior to randomization, 330 workers were dismissal due to business
reasons. At the final, after randomization, two departments (N=266 workers) were allocated
to the intervention group and two (N=225) to the control group. Figure 1 presents a summary
of enrollment, intervention allocation, follow-up and data analysis of departments and
participant in this trial.
At 12 month-intervention, workers were dismissal due to business reasons (N=136
workers) and 32 workers from JRP not finalized the intervention by determination of the
company's management. Then, the loss to follow-up on the primary and secondary outcomes
measure was 25.2% in the intervention group and 26.2% in the control group. Anyway, the
total of participants meets the sample calculation, which required the 232 workers.
Figure 1 – Participant’s enrollment, intervention allocation, follow-up, and data analysis.
Sociodemographic characteristics
The participants were predominantly female (77.8%) and had a mean time in the
company of 50 months. The mean number of working hours lost due to sick leave by
musculoskeletal injuries was 27.2. At baseline, no meaningful differences between the groups
for demographic characteristics were found. The demographic characteristics of the workers
in the intervention group and the control group are presented in Table 1.
Table 1- Sociodemographic variables for both groups (control and intervention) and all
workers (n=491)
Effects on the number of working hours lost due to sick leave by musculoskeletal injuries
At 12-month follow-up both groups showed a progressive increase in the number of
working hours lost due to sick leave by musculoskeletal injuries. No significant differences
between groups were observed for any follow-up. In the within-group comparison, the results
Table 1- Sociodemographic variables for both groups (control and intervention) and all
workers (n=491)
Variable Control
(N=225)
Intervention
(N=266)
Sex
Male 30 (13.3)
72 (21.1)
Female 195 (86.7)
194 (72.9)
Age (years) 32.5 (9.0)
28.4 (7.8)
Marital status
Single 158 (70.2)
211 (79.3)
Married 60 (26.7)
49 (18.4)
Divorced 2 (0.9)
0 (0.0)
Widowed 3 (1.3)
3 (1.1)
Not mentioned 2 (0.9)
3 (1.1)
Education status
Illiterate 17 (7.6)
12 (4.5)
Elementary degree 67 (29.8)
58 (21.8)
High School 130 (57.8)
183 (68.8)
University 8 (3.6)
11 (4.1)
Not mentioned 3 (1.3)
2 (0.8)
Employment time in the company (months)
56.9 (44.3)
49.6 (43.2)
showed a significant difference for the 6-month, 9-month and 12-month follow-up at the
intervention group and for the 9-month and 12-month follow-up at the control group (Table
2).
Table 2 – Description of primary outcome for both groups (control and job rotation) and all
workers (n=491)
Effects on musculoskeletal symptoms
The table 3 shows that the prevalence of workers with symptoms of pain or
musculoskeletal discomfort were decreased in almost body regions for both groups after 12
months of intervention in both groups. There was a significant reduction of symptoms only
for wrists and hands symptoms.
Primary
Outcome
Groups Unadjusted Mean (SD)
Unadjusted Within-Group
Differences (Baseline minus Follow-up)
Between-Group
Adjusted Mean
Differences
(Intervention
minus Control) Intervention
(N=266)
Control
(N=225)
Intervention
(N=266)
Control
(N=225)
Absence from work due to sick leave (Hrs.)
Baseline 20.3 (54.8)
34.2 (79.4)
3 month
a 27.1 (57.34)
34.0 (62.6)
0.3
(-0.1 to 0.6)
0.0
(-0.5 to 0.5)
7.0
(-12.4 to 26.4)
6 months
a 37.2 (103.7)
43.5 (73.5)
0.7b
(0.2 to 1.2)
0.4
(-0.1 to 0.9)
7.6
(-11.8 to 27.0)
9 months
a 45.7 (107.2)
49.3 (99.0)
1.1b
(0.5 to 1.6)
0.7b
(0.0 to 1.2)
10.3
(-9.1 to 29.7)
12 months
a 49.2 (110.5)
68.7 (157.7)
1.2
(0.3 to 0.7) 1.4
b
(0.6 to 2.2) -5.6
(-25.0 to 13.8)
Hrs. = Hours a Missing data: Intervention group (n=67) and Control group (n=59)
b Significant difference within groups (P < 0.05)
Table 3 - Description of musculoskeletal symptoms outcome for both groups (control and job
rotation) and all workers (n=491)
a Significant difference within groups (P < 0.05)
Effects of self-perception on the musculoskeletal pain risk factors, fatigue and psychosocial
factors and general health
Table 4 shows the intervention effects on the four outcomes. Three of these are related
to the effects that JRP on self-perception the musculoskeletal pain risk factors, fatigue and
psychosocial risk factors and general health at the baseline and after 12 months of
intervention. The results showed that JPR was not able to improve the self-perception workers
to the risks factors and their general health. Rather, workers had a worse perception for all
results. On the contrary, workers had a worse perception for all these outcomes. No
significant differences between groups were observed for any outcome. However, in the
within-groups comparison, there was a significant difference for almost all outcomes for both
groups. The only exception was the perception about psychosocial factors and fatigue in the
intervention group.
Secondary Outcomes
Groups Frequency
P-Value Month 0
Month 12
Intervention (N=266)
Control (N=225)
Intervention (N=266)
Control (N=225)
Musculoskeletal symptoms (%)
Neck
98 (36.8)
89 (39.6)
70 (26.3)
73 (32.4) 0.29
Shoulders 145 (54.5)
120 (53.3)
112 (42.1)
97 (43.1) 0.11
Upper back 120 (45.1)
94 (41.8)
77 (28.9)
83 (36.9) 0.85
Elbows
18 (6.8)
18 (8.0)
12 (4.5)
23 (10.2) 0.12
Wrists/Hands 101 (38.0)
88 (39.1)
79 (29.7)
79 (35.1) 0.04a
Low back 104 (39.1)
84 (37.3)
65 (24.4)
76 (33.8) 0.73
Hips/Thighs 30 (11.3)
36 (16.0)
22 (8.3)
28 (12.4) 0.65
Knees
50 (18.8)
42 (18.7)
36 (13.5)
48 (21.3) 0.19
Ankles/Fit 75 (28.2)
55 (24.4)
43 (16.2)
58 (25.8) 0.52
100
Table 4 – Description of secondary outcomes for both groups (control and job rotation) and all workers (n=491)
Secondary
Outcomes
Groups Unadjusted Mean (SD)
Unadjusted Within-Group
Differences
(Baseline minus Follow-up)a
Between-Group
Adjusted Mean
Differences
(Intervention
minus Control) Month 0
Month 12
Intervention
(N=266)
Control
(N=225)
Intervention
(N=266)
Control
(N=225)
Intervention
(N=266)
Control
(N=225)
Musculoskeletal pain
risk factors (0-150) 72.5 (37.9)
77.9 (36.3)
84.1 (33.1)
85.6 (33.9)
11.9b
(6.2 to 17.6)
6.3b
(1.0 to 11.7)
4.6
(-3.1 to 12.2)
Psychosocial factors
and fatigue (0-100) 38.7 (18.1)
37.3 (18.4)
39.3 (18.0)
40.2 (18.2)
1.9
(-0.6 to 4.8)
2.7b
(0.1 to 5.3) -1.5
(-4.9 to 2.0)
General health (0-100)
Physical domain
64.2 (15.5)
62.3 (15.5)
58.0 (13.6)
58.2 (14.3)
-7.0b
(-9.7 to -4.2)
-4.3b
(-6.9 to -1.7) -2.2
(-5.8 to 1.4)
Psychological
domain 68.7 (15.5)
67.8 (15.2)
64.5 (12.3)
63.5 (12.5)
-5.1
b
(-7.6 to -2.6)
-4.5b
(-6.8 to -2.2) -0.8
(-3.4 to 3.2)
Social domain
68.4 (18.8)
66.0 (20.0)
61.7 (15.6)
60.9 (14.9)
-6.7b
(-9.9 to -3.4)
-5.6b
(-8.9 to -3.4) -1.5
(-5.9 to 2.9)
Environmental
domain 50.2 (13.7)
46.3 (15.2)
46.1 (10.4)
42.2 (13.4)
-4.4
b
(-6.9 to -1.9)
-3.8b
(-6.3 to -1.2) -0.7
(-3.5 to 3.3)
Productivity (0-10) 8.3 (1.6)
8.4 (1.6)
8.1 (1.7)
7.5 (2.6)
-0.4b
(-0.1 to -0.6)
-0.9b
(-1.3 to -0.6) 0.99
(-0.85 to 1.05)
a Missing data: Intervention group (n=67) and Control group (n=59)
b Significant difference within groups (P < 0.05)
Effects on productivity
Table 4 also shows the effects of JRP on productivity. During the 12 months, there
was a decreased of productivity with a significant difference for both groups, in the within-
group comparison. However, in between group, no significant differences were found.
Blinding
The evaluator blinding was confirmed by the number of hits to intervention group
(58.3 %) and to control group (50.1 %) (p >0.05).
Discussion
This study is the first randomized controlled trial that aimed evaluates the
effectiveness of JRP designed to prevent and control work-related musculoskeletal disorders.
It was conducted with a large population of industrial workers during twelve months. After
the intervention, the job rotation was not more effective than the control group for any of the
assessed outcomes. This means that it was not effective in reducing the number of working
hours lost due to sick leave by musculoskeletal injuries; decreasing the prevalence of
musculoskeletal symptoms; and, improve self-perception musculoskeletal pain risk factors,
psychosocial risk factors and productivity. Only the prevalence of wrists and hands
musculoskeletal symptoms had a significant improvement after de job rotation.
Two recent systematic reviews11,23
had already demonstrated two important findings
that compromised the confirmation job rotation effectiveness. Firstly, the quality of evidence
is very low39
because no randomized clinical trial has been found and most studies have
longitudinal and cross-sectional study designs with methodological quality varying between
fair and poor23
. Secondly, the reviews concluded that the effectiveness of job rotation is
conflicting and inconsistent11,23
. These studies have found positive and negative results for job
rotation effects on WMSD. For example, Guimarães et al. (2012)40
showed a significant
reduction in the occurrence musculoskeletal injuries, absenteeism, turnover, rework, and
spoilage in workers who performed job rotation for 3.5 years. Roquelaure et al. (1997)41
found a positive association between job rotation and the carpal tunnel syndrome prevention.
But, on the contrary, Fredriksson et al. (2001)42
founded that physical workload and
frequency of WMSD’s occurrence increased significantly in the group of workers who
performed job rotation schedules in line system 42
. Similar results were found by Balogh et al.
(2006)43
and Sato and Coury (2009)17
. However, these studies the job rotation was not the
main intervention assessed, resulting in various confounders to the measured outcomes.
Unlikely the studies mentioned our study was adequately planned job rotation for
mitigating continuous exposure to risk factors for musculoskeletal disorders40,44
. Therefore,
we evaluated the job characteristics and production method and measured the biomechanical
and psychosocial risk exposure level in all tasks included; we created the schedule based on
criteria and parameters suggested by the scientific literature; managers was involved and
accepted to realize the JRT; all workers were trained; and, the tasks were easy to perform.
Also, it is important to mention that the JRP deployment process has been well accepted by
managers and by most workers during the 12 months specified in the study design. Perhaps
it's due to the fact that this industry has an ergonomics program for 10 years. This program
includes ergonomic design, participatory ergonomic, ergonomic guidelines and adjustments
and rest breaks at work. Despite all this, our trial failed to demonstrate the effectiveness of the
JRP in reducing the number of working hours lost due to sick leave by musculoskeletal
injuries.
There are several possible explanations for our findings. The first explanation is
related to the primary outcome, which was chosen due to the cost caused by WMSDs and its
contribution to decision-making regarding the management of safety and health strategies. We
assumed that, if the job rotation were effective for to prevent and to control WMSDs, it would
be able to reduce the number of working hours lost due to sick leave. However, it seems that
this outcome may not be the most appropriate to measure the health effects promoted by
ergonomic strategies used for promoting work variability17,45,46
, because its represents a long-
term indicator. Furthermore, the number of hours of work lost due to sick leave may be
related to the worsening of musculoskeletal symptoms requiring greater number of days/hours
of absence from work1,47
. The second explanation is that the industry where the study was
conducted had never done job rotation before. Maybe, for this reason, the workers were not
interested in developing new skills, which is an important prerogative for the success of this
intervention48
. Another explanation is that the inclusion of tasks with high risk level in the
JRP may limit the positive effects of variability generated by this intervention.
The only outcome for which the job rotation had a significant improvement was the
prevalence of wrists and hands musculoskeletal symptoms. This finding agrees with
Roquelaure et al. (1997)41
and Klussmann et al.(2008)49
. The last one shows that the
prevalence of symptoms of the hand/wrist was influenced by frequency of job rotation49
. In
our study, this result may be related to the fact that the wrists/hands have had less exposure
time and greater variability, obtained by rotating between lifting and gripping or repetitive
tasks. Other body regions, such as the neck, shoulder and low back, had no adequate rest,
because its muscles were kept in static muscular contractions, although of rotation between
the different tasks.
Our study have several strengths of methodological issues, such as: cluster RCT study
design and its statistical power; recruitment of a large population as well as the inclusion of
workers from diverse task with different workloads; randomization by department which
minimizes possible contamination between workers from the intervention and control groups;
use of standardized questionnaires to measure study outcomes; and blinding of assessor. As a
result, our study findings can be generalized for work settings with characteristics similar to
those of this study (i.e. manufacturing industries with production layouts organized into lines
or cells, whose rhythm was not determined by machines and allowing switching between
tasks with different biomechanical demands and levels of risk for musculoskeletal pain and
disorders).
A limitation of this study was the changes in the trial design that was beyond the
control of researchers. Managers did not allow that the secondary outcomes follow-up were
collected every three months as described in the research project due to the time spend by
workers in answering the questionnaires. Then, the secondary outcomes follow-up was
collected only at the baseline and after the 12-month intervention. Managers also did not
allowed two of the tasks included in the intervention group (N = 32 employees) continue in
the study, since the workers boycotted the rotation, causing a negative effect on productivity.
However, all the statistical analysis was conducted on an intention-to-treat basis. This ensures
that non-compliance, protocol deviations, withdrawal, and anything that happens after
randomization may influence the results, resulting in overoptimistic estimates of the efficacy
of an intervention50
.
Another limitation was the considerable loss to follow-up rates on secondary
outcomes found after 12 months. Unfortunately, loss to follow-up is a common problem
among prevention studies51
, particularly in industrial settings where determinations of
organizations may affect the study conduction52
. However, our loss to follow-up rates was
<30%, not affecting the ability to draw firm conclusions53
. Besides, the total of participants
exceeds the number of participants defined by sample size calculation.
In fact, based on the results of this study, it can be concluded that there was no
advantage of using JRP to decrease the number of working hours lost due to musculoskeletal
symptom or disease and to prevent and control musculoskeletal disorders. These results
challenge the theory that job rotation is a good organizational strategy for to prevent and
control musculoskeletal complaints, particularly, in work settings whose exposure level
cannot be lowered due to the characteristics of the job or through physical measures4.
However, it is needed to take care in translating the results to all manufacturing industries. It
is necessary to consider the specifics of the job, settings and organization preferences and
necessities. In practice, it is up to managers and occupational health professionals who
provide occupational health services in different companies decide about the use of job
rotation. For example, in this textile industry, the managers decided to continue performing
the job rotation, even after being informed of the results. They understand that the results of
this intervention were positive in many aspects, as the development of workers with multi-
tasking skills, monotony and boredom reduction and good acceptance of Labor Inspection
Organs.
Conclusion
After 12 months, the results of this large cluster randomized clinical trial showed that
job rotation was not more effective than the control group into decrease the number of
working hours lost due to musculoskeletal symptom or disease and to prevent and control
musculoskeletal disorders.
Other Information
Registration
This trial was prospectively registered at ClinicalTrials.gov, number NCT01979731,
in November 3, 2013
Protocol
The methods of the study were more detailed in a published protocol, available with
full text of this article at BMC Musculoskeletal Disorders24
.
Funding
This study is supported by the National Counsel of Technological and Scientific
Development (CNPq), Brazil (473651/2013-0). The founders had no interference in any step
of this trial.
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2011;2(3):109-112.
51. Galea S, Tracy M. Participation rates in epidemiologic studies. Annals of
epidemiology. 2007;17(9):643-653.
52. Schelvis RM, Oude Hengel KM, Burdorf A, Blatter BM, Strijk JE, van der Beek AJ.
Evaluation of occupational health interventions using a randomized controlled trial:
challenges and alternative research designs. Scand. J. Work Environ. Health. 2015;41(5):491-
503.
53. Higgins J, Green S. Cochrane Handbook for Systematic Reviews of Interventions
version 5.0.1 The Cochrane Collaboration 2008: The Cochrane Collaboration; 2008.
113
CAPÍTULO 5
Desdobramentos do Estudo – Lições Aprendidas
Execução do projeto de pesquisa
A fase inicial do projeto de pesquisa, cujos métodos foram apresentados no capítulo 2,
teve início no período de junho a setembro de 2013. Neste momento, foram organizadas
diversas reuniões com os gestores de produção, incluindo: gerente, coordenadores,
supervisores e líderes de produção. O objetivo destas reuniões foi apresentar a proposta do
estudo e os métodos de implantação do rodízio, e com base nestas informações, definir os
setores que poderiam participar do estudo. Dentre os setores de produção da indústria têxtil
em questão, apenas 4 atendiam aos critérios de inclusão do estudo, ou seja, eram setores com
linhas de produção cujo ritmo não é determinado por máquinas o que permitiam a alternância
entre tarefas de diferentes solicitações biomecânicas e níveis de exposição. Uma vez definido
isto, os gestores explicaram aos pesquisadores quais eram as especificidades de cada tarefa; as
metas de produção; a autonomia de cada operação (técnicas, uso de máquinas, equipamentos
e ferramentas, e ritmo de trabalho); e, o nível de treinamento necessário para aptidão do
trabalhador.
Em seguida, realizou-se uma análise biomecânica com o objetivo de identificar: (1) a
principal demanda física (manuseio de materiais, repetição de movimentos, postura estática);
(2) a postura predominantemente adotada para a realização da tarefa (sentada, ajoelhada, em
pé, andando); (3) as regiões corporais de maior sobrecarga (ombros, cotovelos, punhos, mãos,
coluna); e, (4) o nível de intensidade da exposição (baixo, moderado, alto ou muito alto). O
nível de intensidade da exposição ao risco biomecânico foi avaliado pelos instrumentos
QEC1, REBA
2.
Todas as informações fornecidas pelos gestores e os resultados das análises
ergonômicas foram utilizados para construção da escala de rodízio. A proposta final desta
escala foi apresentada aos gestores juntamente com um plano de trabalho a ser cumprido na
implantação e acompanhamento do programa de rodízio de função. Por fim, mediante a
aprovação dos gerentes, o programa foi implantado em fevereiro de 2014.
114
Nos dois primeiros meses, o programa de rodízio de função foi monitorado
diariamente por um dos pesquisadores. Durante este período, algumas barreiras foram
encontradas. A primeira barreira decorreu da resistência dos trabalhadores alocados em duas
tarefas produtivas do setor de acabamento de peças sem costura (revisão de peças sem costura
e separação de peças sem costura – N=32 trabalhadores). De acordo com o planejamento
previsto, os trabalhadores destas tarefas fariam o rodízio entre si, alternando entre diferentes
níveis de exposição. Isto porque, a tarefa de revisão possuia alto nível de exposição ao risco
biomecânico em razão da postura e frequência de movimentos realizados, uso de força e
demanda visual requeridos para a inspeção da qualidade do produto. Já a tarefa separação de
peças (por tipo de produto, cor e tamanho) era caracterizada por movimentos neutros em
região de coluna cervical, membros superiores e coluna lombar, possuindo baixo nível de
exposição. Desta forma, considerando os diferentes riscos biomecânicos a alternância entre
estas tarefas seria perfeita devido a variabilidade existente entre elas. Contudo, os
trabalhadores da tarefa de separação não quiseram realizar a tarefa de revisão, o que refletiu
negativamente na produtividade. Com isso, os gerentes da indústria solicitaram que o
programa de rodízio fosse descontinuado para estas duas tarefas.
A segunda barreira encontrada foi a demissão coletiva de 330 trabalhadores decorrente
da redução de vendas e, consequentemente, da necessidade de redução de custos operacionais.
Felizmente, a demissão aconteceu no mês de novembro de 2013, antes da implantação do
programa de rodízio; e, apesar ter reduzido número da amostra inicial, não afetou o número
de trabalhadores previsto pelo cálculo amostral.
A necessidade de mudar o intervalo de seguimento para avaliar os desfechos
secundários foi a terceira e mais importante barreira. Isso porque, incialmente, o projeto
contemplava 4 coletas com intervalos de seguimentos de três meses. Porém, por decisão dos
gestores a coleta de dados aconteceu somente em dois momentos: no baseline e após os 12
meses de intervenção. Isto aconteceu em razão do tempo utilizado para responder os
questionários (em média 50-60 minutos), o que impactou na dinâmica dos setores de
produção.
Apesar destas ocorrências, o projeto foi cumprido sem problemas em todos os seus
objetivos. O programa de rodízio de função foi adequadamente planejado para promover a
redução da exposição contínua a fatores de risco que contribuem para o desenvolvimento de
distúrbios músculoesqueléticos. Para tanto, avaliamos as características do trabalho e dos
métodos de produção; mensuramos o nível de exposição ao risco biomecânico e psicossocial;
criamos uma escala de alternância com base em critérios e parâmetros sugeridos pela
115
literatura científica; envolvemos gestores e trabalhadores no processo de implantação e
treinamento das tarefas. A fácil implantação do programa de rodízio de função pode estar
relacionada ao fato de que esta indústria já possuia um programa de ergonomia há mais de 10
anos, que incluia: ergonomia participativa, intervenções fiísicas com redesenho dos postos de
trabalho, orientações ergonômicas e pausas no trabalho.
Lições Aprendidas
A fase de implantação do rodízio, nos fez compreender a necessidade de discutir
tópicos relevantes para o uso e compreenssão desta intervenção, apesar destes não terem sido
objetivos iniciais do estudo. Um deles se refere à tópicos relacionados a análise qualitativa
da implantação do rodízio de função na indústria têxtil. Isto porque identificamos na prática,
que a implantação da proposta (ideal), não é simples e pode não ser tão efetiva quanto vem
sendo descrita. Alguns obstáculos dificultam implantação, tais como: características da tarefa
(organização do trabalho, espaço físico e número de trabalhadores), convicção dos gestores
sobre a importância do rodízio e aceitação dos trabalhadores em realizá-lo
3. A aceitação de
alguns trabalhadores em alternar entre tarefas de baixo para alto risco foi uma das maiores
dificuldades encontradas em nosso estudo. Consideramos a necessidade de novos estudos que
incluam a análise de fatores individuais e características psicossociais dos trabalhadores como
parâmetro para o planejamento do rodízio.
Outro tópico importante a ser discutido são os métodos de análise do risco
biomecânico, utilizados para auxiliar no planejamento do rodízio e assegurar que a
alternância entre tarefas e níveis de exposição resultem na redução dos níveis de estresse
físico e cognitivo para os trabalhadores. Isto porque, o planejamento inadequado do rodízio
não só torna a intervenção ineficaz, como pode resultar em aumento dos níveis de exposição
(3). Assim, buscando compreender um pouco mais sobre este tópico, os pesquisadores
propuseram um estudo que teve como objetivo comparar dois métodos observacionais de
análise do risco biomecânico usados para definir uma proposta de rodízio de função. Os
resultados mostraram que: (1) a concordância entre os métodos REBA e QEC foi baixa,
quando se considera a pontuação total dos instrumentos; e, que (2) o uso de escores por
segmento corporal, além de outros critérios qualitativos podem ajudar nesta definição. Em
nosso ensaio clínico, a esclada de alternância de rodízio foi definida considerando a
pontuação dos instrumentos de análise de risco e alguns outros aspectos, tais como: ritmo de
116
trabalho, tempo de ciclo, principal demanda da tarefa e percepção de esforço, avaliados por
meio da expertise de um dos pesquisadores.
Referências
1. David G, Woods V, Li G, Buckle P. The development of the Quick Exposure Check
(QEC) for assessing exposure to risk factors for work-related musculoskeletal disorders. Appl
Ergon. . 2008; 39(1):57-69.
2. McAtamney L, Hignett S. REBA: a rapid entire body assessment method for
investigating work related musculoskeletal disorders. Proceedings of the Ergonomics Society
of Australia,1995.
3. Guimaraes LB, Anzanello MJ, Renner JS. A learning curve-based method to
implement multifunctional work teams in the Brazilian footwear sector. Appl Ergon. 2012;
43(3):541-7.
117
CAPÍTULO 6
Considerações Finais
Os objetivos desta tese de doutorado foram: (1) avaliar, por meio de uma revisão
sistemática, a eficácia do rodízio como estratégia de controle de risco e doenças e identificar
os parâmetros utilizados para organizar as escalas de rodízio nas indústrias de manufatura, (2)
reelaborar uma proposta de rodizio que pudesse evidenciar sua efetividade e, (3) avaliar, o
efeito do rodízio de função na prevenção dos distúrbios musculoesqueléticos em
trabalhadores industriais, por meio de um estudo clínico controlado e randomizado por
cluster.
Idealização da Revisão Sistemática, Conclusões e Desdobramentos
A revisão sistemática foi realizada após a idealização do projeto de pesquisa proposto
para avaliar a efetividade do rodízio de função como estratégia de prevenção aos distúrbios
musculoesqueléticos. A revisão, portanto, partiu da necessidade de compreender os critérios
utilizados para criação, as etapas de implantação, bem como escalas de organização do
rodízio, bem como analisar, mais criticamente, e concluir a razão para qual das divergências
dos efeitos. Isto porque, os artigos utilizados para construção do projeto de pesquisa não
respondiam a muitos dos questionamentos gerados. A revisão respondeu então, a alguns dos
questionamentos, mas há muito o que compreender ainda sobre os efeitos do rodízio de
função para prevenção e controle das lesões musculoesqueléticas.
Assim, o delineamento da revisão sistemática foi feito em outubro de 2013. A
proposta inicial foi a de realizar uma revisão ampla, incluindo as diferentes abordagens do
rodízio em diferentes populações de trabalhadores. No entanto, após algumas discussões,
optou-se por estudar o rodízio apenas em indústrias de manufatura, uma vez que este tem sido
o foco de pesquisa dos autores. Os objetivos da revisão sistemática foram: (1) sintetizar
evidências relacionadas a efetividade do rodízio de função utilizado como estratégia de
controle e prevenção dos distúrbios musculoesqueléticos e, (2) identificar os parâmetros
utilizados para organizar as escalas de rodízio nas indústrias de manufatura.
118
Os resultados gerais da revisão sistemática nos levaram a concluir que a evidência do
rodízio como estratégia para prevenção e controle de distúrbios osteomusculares é bastante
limitada, principalmente em razão da qualidade metodológica dos estudos e da ausência de
ensaios controlados randomizados. Se por um lado, este achado reforça a necessidade de
realização de novos estudos com melhor qualidade metodológica, por outro ele nos leva a
refletir sobre as dificuldades em realizar estudos que avaliam a efetividade de alguma
intervenção ergonômica em indústrias. Algumas destas dificuldades são: (1) a influência de
outros fatores da organização, que não podem ser controlados pelos pesquisadores, sobre a
intervenção testada; (2) barreiras para análises estatísticas, em razão do número de
trabalhadores por tarefa ou setor; (3) aceitação dos trabalhadores, dentre outros1,2
.
Outra conclusão é que os parâmetros para organização do rodizio descritos na revisão
sistemática possuem grande variabilidade de critérios, incluindo: postura e movimentos,
demandas cognitivas, estratégias e políticas da indústria, habilidades de aprendizagem,
responsabilidade, entre outros e são fortemente influenciados pelos modelos de produção,
organização e execução do rodízio de função. A maioria dos estudos utilizou ambos
parâmetros biomecânicos e organizacionais para a criação de suas escalas que contemplavam
intervalos de alternância variando entre uma ou duas horas. No entanto, nenhum deles
descrevem como a escala de rodízio foi planejada e o quanto estes parâmetros foram
determinantes para a efetividade do rodízio.
Por fim, pudemos observar que muitos estudos propõe a utilização de equações
matemáticas e algoritmos para auxiliar no planejamento das escalas de rodízio. Porém,
nenhuma destes foram testados na prática, o que dificulta a avaliação de sua efetividade.
Diante disso, verifica-se a necessidade de estudos que avaliem a efetividade das equações e
algoritmos para planejamento do rodízio de função. Este inclusive é um dos objetivos para
futuros estudos do nosso grupo, que prevê a elaboração e teste de uma equação matemática
que integre os critérios mencionados na literatura, incluindo principalmente a análise da
demanda específica de cada indústria e os fatores pessoais e psicossociais dos trabalhadores.
Diante do exposto, refletir sobre os resultados desta revisão e sobre as dificuldades
enfrentadas para se realizar um ensaio clínico em ambientes ocupacionais, nos faz
compreender a relevância do ensaio clínico conduzido por nosso grupo de pesquisa, para
avaliar a efetividade do rodízio de função em trabalhadores industriais. Nós acreditamos e
esperamos fortemente que seus resultados possam contribuir para a tomada de decisão de
gestores e profissionais de saúde e segurança que prestam serviços para as indústrias.
119
Idealização do Ensaio Clínico, Conclusões e Desdobramentos
O estudo do efeito do rodízio de função na prevenção dos distúrbios
musculoesqueléticos em trabalhadores industriais por meio de ensaio clinico “nasceu” de uma
demanda da indústria estudada. Esta indústria possui um programa de ergonomia que, há
algum tempo vinha recomendando sem sucesso, a utilização de rodízio de funções e pausas
programadas como estratégias para prevenção e controle dos distúrbios musculoesqueléticos.
A decisão da empresa por implantar o rodízio de função se deu em razão do número de
atestados decorrentes destes distúrbios e das frequentes solicitações dos órgãos fiscalizadores
do meio ambiente e trabalho. Diante desta oportunidade, um dos pesquisadores deste estudo
propôs que a implantação do programa de rodízio de função cumprisse todos os critérios
propostos pela literatura científica e fosse testado no desenho de um ensaio clínico controlado.
A proposta foi discutida, aceita e implantada em 2013/2014.
Durante a execução do estudo, enfrentamos algumas dificuldades, já descritas no
capítulo 5. Mas apesar disso, o projeto foi cumprido sem problemas em todos os seus
objetivos. Ao final, os resultados revelaram o programa de rodízio de função não foi mais
eficaz do que o grupo controle para a redução do número de horas de trabalho perdidos em
razão de atestados médicos por doenças musculoesqueléticas. Em outras palavras, o programa
de rodízio de função não foi efetivo em prevenir e controlar a ocorrência de distúrbios
osteomusculares em trabalhadores industriais. No entanto, é necessário tomar cuidado ao
transpor os resultados para todas as indústrias, pois é preciso considerar as particularidades de
cada organização.
O processo de implantação do rodízio na indústria têxtil fez com que os pesquisadores
considerassem a possibilidade de realizar futuros estudos que de identifiquem as melhores
ferramentas e critérios para análise de riscos biomecânicos, quando se deseja propor um
rodízio de função como estratégia de prevenção aos distúrbios musculoesqueléticos. Criar e
testar as propriedades de medida de um instrumento de análise de risco específica para o
planejamento do rodízio, coerente com as necessidades específicas de cada indústria, também
seria uma proposta interessante.
Os desdobramentos da fase de implantação do rodízio possibilitaram a produção
científica de dois resumos que apresentados em formato oral no congresso Work, Stress and
Health Conference in Atlanta, nos Estados Unidos, em maio de 2015. Além disso, a partir dos
120
resultados da implantação do rodízio, idealizou-se um projeto de iniciação científica. Este
projeto pretende verificar a concordância de parâmetros biomecânicos e organizacionais entre
um método observacional e uma equação de multicritérios desenvolvida por Diego-Mas et al3.
Referências
1. Dempsey PG. Effectiveness of ergonomics interventions to prevent musculoskeletal
disorders: Beware of what you ask. Int J Ind Ergon. 2007;37(2):169-73.
2. Schelvis RM, Oude HKM, Burdorf A, Blatter BM, Strijk JE, van der Beek AJ.
Evaluation of occupational health interventions using a randomized controlled trial:
challenges and alternative research designs. 2015;41(5):491-503.
3. Diego-Mas JA, Asensio-Cuesta S, Sanchez-Romero MA, Artacho-Ramirez MA. A
multi-criteria genetic algorithm for the generation of job rotation schedules. Int J Ind Ergon.
2009; 39(1):23-33.
ANEXOS E APÊNDICES
www.unicid.edu.brR.
Cesário Galeno, 448/475
CEP- 03071 000 - São
Paulo SP
Tel: 55 11 2178 1200
DECLA RACÃ O
Declaro para os devidos fins que o Protocolo CAAE 18170313.5.0000.0064 -
"Efeitos do rodízio da tarefa na prevenção de distúrbios osteomusculares
relacionados ao trabalho: um estudo clínico randomizado por
agrupamento", pesquisadora responsável: Rosimeire Simprini Padula foi
submetido ao Comitê de Ética em Pesquisa da Universidade Cidade de São
Paulo - UNICID e aprovado no dia 12 de junho de 2013 .
São Paulo, 25 de março de 2014.
do CEP da Unicid
UNICID
Universidade Cidade de S.Paulo
APENDICE 1
TERMO DE CONSENTIMENTO LIVRE E ESCLARECIDO
Eu, ___________________________________________________________, abaixo
assinado, tendo sido devidamente esclarecido sobre os objetivos, riscos e demais condições
que envolverão minha participação no Projeto de Pesquisa intitulado EFEITOS DO
RODÍZIO DE FUNÇÃO NA PREVENÇÃO DE DISTÚRBIOS OSTEOMUSCULARES
RELACIONADOS AO TRABALHO: UM ESTUDO CLÍNICO RANDOMIZADO
POR AGRUPAMENTO, coordenado pela Profa. Dra. Rosimeire Simprini Padula, declaro
que tenho total conhecimento dos direitos e das condições que me foram apresentadas e
asseguras, as quais passo a descrever:
1. A garantia de ser informado e de ter respondida qualquer pergunta ou esclarecimento à
dúvidas sobre os procedimentos, objetivos, decorrências e riscos referentes às situações da
pesquisa a que serei submetido;
2. A garantia de que não serei pessoalmente identificado, a despeito da publicação dos dados
genéricos do estudo, e que terei resguardada minha privacidade;
3. A liberdade de deixar de participar do estudo, a qualquer momento, sem qualquer ônus ou
constrangimento;
4. A garantia de que me será prestada informação regular durante o estudo, ainda que esta
possa influenciar a minha decisão de nele permanecer;
Declaro, ainda, que estou ciente e concordante com todas as condições que me foram
apresentadas e que, livremente, manifesto a minha vontade em participar do projeto supra-
mencionado.
__(cidade)_,_____ de __________________ de ________.
___________________________/______________
Nome do participante (legível)/RG
______________________
Assinatura do pesquisador
Anexo 1
Questionário Nórdico para Sintomas Osteomusculares
ANEXO 2
Job Factors Questionnaire
ANEXO 3
Escala de Necessidade de Descanso
ANEXO 4
Whooquol- Bref
Instruções
Este questionário é sobre como você se sente a respeito de sua qualidade de vida, saúde e outras
áreas de sua vida. Por favor responda a todas as questões. Se você não tem certeza sobre que
resposta dar em uma questão, por favor, escolha entre as alternativas a que lhe parece mais
apropriada. Esta, muitas vezes, poderá ser sua primeira escolha.
Por favor, tenha em mente seus valores, aspirações, prazeres e preocupações. Nós estamos
perguntando o que você acha de sua vida, tomando como como referência as duas últimas
semanas. Por exemplo, pensando nas últimas duas semanas, uma questão poderia ser:
Nada Muito pouco Médio Muito Completamente
Você recebe dos
outros o apoio de
que necessita?
1 2 3 4 5
Você deve circular o número que melhor corresponde ao quanto você recebe dos outros o apoio
de que necessita nestas últimas duas semanas. Portanto, você deve circular o número 4 se você
recebeu "muito" apoio ou você deve circular o número 1 se você não recebeu "nada" de apoio.
nada Muito pouco Médio muito Completamente
Você recebe dos
outros o apoio de
que necessita?
1 2 3 5
Por favor, leia cada questão, veja o que você acha e circule no número e lhe parece a melhor resposta.
nº muito ruim Ruim nem ruim nem
boa boa muito boa
1 Como você avaliaria sua
qualidade de vida? 1 2 3 4 5
nº
muito
insatisfeito Insatisfeito
nem satisfeito
nem
insatisfeito
satisfeito muito
satisfeito
2 Quão satisfeito(a) você
está com a sua saúde? 1 2 3 4 5
As questões seguintes são sobre o quanto você tem sentido algumas coisas nas últimas duas semanas.
nº nada muito pouco mais ou menos bastante extremamente
3
Em que medida você
acha que sua dor (física)
impede você de fazer o
que você precisa?
1 2 3 4 5
4
O quanto você precisa de
algum tratamento médico
para levar sua vida
diária?
1 2 3 4 5
5 O quanto você aproveita
a vida? 1 2 3 4 5
6
Em que medida você
acha que a sua vida tem
sentido?
1 2 3 4 5
7 O quanto você consegue
se concentrar? 1 2 3 4 5
8 Quão seguro(a) você se
sente em sua vida diária? 1 2 3 4 5
9
Quão saudável é o seu
ambiente físico (clima,
barulho, poluição,
atrativos)?
1 2 3 4 5
As questões seguintes perguntam sobre quão completamente você tem sentido ou é capaz de fazer certas
coisas nestas últimas duas semanas.
nº nada
muito
pouco médio muito
completame
nte
10
Você tem energia
suficiente para seu dia-a-
dia?
1 2 3 4 5
11 Você é capaz de aceitar
sua aparência física? 1 2 3 4 5
12
Você tem dinheiro
suficiente para satisfazer
suas necessidades?
1 2 3 4 5
13
Quão disponíveis para
você estão as
informações que precisa
no seu dia-a-dia?
1 2 3 4 5
14
Em que medida você tem
oportunidades de
atividade de lazer?
1 2 3 4 5
As questões seguintes perguntam sobre quão bem ou satisfeito você se sentiu a respeito de vários aspectos de
sua vida nas últimas duas semanas.
nº muito ruim ruim nem ruim
bom muito bom nem bom
15 Quão bem você é capaz
de se locomover? 1 2 3 4 5
nº muito
insatisfeito Insatisfeito
nem satisfeito
nem
insatisfeito
satisfeito Muito
satisfeito
16 Quão satisfeito(a) você
está com o seu sono? 1 2 3 4 5
17
Quão satisfeito(a) você
está com sua capacidade
de desempenhar as
atividades do seu dia-a-
dia?
1 2 3 4 5
18
Quão satisfeito(a) você
está com sua capacidade
para o trabalho?
1 2 3 4 5
19 Quão satisfeito(a) você
está consigo mesmo? 1 2 3 4 5
20
Quão satisfeito(a) você
está com suas relações
pessoais (amigos,
parentes, conhecidos,
colegas)?
1 2 3 4 5
21
Quão satisfeito(a) você
está com sua vida
sexual?
1 2 3 4 5
22
Quão satisfeito(a) você
está com o apoio que
recebe dos amigos?
1 2 3 4 5
23
Quão satisfeito(a) você
está com as condições do
local onde mora?
1 2 3 4 5
24
Quão satisfeito(a) você
está com o seu acesso
aos serviços de saúde?
1 2 3 4 5
25
Quão satisfeito(a) você
está com o seu meio de
transporte?
1 2 3 4 5
As questões seguintes referem-se a com que freqüência você sentiu ou experimentou certas coisas nas últimas
duas semanas.
nº nunca Algumas
vezes freqüentemente
muito
freqüentemente sempre
26
Com que freqüência você
tem sentimentos
negativos tais como mau
humor, desespero,
ansiedade, depressão?
1 2 3 4 5
ANEXO 6
Quick Exposure Check – Folha de avaliação
ANEXO 6 (Continuação)
Quick Exposure Check – Folha de pontuação
ANEXO 7
Rapid Entire Body Assessment – Folha de Avaliação
ANEXO 7 (Continuação)
Rapid Entire Body Assessment – Folha de Avaliação (Continuação)
ANEXO 7 (Continuação)
Rapid Entire Body Assessment – Folha de Pontuação
ANEXO 7 (Continuação)
Rapid Entire Body Assessment – Folha de Pontuação (Continuação)
Anexo 8
Normas de Publicação do periódico Applied Ergonomics para o artigo apresentado no
Capítulo 4
Article structure
Subdivision - numbered sections
Divide your article into clearly defined and numbered sections. Subsections should be numbered 1.1 (then 1.1.1,
1.1.2, ...), 1.2, etc. (the abstract is not included in section numbering). Use this numbering also for internal cross-
referencing: do not just refer to 'the text'. Any subsection may be given a brief heading. Each heading should
appear on its own separate line.
Introduction
State the objectives of the work and provide an adequate background, avoiding a detailed literature survey or a
summary of the results.
Material and methods
Provide sufficient detail to allow the work to be reproduced. Methods already published should be indicated by a
reference: only relevant modifications should be described.
Theory/calculation
A Theory section should extend, not repeat, the background to the article already dealt with in the Introduction
and lay the foundation for further work. In contrast, a Calculation section represents a practical development
from a theoretical basis.
Results
Results should be clear and concise.
Discussion
This should explore the significance of the results of the work, not repeat them. A combined Results and
Discussion section is often appropriate. Avoid extensive citations and discussion of published literature.
Conclusions
The main conclusions of the study may be presented in a short Conclusions section, which may stand alone or
form a subsection of a Discussion or Results and Discussion section.
Appendices
If there is more than one appendix, they should be identified as A, B, etc. Formulae and equations in appendices
should be given separate numbering: Eq. (A.1), Eq. (A.2), etc.; in a subsequent appendix, Eq. (B.1) and so on.
Similarly for tables and figures: Table A.1; Fig. A.1, etc.
Essential title page information
• Title. Concise and informative. Titles are often used in information-retrieval systems. Avoid abbreviations and
formulae where possible.
• Author names and affiliations. Where the family name may be ambiguous (e.g., a double name), please indicate
this clearly. Present the authors' affiliation addresses (where the actual work was done) below the names.
Indicate all affiliations with a lower-case superscript letter immediately after the author's name and in front of
the appropriate address. Provide the full postal address of each affiliation, including the country name and, if
available, the e-mail address of each author.
• Corresponding author. Clearly indicate who will handle correspondence at all stages of refereeing and
publication, also post-publication. Ensure that telephone and fax numbers (with country and area code) are
provided in addition to the e-mail address and the complete postal address. Contact details must be kept up to
date by the corresponding author.
• Present/permanent address. If an author has moved since the work described in the article was done, or was
visiting at the time, a 'Present address' (or 'Permanent address') may be indicated as a footnote to that author's
name. The address at which the author actually did the work must be retained as the main, affiliation address.
Superscript Arabic numerals are used for such footnotes.
Abstract
A concise and factual abstract of between 100-150 words is required. The abstract should state briefly the
purpose of the research, the principal results and major conclusions. An abstract is often presented separately
from the article, so it must be able to stand alone. For this reason, References should be avoided, but if essential,
then cite the author(s) and year(s). Also, non-standard or uncommon abbreviations should be avoided, but if
essential they must be defined at their first mention in the abstract itself.
Graphical abstract
A Graphical abstract is optional and should summarize the contents of the article in a concise, pictorial form
designed to capture the attention of a wide readership online. Authors must provide images that clearly represent
the work described in the article. Graphical abstracts should be submitted as a separate file in the online
submission system. Image size: Please provide an image with a minimum of 531 × 1328 pixels (h × w) or
proportionally more. The image should be readable at a size of 5 × 13 cm using a regular screen resolution of 96
dpi. Preferred file types: TIFF, EPS, PDF or MS Office files. See http://www.elsevier.com/graphicalabstracts for
examples.
Authors can make use of Elsevier's free Graphical abstract check to ensure the best display of the research in
accordance with our technical requirements. 24-hour Graphical abstract check
Highlights
Highlights are mandatory for this journal. They consist of a short collection of bullet points that convey the core
findings of the article and should be submitted in a separate file in the online submission system. Please use
'Highlights' in the file name and include 3 to 5 bullet points (maximum 85 characters, including spaces, per bullet
point). See http://www.elsevier.com/highlights for examples.
Keywords
Immediately after the abstract, provide a maximum of 3 keywords, using American spelling and avoiding
general and plural terms and multiple concepts (avoid, for example, "and", "of"). Be sparing with abbreviations:
only abbreviations firmly established in the field may be eligible. These keywords will be used for indexing
purposes.
Abbreviations
Define abbreviations that are not standard in this field in a footnote to be placed on the first page of the article.
Such abbreviations that are unavoidable in the abstract must be defined at their first mention there, as well as in
the footnote. Ensure consistency of abbreviations throughout the article.
Acknowledgements
Collate acknowledgements in a separate section at the end of the article before the references and do not,
therefore, include them on the title page, as a footnote to the title or otherwise. List here those individuals who
provided help during the research (e.g., providing language help, writing assistance or proof reading the article,
etc.).
Math formulae
Present simple formulae in the line of normal text where possible and use the solidus (/) instead of a horizontal
line for small fractional terms, e.g., X/Y. In principle, variables are to be presented in italics. Powers of e are
often more conveniently denoted by exp. Number consecutively any equations that have to be displayed
separately from the text (if referred to explicitly in the text).
Footnotes
Footnotes should be used sparingly. Number them consecutively throughout the article, using superscript Arabic
numbers. Many wordprocessors build footnotes into the text, and this feature may be used. Should this not be the
case, indicate the position of footnotes in the text and present the footnotes themselves separately at the end of
the article. Do not include footnotes in the Reference list.
Table footnotes
Indicate each footnote in a table with a superscript lowercase letter.
Artwork
Electronic artwork
General points
• Make sure you use uniform lettering and sizing of your original artwork.
• Save text in illustrations as 'graphics' or enclose the font.
• Only use the following fonts in your illustrations: Arial, Courier, Times, Symbol.
• Number the illustrations according to their sequence in the text.
• Use a logical naming convention for your artwork files.
• Provide captions to illustrations separately.
• Produce images near to the desired size of the printed version.
• Submit each figure as a separate file.
A detailed guide on electronic artwork is available on our website:
http://www.elsevier.com/artworkinstructions
You are urged to visit this site; some excerpts from the detailed information are given here.
Formats
Regardless of the application used, when your electronic artwork is finalised, please 'save as' or convert the
images to one of the following formats (note the resolution requirements for line drawings, halftones, and
line/halftone combinations given below):
EPS: Vector drawings. Embed the font or save the text as 'graphics'.
TIFF: Color or grayscale photographs (halftones): always use a minimum of 300 dpi.
TIFF: Bitmapped line drawings: use a minimum of 1000 dpi.
TIFF: Combinations bitmapped line/half-tone (color or grayscale): a minimum of 500 dpi is required.
If your electronic artwork is created in a Microsoft Office application (Word, PowerPoint, Excel) then please
supply 'as is'.
Please do not:
• Supply files that are optimised for screen use (e.g., GIF, BMP, PICT, WPG); the resolution is too low;
• Supply files that are too low in resolution;
• Submit graphics that are disproportionately large for the content.
Color artwork
Please make sure that artwork files are in an acceptable format (TIFF, EPS or MS Office files) and with the
correct resolution. If, together with your accepted article, you submit usable color figures then Elsevier will
ensure, at no additional charge, that these figures will appear in color on the Web (e.g., ScienceDirect and other
sites) regardless of whether or not these illustrations are reproduced in color in the printed version. For color
reproduction in print, you will receive information regarding the costs from Elsevier after receipt of your
accepted article. Please indicate your preference for color: in print or on the Web only. For further information
on the preparation of electronic artwork, please see http://www.elsevier.com/artworkinstructions.
Please note: Because of technical complications which can arise by converting color figures to 'gray scale' (for
the printed version should you not opt for color in print) please submit in addition usable black and white
versions of all the color illustrations.
Figure captions
Ensure that each illustration has a caption. Supply captions separately, not attached to the figure. A caption
should comprise a brief title (not on the figure itself) and a description of the illustration. Keep text in the
illustrations themselves to a minimum but explain all symbols and abbreviations used.
Tables
Number tables consecutively in accordance with their appearance in the text. Place footnotes to tables below the
table body and indicate them with superscript lowercase letters. Avoid vertical rules. Be sparing in the use of
tables and ensure that the data presented in tables do not duplicate results described elsewhere in the article.
References
Citation in text
Please ensure that every reference cited in the text is also present in the reference list (and vice versa). Any
references cited in the abstract must be given in full. Unpublished results and personal communications are not
recommended in the reference list, but may be mentioned in the text. If these references are included in the
reference list they should follow the standard reference style of the journal and should include a substitution of
the publication date with either 'Unpublished results' or 'Personal communication' Citation of a reference as 'in
press' implies that the item has been accepted for publication.
Web references
As a minimum, the full URL should be given and the date when the reference was last accessed. Any further
information, if known (DOI, author names, dates, reference to a source publication, etc.), should also be given.
Web references can be listed separately (e.g., after the reference list) under a different heading if desired, or can
be included in the reference list.
References in a special issue
Please ensure that the words 'this issue' are added to any references in the list (and any citations in the text) to
other articles in the same Special Issue.
Reference management software
This journal has standard templates available in key reference management packages EndNote (
http://www.endnote.com/support/enstyles.asp) and Reference Manager (
http://refman.com/support/rmstyles.asp). Using plug-ins to wordprocessing packages, authors only need to select
the appropriate journal template when preparing their article and the list of references and citations to these will
be formatted according to the journal style which is described below.
Reference style
Text: All citations in the text should refer to:
1. Single author: the author's name (without initials, unless there is ambiguity) and the year of publication;
2. Two authors: both authors' names and the year of publication;
3. Three or more authors: first author's name followed by 'et al.' and the year of publication.
Citations may be made directly (or parenthetically). Groups of references should be listed first alphabetically,
then chronologically.
Examples: 'as demonstrated (Allan, 2000a, 2000b, 1999; Allan and Jones, 1999). Kramer et al. (2010) have
recently shown ....'
List: References should be arranged first alphabetically and then further sorted chronologically if necessary.
More than one reference from the same author(s) in the same year must be identified by the letters 'a', 'b', 'c', etc.,
placed after the year of publication.
Examples:
Reference to a journal publication:
Van der Geer, J., Hanraads, J.A.J., Lupton, R.A., 2010. The art of writing a scientific article. J. Sci. Commun.
163, 51–59.
Reference to a book:
Strunk Jr., W., White, E.B., 2000. The Elements of Style, fourth ed. Longman, New York.
Reference to a chapter in an edited book:
Mettam, G.R., Adams, L.B., 2009. How to prepare an electronic version of your article, in: Jones, B.S., Smith ,
R.Z. (Eds.), Introduction to the Electronic Age. E-Publishing Inc., New York, pp. 281–304.
Journal abbreviations source
Journal names should be abbreviated according to
Index Medicus journal abbreviations: http://www.nlm.nih.gov/tsd/serials/lji.html;
List of title word abbreviations: http://www.issn.org/2-22661-LTWA-online.php;
CAS (Chemical Abstracts Service): http://www.cas.org/sent.html.
Video data
Elsevier accepts video material and animation sequences to support and enhance your scientific research.
Authors who have video or animation files that they wish to submit with their article are strongly encouraged to
include these within the body of the article. This can be done in the same way as a figure or table by referring to
the video or animation content and noting in the body text where it should be placed. All submitted files should
be properly labeled so that they directly relate to the video file's content. In order to ensure that your video or
animation material is directly usable, please provide the files in one of our recommended file formats with a
preferred maximum size of 50 MB. Video and animation files supplied will be published online in the electronic
version of your article in Elsevier Web products, including ScienceDirect: http://www.sciencedirect.com. Please
supply 'stills' with your files: you can choose any frame from the video or animation or make a separate image.
These will be used instead of standard icons and will personalize the link to your video data. For more detailed
instructions please visit our video instruction pages at http://www.elsevier.com/artworkinstructions. Note: since
video and animation cannot be embedded in the print version of the journal, please provide text for both the
electronic and the print version for the portions of the article that refer to this content.
Supplementary data
Elsevier accepts electronic supplementary material to support and enhance your scientific research.
Supplementary files offer the author additional possibilities to publish supporting applications, high-resolution
images, background datasets, sound clips and more. Supplementary files supplied will be published online
alongside the electronic version of your article in Elsevier Web products, including ScienceDirect:
http://www.sciencedirect.com. In order to ensure that your submitted material is directly usable, please provide
the data in one of our recommended file formats. Authors should submit the material in electronic format
together with the article and supply a concise and descriptive caption for each file. For more detailed instructions
please visit our artwork instruction pages at http://www.elsevier.com/artworkinstructions.
Anexo 9
Normas de Publicação do periódico The Journal of the American Medical Association
(JAMA) para o artigo apresentado no Capítulo 5
All manuscripts must be submitted online via the JAMA online manuscript submission and
review system. At the time of submission, complete contact information (affiliation,
postal/mail address, email address, telephone and fax numbers) for the corresponding author
is required. First and last names, email addresses, and institutional affiliations of all coauthors
are also required. After the manuscript is submitted, the corresponding author will receive an
acknowledgment confirming receipt and a manuscript number. Authors will be able to track
the status of their manuscripts via the online system. After manuscript submission, all authors
of papers under consideration for publication will be sent a link to the Authorship Form to
complete and submit (see sample Authorship Form). See Manuscript Checklist, Manuscript
Preparation and Submission Requirements,1,2 and other details in these instructions for
additional requirements.
Cover Letter
Include a cover letter and complete contact information for the corresponding author
(affiliation, postal/mail address, email address, and telephone number) and whether the
authors have published or submitted any related papers from the same study (see
Duplicate/Previous Publication or Submission).
Manuscript Style
Manuscripts should be prepared in accordance with the AMA Manual of Style, 10th edition,1
and/or the ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of
Scholarly Work in Medical Journals.2
Manuscript Components
Include a title page, abstract, text, references, and as appropriate, figure legends, tables, and
figures. Start each of these sections on a new page, numbered consecutively, beginning with
the title page.
Recommended File Sizes
We recommend individual file sizes of no more than 500 kB and not exceeding 1 MB, with
the total size for all files not exceeding 5 MB (not including any video files).
Manuscript File Formats
For submission and review, please submit the manuscript as a Word document. Do not submit
your manuscript in PDF format.
Use 10-, 11-, or 12-point font size, double-space text, and leave right margins unjustified
(ragged).
Title Page
The title page should include a word count for text only (eg, not including abstract,
acknowledgment, or references) and the full names, highest academic degrees, and affiliations
of all authors. If an author’s affiliation has changed since the work was done, the new
affiliation also should be listed.
Title
Titles should be concise, specific, and informative and should contain the key points of the
work.1(p8) Please limit the length of titles to 150 characters for reports of research and other
major articles and 100 characters for Editorials, Viewpoints, Commentaries, and Letters. For
scientific manuscripts, overly general titles are not desirable and questions and declarative
sentences should be avoided. For reports of clinical trials, meta-analyses, and systematic
reviews, include the type of study as a subtitle (eg, A Randomized Clinical Trial, A Meta-
analysis, A Systematic Review). For reports of other types of research, do not include study
type or design in the title or subtitle.
Abstracts
Include a structured abstract of no more than 350 words for reports of original data, reviews,
and meta-analyses. Abstracts should be prepared in JAMA style—see instructions for
preparing abstracts below. For other major manuscripts, include an unstructured abstract of no
more than 200 words that summarizes the objective, main points, and conclusions of the
article. Abstracts are not required for Editorials, Viewpoints, and some special features.
All reports of original data, systematic reviews, and meta-analyses should be submitted with
structured abstracts as described below. No information should be reported in the abstract that
does not appear in the text of the manuscript.
Abstracts for Reports of Original Data:
Reports of original data should include an abstract of no more than 350 words using the
headings listed below. For brevity, parts of the abstract may be written as phrases rather than
complete sentences. Each section should include the following content:
Importance: The abstract should begin with a sentence or 2 explaining the clinical (or other)
importance of the study question.
Objective: State the precise objective or study question addressed in the report (eg, “To
determine whether…”). If more than 1 objective is addressed, the main objective should be
indicated and only key secondary objectives stated. If an a priori hypothesis was tested, it
should be stated.
Design: Describe the basic design of the study. State the years of the study and the duration of
follow-up. If applicable, include the name of the study (eg, the Framingham Heart Study). As
relevant, indicate whether observers were blinded to patient groupings, particularly for
subjective measurements.
Setting: Describe the study setting to assist readers to determine the applicability of the report
to other circumstances, for example, general community, a primary care or referral center,
private or institutional practice, or ambulatory or hospitalized care.
Participants: State the clinical disorders, important eligibility criteria, and key
sociodemographic features of patients. The numbers of participants and how they were
selected should be provided (see below), including the number of otherwise eligible
individuals who were approached but refused. If matching is used for comparison groups,
characteristics that are matched should be specified. In follow-up studies, the proportion of
participants who completed the study must be indicated. In intervention studies, the number
of patients withdrawn because of adverse effects should be given. For selection procedures,
these terms should be used, if appropriate: random sample (where random refers to a formal,
randomized selection in which all eligible individuals have a fixed and usually equal chance
of selection); population-based sample; referred sample; consecutive sample; volunteer
sample; convenience sample.
Note: the preceding 3 sections are usually combined for accepted papers during the editing
process as “Design, Setting, and Participants,” but for manuscript submission these sections
should be kept separate.
Intervention(s) for clinical trials or Exposure(s) for observational studies: The essential
features of any interventions, or exposures, should be described, including their method and
duration. The intervention, or exposure, should be named by its most common clinical name,
and nonproprietary drug names should be used.
Main Outcome(s) and Measure(s): Indicate the primary study outcome measurement(s) as
planned before data collection began. If the manuscript does not report the main planned
outcomes of a study, this fact should be stated and the reason indicated. State clearly if the
hypothesis being tested was formulated during or after data collection. Explain outcomes or
measurements unfamiliar to a general medical readership.
Results: The main outcomes of the study should be reported and quantified, including
baseline characteristics and final included/analyzed sample. Include absolute numbers and
measures of absolute risks (such as increase/decrease or absolute differences between groups),
along with confidence intervals (for example, 95%) or P values. Approaches such as number
needed to treat to achieve a unit of benefit may be included when appropriate. Measures of
relative risk also may be reported (eg, relative risk, hazard ratios) and should include
confidence intervals. Studies of screening and diagnostic tests should report sensitivity,
specificity, and likelihood ratio. If predictive value or accuracy is reported, prevalence or
pretest likelihood should be given as well. All randomized controlled trials should include the
results of intention-to-treat analysis, and all surveys should include response rates.
Conclusions and Relevance: Provide only conclusions of the study that are directly
supported by the results. Give equal emphasis to positive and negative findings of equal
scientific merit. Also, provide a statement of relevance indicating implications for clinical
practice or health policy, avoiding speculation and overgeneralization. The relevance
statement may also indicate whether additional study is required before the information
should be used in clinical settings.
Trial Registration: For clinical trials, the name of the trial registry, registration number, and
URL of the registry must be included.
Methods and Statistics
Describe statistical methods with enough detail to enable a knowledgeable reader with access
to the original data to reproduce the reported results. When possible, quantify findings and
present them with appropriate indicators of measurement error or uncertainty (such as
confidence intervals). Avoid relying solely on statistical hypothesis testing, such as the use of
P values, which fails to convey important quantitative information. Give details about
randomization. Describe the methods for and success of any blinding of observations. Report
complications of treatment. Give numbers of observations. Report losses to observation (such
as dropouts from a clinical trial). For multivariate models, report all variables included in
models, and report model diagnostics and proportion of variance explained by both individual
variables and the complete model.
Put a general description of methods in the “Methods” section. Restrict tables and figures to
those needed to explain the argument of the article and to assess its support. Use graphs as an
alternative to tables with many entries; do not duplicate data in graphs and tables. Avoid
nontechnical uses of technical terms in statistics, such as random (which implies a
randomizing device), normal, significant, correlations, and sample. Define statistical terms,
abbreviations, and most symbols. Provide a brief description of statistical tests used and levels
of significance to the Statistical Analysis paragraph in the Methods section.
Abbreviations
Do not use abbreviations in the title or abstract and limit their use in the text. Expand all
abbreviations at first mention in the text.
Units of Measure
Laboratory values are expressed using conventional units of measure, with relevant Système
International (SI) conversion factors expressed secondarily (in parentheses) only at first
mention. Articles that contain numerous conversion factors may list them together in a
paragraph at the end of the Methods section. In tables and figures, a conversion factor to SI
should be presented in the footnote or legend. The metric system is preferred for the
expression of length, area, mass, and volume. For more details, see the Units of Measure
conversion table on the website for the AMA Manual of Style.1
To read more about units of measure, click here.
Names of Drugs, Devices, and Other Products
Use nonproprietary names of drugs, devices, and other products, unless the specific trade
name of a drug is essential to the discussion.1(pp567-569)
Gene Names, Symbols, and Accession Numbers
Authors describing genes or related structures in a manuscript should include the names and
official symbols provided by the US National Center for Biotechnology Information (NCBI)
or the HUGO Gene Nomenclature Committee. Before submission of a research manuscript
reporting on large genomic data sets (eg, protein or DNA sequences), the data sets should be
deposited in a publicly available database, such as NCBI’s GenBank, and a complete
accession number (and version number if appropriate) must be provided in the Methods
section or Acknowledgment of the manuscript.
Reproduced Material
JAMA does not republish text, tables, figures, or other material from other publishers, except
under rare circumstances. Please delete any such material and replace with originals.
References
Authors are responsible for the accuracy and completeness of their references and for correct
text citation. Number references in the order they appear in the text; do not alphabetize. In
text, tables, and legends, identify references with superscript Arabic numerals. When listing
references, follow AMA style and abbreviate names of journals according to the journals list
in PubMed. List all authors and/or editors up to 6; if more than 6, list the first 3 followed by
“et al.” Note: Journal references should include the issue number in parentheses after the
volume number.
Examples of reference style:
1 Youngster I, Russell GH, Pindar C, Ziv-Baran T, Sauk J, Hohmann EL. Oral, capsulized,
frozen fecal microbiota transplantation for relapsing Clostridium difficile infection.
JAMA. 2014;312(17):1772-1778.
2 Murray CJL. Maximizing antiretroviral therapy in developing countries: the dual challenge
of efficiency and quality [published online December 1, 2014]. JAMA.
doi:10.1001/jama.2014.16376.
3 Centers for Medicare & Medicaid Services. CMS proposals to implement certain disclosure
provisions of the Affordable Care Act.
http://www.cms.gov/apps/media/press/factsheet.asp?Counter=4221. Accessed January
30, 2012.
4 McPhee SJ, Winker MA, Rabow MW, Pantilat SZ, Markowitz AJ, eds. Care at the Close of
Life: Evidence and Experience. New York, NY: McGraw Hill Medical; 2011.
For more examples of electronic references, click here.