067 seating modification, back posture

Seating modification, back posture and change in lower back pain

amongst occupational car drivers with chronic lower back pain

Dr Kelly-Ann Bowles

Prof Jenny Keating

Dr Lisa O’Brien

Mr Rob Laird

Dr Andrew Ronchi

Ms Sarah Tinitali

Prof Terry Haines

January 2016

Research report # 067-0116-R01

Further information

For further information on this report, please email [email protected]

mailto:[email protected]

i

This research report was prepared by

Dr Kelly-Ann Bowles and Prof Terry Haines,

Department of Physiotherapy, Monash University,

Allied Health Research Unit, Monash Health

Disclaimer

ISCRR is a joint initiative of WorkSafe Victoria, the Transport Accident Commission and Monash University. The

accuracy of the content of this publication is the responsibility of the authors. The opinions, findings, conclusions

and recommendations expressed in this publication are those of the authors and not necessarily those of TAC or

ISCRR.

This publication may not involve an exhaustive analysis of all existing evidence. Therefore it may not provide

comprehensive answers to the research question(s) is addresses. The information in this publication was current

at time of completion. It may not be current at time of publication due to emerging evidence.

Related documents (at the time of writing)

Title and author Reference number

N/A N/A

ii

Table of Contents

Executive Summary----------------------------------------------------------------------------------- 3

Purpose --------------------------------------------------------------------------------------------------- 4

Rationale -------------------------------------------------------------------------------------------------- 4

Key research questions ----------------------------------------------------------------------------- 5

Methods --------------------------------------------------------------------------------------------------- 5

Research/review Findings -------------------------------------------------------------------------- 7

Discussion, conclusions and implications --------------------------------------------------- 9

Potential impact, use of the research/review and recommendations ------------- 11

References --------------------------------------------------------------------------------------------- 11

Appendices -------------------------------------------------------------------------------------------- 13

Appendix A: Systematic Review Manuscript -------------------------------------------- 13

Appendix B: Methodology Manuscript ---------------------------------------------------- 32

3 ISCRR Research report 067-0116-R01

Executive Summary Background Low back pain has been described as the major cause of disability worldwide (1). In Australia, approximately 10% of the population experience substantial disability from low back pain in any six-month period (2). Low back pain also contributes to considerable economic strain. In the most recent Australian economic burden study, the estimated cost of low back pain in a one year period was AU$9.17 billion (2). AU$8.15 billion of this burden of disease was driven by loss of earnings and productivity costs, where people were not able to engage in their usual occupations (2). The notion that poor sitting posture is a risk factor for low back pain is reported widely in the literature (3-5). There is a substantial evidence base that has examined postures adopted in static sitting and relationships with low back pain (6-9). Comparatively less work however, has been undertaken on more dynamic sitting behaviour that may be required as part of occupational activities, such as driving an automobile. This project measured pelvic, trunk and lumbar flexion/extension and pelvic, trunk and lumbar lateral flexion through real time lumbar motion monitoring. Eleven occupational drivers with reported low back pain were recruited for the study and were monitored whilst driving their standard vehicle with the standard car seat and then a modified car seat (either replacement of the standard car seat with a modified car seat or the placement of a lumbar support roll in the standard car seat). Main findings

1. Our systematic review identified that a relationship between low back pain and postures assumed while driving may exist, but further research using more robust and reproducible measurement approaches needs to be undertaken to confirm this.

2. Our reliability study found that driving posture data is best represented by mean lumbar flexion, collected at any time within a work shift, but not within the first five minutes of any drive.

3. Our intervention study found that car seat modifications can lead to significant changes to pelvic flexion during driving. The effect that this change in posture then has on resultant pain requires further investigation.

Implications With a large number of Australian’s driving as a part of their occupation the mechanisms by which back pain may be reduced through car seat modification needs to be identified. Establishing interventions that may allow low back posture to be modified may reduce the risk of developing back pain for non-sufferers and may allow those with back pain to work more comfortably. This research has established that modifications to a standard car seat can significantly change pelvic flexion angles, with further research required to see the follow on effect to resultant pain. These modifications may be as simple as inserting an “off the shelf” lumbar support role for some sufferers. The beneficiaries of this work may include drivers of all workplace vehicles including taxi drivers, couriers and health clinicians visiting patients in their own home.


Purpose The purpose of this pilot research was to determine if modifications to a standard car seat can affect real-time lumbar spine posture in occupational drivers with reported back pain. Additionally this research will provide data for sample size estimates for a larger study, determine a reliable methodology for future research in the area and provide foundation information to assess the relationship between lumbar posture during driving and resultant low back pain.

Rationale Lower back pain is a leading cause of disease burden in Australia. Direct health care costs of lower back pain are in excess of $1 billion annually, though these are dwarfed by indirect costs (primarily time off work due to back pain) which are estimated to be eight times as large (2). Associations between driving automobiles for extended periods or driving as an occupation and development of lower back pain have been established since the 1970’s (10, 11). Despite this evidence, there is still uncertainty as to how prolonged driving causes lower back pain.

How might driving cause lower back pain?

Theories regarding whole body vibration, and extreme or sustained postures have been posited. Such physiological stressors could potentially contribute to lumber disc degeneration or straining of other soft-tissues in the lumbar spine. A recent review found that there is insufficient evidence to form a conclusion on whether whole-body vibration, postural stressors or other factors, specific or not specific to driving, are common causes of low back problems in drivers (11). Whole body vibration has also been argued to be a waning factor in absolute contribution to lower back pain due to engineering improvements and reductions in vibration in recent automobile models (12).

Some theories to explain how occupational driving can lead to lower back pain can be extrapolated from non-driving related sitting. A review of the mechanisms of lower back pain in sitting has found that sitting is unlikely to pose a threat to non-degenerate discs through the mechanism of raised intra-discal pressure (13). Thus greater focus is arguably warranted on understanding mechanisms that may strain other soft tissues in the lumbar spine, such as holding sustained postures at extremes of range of motion during driving. A survey of n=202 Australian airline pilots about seating found that inability to adjust the amount of lumbar and thigh area support were key concerns related to their seating options (14), which is consistent with the premise that sustained postures may contribute to discomfort and pain.

Can lumbar spine postures in sitting be modified?

Adults have difficulty moving into an “ideal” sitting posture with lumbar lordosis (extension) and thoracic kyphosis (flexion) (15), and are likely to require specialised seating to maintain such postures for extended periods. Modified seating has been shown to change lumbar spine position and the distribution of sitting pressures in laboratory conditions (16). However, it is unknown whether seating modifications in vehicles change lumbar spine postures when people are driving in real life.

Can modified seating reduce driving-related lower back pain?

At present, there are no randomised controlled trials of seating modifications interventions to reduce driving-related lower back pain and the burden it imposes on society. This study examined the extended, real-time lumbar spine posture of n=11 people with back pain who drive their vehicle for more than 2 hours per day as a part of their occupation. Three participants had their usual car seat replaced with a modified car seat, and eight participants placed a lumbar support in their car during a second day of driving. This will be the first study to provide real time, insitu measurement of lumbar spine posture while driving.


Key research questions Research objectives are to: i) investigate the association between sitting posture and low back pain while driving an automobile via a systematic review of the literature; ii) determine a reliable and repeatable methodology for assessing real time lumbar spine posture for occupational drivers; and iii) determine if modifications to a standard car seat result in a change in lumbar spine posture and resultant back pain for occupational drivers with reported back pain.

Methods Research question one was addressed via a systematic review that has been submitted for publication in “Applied Ergonomics”. The submitted manuscript can be found in Appendix A. Research question two was addressed by a methodology study that is in draft format for peer reviewed publication, with submission planned once the systematic review has been accepted for publication. This methodology manuscript can be found in Appendix B and will be submitted to “Spine”. For research question three the following methods were used to complete a prospective cohort study: Population: Occupational drivers who had reported back pain were recruited via IdealSeat Company, Mordialloc, Victoria, Australia and from community advertising. Sample size: As this was a pilot study a convenience sample was used based on available referrals from the car seat company, with eight community participants also recruited. Exclusion criteria: People who did not report low back pain or discomfort when driving their vehicle; those with insidious or serious pathologies of the lumbar spine, or conditions of the spinal cord; pregnant women; those who participate in large amounts of manual labour or heavy lifting as part of their job; and those who have an allergy to tape or glue. In addition, people who drove non-standard occupational vehicles during their work shift (e.g. bus, truck or train) were excluded due to the presence of confounding factors that have the potential to affect driving posture. Intervention: Driving posture when participants either had a modified seat placed in their vehicle, or placed a lumbar support roll into their standard car seat. Comparator: Driving position using a standard car seat. Outcomes: Lumbar spine posture during driving including lumbar, trunk and pelvis flexion/extension and lumbar, trunk and pelvis lateral flexion. Average pain at the end of the driving day (Visual analogue scale). Analysis: The analysis methodology from the second publication was followed in this study. Pelvic, trunk and lumbar flexion/extension and pelvic, trunk and lumbar lateral flexion were determined from the mean flexion data. Data from a drive was exported to Microsoft Excel, with time of entry into the vehicle was identified by a large increase and then decrease in lumbar flexion. The first five minutes and thirty seconds of the drive were ignored due to shown decreased repeatability for flexion data for this time period. The mean flexion data for each outcome over the subsequent five minutes of the drive were then calculated. Paired t-test analysis was completed using SPSS for all flexion and pain variables. Findings were deemed significant if p<0.05. Measurement of lumbar posture using the ViMove system (dorsiVi, Melbourne, Victoria, Australia): The ViMove system is a wireless inertial 3-D measurement system allowing real time measurement of spinal movement and electromyography of the erector spinae muscle group. Participants who had the modified car seat fitted into their vehicle were met at the IdealSeat company, and community participants were met at their place of work. All participants were fitted with the sensors by a trained biomechanist as displayed in Figure 1. Initial baseline live assessments were then completed on all participants to assess the individual’s lumbar posture and function. Participants were then given the Recording and Feedback Device (RFD) to carry during their day (needs to be within 10 metres of participant for monitoring). At the end of the day the system was returned to the researcher for analysis. Participants who placed the lumbar support roll into their vehicle, completed two days of


driving assessment in random order, with those who has the modified seat recording driving posture in both conditions on the same day. Figure 2 illustrates the printout of the monitoring session for one participant. Pelvic and trunk measures are each taken from their own motion sensor, with lumbar measures derived from both motion sensor measures.

A B Figure 1: A) Sensor placement for ViMove system with the large sensors measuring motion and the smaller sensors measuring electromyography and B) Recording and Feedback Device (RFD) carried by the participant during monitoring session (compared in size to mobile phone).


Figure 2: Monitoring session printout for one participant including driving sessions with the blue circles. Measurement of pain at the end of the driving day: A 0 to 10 visual analogue scale was used to assess participant pain at the end of the driving day (Figure 3). Participant who inserted the lumbar roll into their standard car seat reported pain data for both the intervention and control conditions.

Figure 3: Visual analogue scale question used at the end of the driving day.

Research/review Findings The systematic review found that a majority (six of the seven) of included papers reported a relationship between driving posture and low back pain, but that these findings are based on studies with considerable methodological flaws that cannot be reproduced. This field of research is clearly still in its infancy given the low number of studies conducted (7 papers were derived from 5 studies) and questionable methods used to collect data, particularly related to posture. A relationship between low back pain and postures assumed while driving may exist, but further research using more robust and reproducible measurement approaches needs to be undertaken to confirm this. The review also suggested that future research is required to enhance our understanding of whether postures assumed while driving contribute to low back pain. Importantly, as tools are now available that are capable of measuring outcomes such as sitting posture in real time during activities such as driving (17, 18), further research assessing lumbar flexion measures during driving are required. This second paper for this project provides a methodology for the classification and analysis of real-time lumbar flexion data during driving. Based on the results, it is recommended that driving posture data be represented by mean lumbar flexion, collected at any time within a work shift, but not within the first five minutes of any drive. Peak lumbar flexion showed weaker test-retest reliability in comparison to mean lumbar flexion, but did demonstrate at least acceptable levels of test-retest reliability. Measuring the standard deviation of lumbar flexion showed poor test-retest reliability and the use of this outcome cannot be recommended at this time. For the prospective cohort study, 11 participants completed a driving session in a standard car seat and with a fitted modified car seat or the use of a lumbar support roll. Three participants were male and eight were female, with participants working in occupations such as sales representative, public servants and health professionals who visited patients at home. The mean age of the participants was 39.5 years with a range from 24 to 53 years. The mean time of back pain onset was roughly 8 years and participants reported an mean pain intensity score of 42 (0 -100 scale using QVAS; (19)) at baseline. The addition of the lumbar support roll to the participants car seat resulted in a significant increase in pelvic extension (p=0.037) by approximately six degrees. Figure 4 illustrates the mean pelvic flexion angle for each participant during driving in both seating conditions. Although no other measure resulted in a significant change, the trunk sensor for one participant did cease collecting data during the trial, resulting in no trunk and an incorrectly derived lumbar measure for that condition (excluded from analysis). This did result in a sample size of seven participants for the lumbar and trunk outcomes. Therefore although lumbar flexion was reduced by a similar amount to the pelvic flexion measures, this finding was not significantly (p=0.170) possibly due to the smaller sample size and the slightly greater variance within the data. No significant change was seen in the lateral flexion measures as a result on modifying the car seat.


Figure 4: Mean pelvic flexion for all participants with the lumbar support roll, in both seating conditions. The insertion of the lumbar roll resulted in a non-significant (p=0.351) decrease of one visual analogue scale point in average pain when compared to the standard car seat. Figure 5 illustrates the average reported pain for each participant in each car seat condition. One participant did comment a priori that an increase in lumbar extension was know to increase her pain. All but this participant reported a preference to the lumbar support roll condition post driving. This participant is represented by the orange line in Figures 4 and 5 and recorded the greatest change in pelvic flexion/extension, and the largest increase in pain with the additional of the lumbar roll. As the researchers identified that back pain is not uniform in it’s triggers and this participant could been deemed as an outlier for this cohort, pain data was then analysed without this participant. From this analysis, the reduction in pain was not significant (p=0.078) but did suggest a trend toward the positive effect of the insertion of the lumbar roll on back pain. It should be noted that the position of the pelvic sensor could possibly affect pain measures in the lumbar support roll condition, with three participants noting the sensor did “dig in more” with the lumbar support roll in place.

-50

-45

-40

-35

-30

-25

-20

-15

-10

-5

0

Normal LumbarRoll

FLEX

ION

AN

GLE

(O

)

Mean pelvic flexion for different conditions


Figure 5: Average pain for all participants with the lumbar support roll, in both seating conditions. As the participant sample available for the modified car seat group was limited, no significant results were found between the seat conditions for this group. Two participants had near identical mean pelvic measures for both conditions, with the non-significant (p=0.192) increase in pelvic extension for this group approximately four degrees. As both conditions were completed on the one driving day, pain data for this cohort was not available for each driving condition. This research does demonstrate that car seat modifications can lead to significant changes to pelvic flexion during driving. The effect that this change in posture then has on resultant pain requires further investigation.

Discussion, conclusions and implications To our knowledge this is the first study to provide real time, insitu measurement of lumbar spine posture while driving. This research has established that although a relationship between low back pain and postures assumed while driving may yet exist, but further research using more robust and reproducible measurement approaches need to be undertaken to confirm this finding. A methodology study did find that real time measurement of lumbar posture represented by mean flexion angles, is highly repeatable and reliable, and using these methods, this research did shown that modifications to a standard car seat with the insertion of a lumbar support roll, can significant modify pelvic flexion during driving. Prior to this research the effect of an intervention on sustained flexed postures and low back pain for occupational drivers was unknown (Figure 6A). Although some research had discussed the effect of posture on back pain while driving (20-22), these papers did not measure exact lumbar angles and investigated changes in posture whilst driving, rather than assessing sustained flexion angles. This pilot study has provided foundation research outcomes in understanding the effect of seating modifications on mean pelvic lumbar flexion during driving. We have established that modification to a car seat can lead to significant changes in pelvic flexion (Figure 6B). In addition, there is a current trend

0

1

2

3

4

5

6

7

8

9

10

LumbarRoll Normal

PA

IN (

VA

S)

Average pain for different conditions


suggesting that the modification to the car seat could reduce low back pain. Future research is now required to further establish the effect of car seat modification on low back pain and to further investigate the link between changes in mean pelvic flexion and low back pain.

A

B Figure 6: Flow chart diagram illustrating the knowledge regardin the relationship between car seat modification and low back posture and resultant pain prior to (A) and post (B) this research project. The limitations of this study were:

The small sample size of this pilot research may have affected the statistical finding and therefore further research with a larger sample is require to confirm these preliminary results;

Average low back pain measures were not collected for each seat condition for the modified car seat group, therefore the effect of the modified car seat on low back pain can not be reported;

The ViMove system includes a low back pelvic sensor that was reported did “dig in more” to the participant’s back when the lumbar support roll was in place. This may have affected the average low back pain measures for this condition.


Potential impact, use of the research/review and recommendations With a large number of Australian’s driving as a part of their occupation the mechanisms by which back pain may be reduced through car seat modification needs to be identified. Establishing interventions that may allow low back posture to be modified may reduce the risk of developing back pain for non-sufferers and may allow those with back pain to work more comfortably. This research has established that modifications to a standard car seat can significantly change pelvic flexion angles, with further research required to confidently establish the follow on effect to resultant pain. The modification to the car seat may be as simple as inserting an “off the shelf” lumbar support roll, however different back issues may require different interventions to relieve back pain while driving. The beneficiaries of this work may include drivers of all workplace vehicles including taxi drivers, couriers and health clinicians visiting patients in their own home.

References

1. Hoy D, March L, Brooks P, Blyth F, Woolf A, Bain C, et al. The global burden of low back pain: estimates from the global burden of disease 2010 study. Annuls of the Rheumatic Diseases [Internet]. 2014; 73(6):[968-74 pp.]. 2. Walker BF, Muller R, Grant WD. Low back pain in Australian adults: the economic burden. Asia Pac J Public Health. 2003;15(2):79-87. 3. Manek NJ, MacGregor AJ. Epidemiology of back disorders: prevalence, risk factors, and prognosis. Curr Opin Rheumatol. 2005;17(2):134-40. 4. Neumann WP, Wells RP, Norman RW, Kerr MS, Frank J, Shannon HS. Trunk posture: reliability, accuracy, and risk estimates for low back pain from a video based assessment method. Int J Ind Ergonom. 2001;28(6):355-65. 5. Yilmaz E, Dedeli O. Effect of physical and psychosocial factors on occupational low back pain. Health Science Journal. 2012;6(4):598-609. 6. Claus AP, Hides JA, Moseley GL, Hodges PW. Is 'ideal' sitting posture real?: Measurement of spinal curves in four sitting postures. Manual Therapy. 2009;14(4):404-8. 7. Williams MM, Hawley JA, McKenzie RA, van Wijmen PM. A comparison of the effects of two sitting postures on back and referred pain. Spine. 1991;16(10):1185-91. 8. Dankaerts W, O'Sullivan P, Burnett A, Straker L. Differences in sitting postures are associated with nonspecific chronic low back pain disorders when patients are subclassified. Spine [Internet]. 2006; 31(6):[698-704 pp.]. 9. Park RJ, Tsao H, Claus AP, Cresswell AG, Hodges PW. Recruitment of Discrete Regions of the Psoas Major and Quadratus Lumborum Muscles Is Changed in Specific Sitting Postures in Individuals With Recurrent Low Back Pain. Journal of Orthopaedic and Sports Physical Therapy. 2013;43(11):833-40. 10. Kelsey JL, Githens PB, O'Conner T, Weil U, Calogero JA, Holford TR, et al. Acute prolapsed lumbar intervertebral disc. An epidemiologic study with special reference to driving automobiles and cigarette smoking. Spine. 1984;9(6):608. 11. Gallais L, Griffin MJ. Low back pain in car drivers: A review of studies published 1975 to 2005. Journal of sound and vibration. 2006;298(3):499-513. 12. Lings S, Leboeuf-Yde C. Whole-body vibration and low back pain: A systematic, critical review of the epidemiological literature 1992–1999. International archives of occupational and environmental health. 2000;73(5):290-7. 13. Claus A, Hides J, Moseley GL, Hodges P. Sitting versus standing: Does the intradiscal pressure cause disc degeneration or low back pain? Journal of Electromyography and Kinesiology. 2008;18(4):550-8. 14. Lusted M, Healey S, Mandryk J. Evaluation of the seating of Qantas flight deck crew. Applied Ergonomics. 1994;25(5):275-82. 15. Claus AP, Hides JA, Moseley GL, Hodges PW. Is ‘ideal’sitting posture real?: Measurement of spinal curves in four sitting postures. Manual Therapy. 2009;14(4):404-8. 16. Makhsous M, Lin F, Hendrix RW, Hepler M, Zhang LQ. Sitting with adjustable ischial and back supports: biomechanical changes. Spine. 2003;28(11):1113.


17. Charry E, Umer M, Taylor S. Design and validation of an ambulatory inertial system for 3-D measurements of low back movements. The Meeting of Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP); 2011 Dec. 6-9; Adelaide, South Australia2011. p. 58-63. 18. Ronchi AJ, Lech M, Taylor NF, Cosic I. Reliability study of the new back strain monitor based on clinical trials. the meeting of the 30th Annual Institute of Electrical and Electronics Engineers International Engineering in Medicine & Biology Society (IEEE EMBS) Conference; Vancouver, British Columbia, Canada2008. 19. Von Korff M, Deyo RA, Cherkin D, Barlow W. Back pain in primary care: outcomes at 1 year. Spine. 1993;18(7):855-62. 20. Tamrin SBM, Yokoyama K, Jalaludin J, Aziz NA, Jemoin N, Nordin R, et al. The association between risk factors and low back pain among commercial vehicle drivers in peninsular Malaysia: a preliminary result. Industrial health. 2007;45(2):268-78. 21. Okunribido OO, Magnusson M, Pope MH. Low back pain in drivers: The relative role of whole-body vibration, posture and manual materials handling. Journal of Sound and Vibration. 2006;298(3):540-55. 22. Sakakibara T, Kasai Y, Uchida A. Effects of driving on low back pain. Occupational medicine. 2006;56(7):494-6.


Appendices

Appendix A: Systematic Review Manuscript

Poor posture causes low back pain

while driving; evidence-based position

or dogma?

A systematic review of the association between sitting posture

and low back pain while driving an automobile

Sarah Tinitalia, Jennifer L Keatinga, Kelly-Ann Bowles a,b, Terry Haines a,b

aMonash University Peninsula Campus, McMahons Road, Frankston, Victoria, Australia

3199

b Allied Health Research Unit, Kingston Centre, 400 Warrigal Road, Cheltenham,

Victoria, Australia 3192

[email protected]

[email protected]

[email protected]

[email protected]

Corresponding Author:

Kelly-Ann Bowles

Allied Health Research Unit, Kingston Centre, 400 Warrigal Road, Cheltenham,



[email protected]

Ph: +61 425 261 585

This paper can be in black and white print

Abstract

Several authors have claimed a relationship between poor posture and low back pain

while driving. The strength of these claims however, is yet to have been subjected to

critical analysis and review. We undertook a systematic review and critical appraisal

of the evidence examining this relationship. Six of the seven articles identified an

association between these variables, yet none of these studies used a validated and

reliable means for measuring driving posture. Only one study used a measure of back

pain that has previously been subjected to validation, though this tool was translated

into a different language without report of the translation procedure. These and other

limitations bring the strength of the relationship between posture and low back pain

while driving into question. Future research in this field needs to employ validated and

reliable methods for measuring posture (preferably in real-time) and pain to advance

our understanding of this relationship.

Keywords

Low back pain

Driving

Posture


Introduction

Low back pain has been described as the major cause of disability worldwide (1). In

Australia, approximately 10% of the population experience substantial disability from

low back pain in any six-month period (2). Low back pain also contributes to

considerable economic strain. In the most recent Australian economic burden study,

the estimated cost of low back pain in a one year period was AU$9.17 billion (2).

AU$8.15 billion of this burden of disease was driven by loss of earnings and productivity

costs, where people were not able to engage in their usual occupations (2).

There are many occupations that require extended periods of sitting. The notion that

poor sitting posture is a risk factor for low back pain is reported widely in the literature

(3-5). The ability to engage in these occupations may therefore be impaired by low

back pain attributable to poor sitting postures. There is a substantial evidence base

that has examined postures adopted in static sitting and relationships with low back

pain (6-9). Comparatively less work however, has been undertaken on more dynamic

sitting behaviour that may be required as part of occupational activities, such as

driving an automobile.

The link between poor sitting posture and low back pain during driving may have been

first postulated by Troup (10), though they provided no direct evidence of this link. A

later review by Lyons (11) discussed a potential mechanism; that low back pain may

be caused by adoption of awkward driving postures due to the poor ergonomic

design of vehicles. However, Lyons (11) referenced data from only one empirical study

by Krause et al. (12) who reported an increased risk of back or neck pain for drivers

who experienced ‘ergonomic problems’, such as difficulty seeing out of the vehicle or

problems with operating vehicle controls. Krause et al. (12) did not directly measure

driving posture beyond self-report, and their findings should therefore be treated with

caution.


More recently, a review by Lis et al. (13) considered the association between

occupational sitting and low back pain while assuming awkward postures and/or

while exposed to whole-body vibration. The review considered a range of driving

populations, including drivers of buses, tractors, cranes, helicopters, and rubbish

collection trucks. Four eligible papers reported a moderate positive association

between low back pain and sitting in a vehicle (average OR=2.1). The conditions

experienced by the drivers in this review are likely to differ considerably across

participant occupations, particularly in regards to the movements of the spine and

upper limbs when operating various vehicle functions. The trunk and upper limb

movements required of a helicopter pilot or garbage truck driver are likely to differ to

those required of a bus or truck driver. Trunk movements in automobile drivers are also

likely to differ when an individual is driving on an uneven surface, or at a high speed,

in comparison to a standard public road. It is therefore difficult to make individual

findings regarding pain experienced while operating specific vehicles based on a

review of such a heterogenous group of vehicles.

Given the limitations of these previous reviews, and the publication of more recent

empirical studies, a systematic review was undertaken to synthesise and critically

appraise the available evidence in this field. An understanding of this relationship is

needed to guide the appropriate development of future strategies to minimise the

burden of low back pain associated with driving.

Review Aim

The aim of this review was to synthesise and appraise the evidence examining the

association between sitting posture during occupational driving and low back pain,

and to identify factors that may mediate such an association.

Material and Methods

Searching

Searching was performed by the lead author. The complete holdings of five databases

(AMED, CINAHL Plus, Cochrane Central Register of Controlled Trials, Cochrane


Database of Systematic Reviews, and Ovid MEDLINE) were searched up to February

2015. Search results were pooled in bibliographic management software, duplicates

were removed, and ineligible papers were deleted based on title, abstract, and full

text. Reference lists of relevant reports were then screened for additional papers not

found in the primary search. Author and citation checks were performed for all first

authors of eligible papers. Figure 1 presents the search terms, truncations and Boolean

operators used. A sample search is available from the first author on request.

Figure 1: Search Terms

1. Sit$ OR Seat$ OR Driv$

2. Posture$ OR Position$ OR Angle$ OR Pose$

3. Low$ back OR Low-back OR Low$ spin$ OR Low-spin$ OR Low$ vertebra$ OR

Low-vertebra$ OR Lower-back OR Lower-spin$ OR Lower-vertebra$ OR Lumbar

OR Lumbar-back OR Lumbar-spin$ OR Lumbar-vertebra$ OR Lx

4. Automobile$ OR Vehicle$ OR Car$ OR Taxi$ OR Bus$ OR Van$ OR Truck$ OR

Lorr$ OR Transport$

5. 1 AND 2 AND 3 AND 4

Eligibility criteria

Papers were included in the review if they reported data on the relationship between

sitting posture while driving a car, bus, truck or van and pain in the lumbar spine region;

measured driving posture and low back pain; and were reported in English. To minimise

confounding factors, papers were excluded if they included people with spine

anomalies; genetic conditions associated with the spine; insidious or serious

pathologies of the lumbar spine (e.g. cancer, inflammatory diseases, fracture);

conditions or injuries involving the spinal cord; or pregnant women. Studies that

considered sitting posture in a rally car or other forms of occupational automobiles

were also excluded, due to factors associated with each vehicle type: differing driving

surfaces in comparison to a standard public road (e.g. tractors); differing forces acting

through the body of the driver (e.g. rally cars, due to their extreme speed); and the

differing requirements of the tasks being performed by the driver (e.g. forklifts,

helicopters).

Planned Quality Assessment


A modified Reliability Quality Assessment Tool by Pretorius and Keating (14) was

adapted to assess the presence of bias in included studies. Each report was assessed

against the criteria of inception cohort, method of assessment, subject blinding,

assessor blinding and analysis methods. Modifications made to the tool included the

addition of the subject blinding criteria, separation of the inception cohort criteria into

two items (random sampling, and comparison of sample and source populations), and

removal of the attrition criteria and items specific to the study by Pretorius and Keating

(14). The modified tool can be viewed in Table 1. A critical analysis was also planned

to further consider sources of bias, including methods by which low back pain and

driving posture were measured, and methods by which these measurements were

analysed.

Table 1: Modified Reliability Quality Assessment Tool

Criteria Yes =

1

No =

0

1. Inception cohort

All those eligible for admission into the study were invited to participate.

Scoring: Yes, if the report states that consecutive, or randomly selected,

eligible participants were invited to participate in the study.

2. Inception cohort

All participants in the study were a representation of the source

population.

Scoring: Yes or no. Yes if the report describes the participants and they are

a representative of the group of interest e.g. the participants involved in a

study of bus drivers represent the bus driver population.

3. Method of assessment

The methods used to measure driving posture and low back pain were

described in enough detail to enable replication.

Scoring: Yes or no. Yes if the method is explained to a degree that

replication is possible.

4. Subject blinding

During the observation or measurement of posture, participants were

unaware of the outcome being assessed.

Scoring: Yes or no. Yes, if participants were not aware that the relationship

between sitting posture and pain was being assessed.


5. Blind Assessor

Drivers’ posture, and their pain, were assessed by independent assessors or

if not, it was probable that one measurement did not bias the

measurement of the other.

Scoring: Yes or no. Yes if the paper states that there was blinding of the

assessor or a method of posture and pain measurement was used that

minimised the possibility of bias.

6. Analysis

Data were reported that enabled a view of the relationship between pain

and driving posture.

Scoring: Yes or no. Non exhaustive examples of such data could be raw

scores for each participant on both measures, correlations between pain

and posture measures, mean scores (and variability estimates) on one

parameter for subjects grouped on the other parameter (e.g. posture in

high versus low pain subjects), change in pain with changes in posture.

TOTAL SCORE

Planned Data Extraction and Synthesis

Data extracted from eligible papers included study design, participant characteristics,

methods used to assess driving posture and low back pain, data analysis methods,

and the reported statistical or textual description of the association between driving

posture and low back pain. Any evidence provided as to the validity or reliability of

assessment and analysis methods was also extracted. Where data collection

techniques and reporting methods were sufficiently comparable, a meta-analysis was

planned. In the event this was not possible, a narrative, critical synthesis approach was

planned.

Results

Search yield and search results

A total of 485 articles were identified by the search strategy. There were 41 duplicates,

which were then deleted. A further 387 articles were excluded based on title and

abstract, and the remaining 57 articles were read in full. 50 articles were excluded

following full text review, with the remaining seven publications included (15-21). Figure


2 presents a PRISMA flow chart describing the search and screening results as per

Moher et al. (22).

461 articles identified through searching

(AMED = 30, CINAHL Plus = 3, Cochrane

Central Register of Controlled

Trials = 36, Cochrane Database of

Systematic Reviews = 108, Ovid MEDLINE

= 284)

24 additional articles identified through other

sources

444 articles after duplicates

removed

Total search yield: 485

444 articles screened 387 articles excluded

(333 by title, 54 by abstract)

57 full-text articles assessed for

eligibility

50 full-text articles excluded:

17 did not measure driving

posture in an eligible vehicle

21 did not measure driving

posture or low back pain

7 did not report data on how

driving posture affects LBP

7 articles eligible for

qualitative synthesis and

quantitative synthesis

Figure 2: Flow of studies into the review


Quality Assessment

Quality assessment using the modified Reliability Quality Assessment Tool revealed that

all except one study (19) failed to provide sufficient detail in the method to allow for

replication of the low back pain and/or driving posture assessment approach. None

of the studies reported any degree of blinding of the participant or researcher of what

posture assessment results were when capturing pain data or vice versa. This may be

important as a patient or researcher could potentially (consciously or unconsciously)

influence the response to a later question based on the response to the former.

Characteristics of included studies

The populations in the eligible studies were occupational drivers, including bus drivers,

taxi drivers, police officers, and drivers of trucks and vans. Two of the papers by

Okunribido et al. (16, 17) presented data for the same study population. A further

paper published by the same lead author is likely to include bus drivers from the same

sample, as population characteristics were identical. These papers were handled as

three separate studies, as they reported different relationships between driving posture

and low back pain. Four of the included papers utilised a cross-sectional survey design

(15-17, 19), and three papers used both a cross-sectional survey and an observational

component (18, 20, 21).

The average mean participant age across the included studies was 42.4 years. Sample

sizes varied, ranging from 61 (18) to 1242 (15). Participants were predominantly male

due to the eligibility criteria of individual studies (21), or the presence of few females in

the source population (15-19). Table 2 presents sample characteristics and design of

included studies.


Table 2: Study Design and Population Characteristics Head

Author

(Year)

Study Design Driver

Type

Sample

size at

start of

study

Sample

size at

end of

study

Mean (SD)

Age (years)

Gender

Ratio

(M:F)

Mean (SD)

BMI (kg/m2)

Mean (SD)

driving

distance per

day (km)

Mean (SD)

driving time

per day

(hours)

Mean (SD)

days of

driving

each

month

Mean (SD)

length of time in

current

profession

(years)

Bovenzi (2006)

Cross-sectional survey/ Observational

Bus - 171 43.6 (6.6) 1:0 26.6 (3.2) - 6.0 (0.8) - 16.1 (8.5)

Chen (2005)

Cross-sectional survey

Taxi 1355 1242 44.5 (8.7) 1193:49 - - 9.8 (2.8) 26.2 (2.6) 11.4 (7.8)

Okunribido (2006)


Police

Truck/ Van

Bus

Taxi

Police: 75

Truck/ Van: 110

Bus: 80

Taxi: 90

Police: 58

Truck/ Van: 64

Bus: 61

Taxi: 30

Police: 34.5 (5.9)

Truck/Van: 46.9 (11.0)

Bus: 47.6 (10.4)

Taxi: 49.3 (8.3)

Few women, data pooled

Police: 26.0 (2.7)

Truck/Van: 27.7 (4.5)

Bus: 28.3 (4.4)

Taxi: 28.3 (4.8)

- - - Police: 12.9 (7.24)

Truck/van: 10.5 (8.6)

Bus: 16.1 (11.7)

Taxi: 11.1 (8.7)

Okunribido (2007)


Bus 80 61 LBP: 48.1 (9.7)

No LBP: 46.8 (11.5)

19:1 LBP: 28.5 (4.0)

No LBP: 28.1 (4.9)

- LBP: 7.5 (1.4)

No LBP: 7.6 (1.8)

- LBP: 14.3 (7.8)

No LBP: 17.9 (12.2)

Okunribido (2008)


Police

Truck/ Van

Bus

Taxi

Police: 75

Truck/Van: 110

Bus: 80

Taxi: 90

Police: 58

Truck/ Van: 64

Bus: 61

Taxi: 30

Police: 34.5 (5.9)

Truck/Van: 46.9 (11.0)

Bus: 47.6 (10.4)

Taxi: 49.3 (8.3)

Few women, data pooled

Police: 26.0 (2.7)

Truck/Van: 27.7 (4.5)

Bus: 28.3 (4.4)

Taxi: 28.3 (4.8)

- - - Police: 12.9 (7.2)

Truck/van: 10.5 (8.6)

Bus: 16.1 (11.7)

Taxi: 11.1 (8.7)

Sakakibara (2006)


Car - 551 LBP: 37 (8.5)

No LBP: 35.8 (8.7)

530:21 - LBP: 111 (54)

No LBP: 115 (104)

LBP: 3.8 (1.8)

No LBP: 3.5 (1.8)

- LBP: 14.2 (8.8)

No LBP: 12.8 (8.7)

Tamrin (2007)


Bus - 760 43 (8.64) - - - 10.5 (0.1) - -


Posture Measurement

Tamrin and colleagues (20) measured posture through direct observation by filming

participants with a video camera while driving. This video footage was then rated by

an unspecified number of raters to count the number of times that various movements

(bending forward, leaning, sitting straight, twisting) were performed. The participants

in the study by Okunribido et al. (18) were observed by an unspecified assessor while

driving. The assessor noted the posture configuration (“torso against backrest, torso

straight, torso bent, torso twisted, and/or torso bent and twisted simultaneously”)

assumed by the driver at one-minute intervals (p. 30). The inter-rater reliability of these

observation approaches were not specified. There was no measurement of the

magnitude of movement in each direction nor the length of time spent in each

movement. Bovenzi et al. (21) performed direct observation by taking video and still

photography footage of participants during a workshift, but did not provide detail on

the methods with which these data were interpreted. Bovenzi et al. (21) and

Okunribido et al. (18) also assessed driving posture with a self-assessed questionnaire,

in addition to direct observation.

The self-assessed questionnaire method of posture measurement was utilised by six

papers (15-19, 21). One paper asked participants to select a posture that they usually

adopted while driving from a polychotomous list (straight, slightly slouched, or

slouched) (19). Participants were unable to specify a combination of these postures

or relative time spent in each posture, indicating an underlying assumption that drivers

adopt only one posture. Five of the questionnaires asked participants to rate the

frequency with which specific driving postures were adopted (15-18, 21). None of

these papers reported data demonstrating the reliability or validity of their

measurement approach. Okunribido et al. (16-18) reported the use of a previously

validated questionnaire developed by Pope et al. (23), however the reference

provided was only for a draft questionnaire that has not since undergone further

investigation of its psychometric properties. Only one study reported the wording of

the question that was used to elicit posture assessment data (19). The issues of

reproducibility, reliability and validity for self-reported measures of posture can be

questioned as Okunribido et al. (18) found discrepancies between self-report and


direct observation approaches. They found participants reported that ‘torso against

backrest’ was assumed more commonly than ‘torso straight’, but that observation

found the reverse to be true.

Low Back Pain Measurement

All seven papers measured low back pain using a self-assessed questionnaire.

Sakakibara et al. (19) developed a questionnaire, while the other authors used or

modified previously formed questionnaires (15-18, 20, 21). The surveillance

questionnaire used to measure driving posture by Okunribido et al. (16-18) was also

used to measure low back pain (see Section 3.3.2). Bovenzi et al. (21) reported the use

of a modified Nordic Questionnaire yet referenced the standardised version, and did

not provide information on the specific modifications made. Chen et al. (15) based a

questionnaire on items from the Nordic Questionnaire and the Job Contents

Questionnaire in combination with other items, but did not report the final item set.

Tamrin et al. (20) used the Standardised Nordic Questionnaire translated into Malay

language, however, it is unclear if the best practice crosscheck, as specified by

Kuorinka et al. (24) was performed following translation. Sakakibara et al. (19)

developed a questionnaire with items that measured the presence, severity, duration

and previous history of low back pain, and the effect of driving on low back pain.

Unlike the other six articles, Sakakibara et al. reported the questionnaire items (19).

The validity of low back pain measurement approaches employed by the included

studies is unknown. This is due to modifications made to previously formed

questionnaires, the use of questionnaires lacking validation information, and the

formation of new questionnaires. Reliability information was also not provided for the

measurement approaches within these articles.

The association of driving posture and low back pain

Five of the seven papers reported an association between low back pain and driving

with the back in a bent or twisted posture (15-17, 20, 21). This posture was associated


with current low back pain (16) and history of low back pain in the past 12 months (15,

17, 20, 21). Driving with the back bent and twisted simultaneously was also associated

with history of low back pain in the past 12 months (17).

Okunribido et al. also reported an association between driving with the torso against

the backrest and both current low back pain (16) and history of low back pain in the

past 12 months (17). Tamrin et al. (20) reported an association between ‘torso straight’

and a lower risk of low back pain. In contrast to the findings of these six papers,

Sakakibara et al. (19) found no significant difference between the driving postures of

participants with or without low back pain (p=0.67).

Studies by Bovenzi et al. (21) and Okunribido et al. (16-18) also examined the

relationship between a summative score incorporating posture (+/- other factors) and

low back pain. Bovenzi et al. (21) calculated a self-developed ‘physical load index’

for each participant based on their exposure to ‘awkward postures’ and ‘heavy

physical work’. Observational and questionnaire data were used to determine

exposures. Awkward posture exposure was calculated through consideration of each

posture and how long participants assumed each posture during a shift (never, less

than 1-hour, 1-2-hours). Exposure to heavy physical work was determined by rating the

frequency with which physical activities were performed (not at all, 1-10 times, more

than 10 times). The average physical workload index for the sample was then divided

into quartiles to represent grades of physical load (mild, moderate, hard and very

hard). A very hard physical load index was associated with an increased risk of low

back pain disability (OR 2.57, 95% CI 1.25-5.26) and history of low back pain within the

previous 12 months (OR 2.25, 95% CI 1.39-3.64) (21). However, the physical workload

index incorporated both driving and non-driving work postures, as well as non-driving

activities. The relationship between the physical workload index and low back pain is

therefore not a representation of the relationship between driving posture and low

back pain.

Okunribido et al. (16-18) calculated a ‘personal posture score’ for each participant by

assigning severity points to specific postures and frequencies of occurrence. Driving


with the torso against the backrest was deemed the least severe posture, with the

greatest severity assigned to driving with the back bent and twisted simultaneously.

The severity point of a posture assumed by an individual was multiplied by the

frequency of occurrence point. The addition of all point totals determined a posture

score for the individual (16-18). Drivers of police cars and taxi drivers had low posture

scores, while truck, van and bus drivers had medium posture scores. Medium posture

scores were associated with current low back pain (OR 1.288, 95% CI 0.598–2.777) (16).

In the 2007 paper by Okunribido et al., however, drivers with low back pain were

associated with a lower posture score compared to the drivers with no pain.

Okunribido et al. (16) reported that the posture score was yet to be validated.

Discussion

This review has found that a majority (six of the seven) of included papers reported a

relationship between driving posture and low back pain, but that these findings are

based on studies with considerable methodological flaws that cannot be reproduced.

This field of research is clearly still in its infancy given the low number of studies

conducted (7 papers were derived from 5 studies) and questionable methods used to

collect data, particularly related to posture. A relationship between low back pain and

postures assumed while driving may yet exist, but further research using more robust

and reproducible measurement approaches needs to be undertaken to confirm this.

Our conclusion of uncertainty of the presence of a relationship contrasts to that of the

review by Lis et al (13). Lis et al. (13) concluded that there was an association between

the low back pain and awkward driving postures, such as ‘sitting forward’, or driving

with the trunk “flexed, bent and twisted” (p. 289). However, their conclusion was driven

by four studies (25-28) that were excluded from our review as they were not amongst

standard road vehicles. Further, Lis et al (13) did not undertake any critical appraisal

of the measurement approaches used to capture posture or pain data, and did not

use such an appraisal to influence their conclusions as we have done.


A criticism raised earlier regarding previous reviews in terms of heterogeneity of the

included participant populations, could also be raised of this review. We excluded

studies amongst helicopter pilots, cranes, and other vehicles that are not

conventionally used for road-based transportation. This means that we did include

studies amongst drivers of cars, vans, buses, and trucks. It is possible that the nature of

relationship between low back pain and posture between these vehicle types may be

different. However, subdividing to this extent would have resulted in a very limited

number of papers being included. Furthermore, these studies did not report findings in

a consistent manner sufficient to allow statistical pooling.

This review led to identification of four studies (29-32) that included potentially relevant

data from mixed populations (including those that would have been included and

excluded from our review) but did not present this data in a disaggregated way. These

studies were excluded from our review. We may have had sufficient data of higher

quality to make a conclusion in favour of a relationship between low back pain and

posture while driving, had the disaggregated data been available.

Future research is required to enhance our understanding of whether postures

assumed while driving contribute to low back pain. Importantly, tools are available

that are capable of measuring an outcome such as sitting posture in real time that

could be used for this purpose (33, 34). These tools have been investigated for validity

and reliability (34), and have already started to be used for clinical applications (35).

In addition, cross-sectional studies used to date provide no temporal sequencing that

may help satisfy this Bradford Hill criteria of causality (36). For this, prospective studies

that demonstrate first, the adoption of particular postures, followed by the

development of low back pain are required. These studies would provide strong

justification for intervention studies that could be used to demonstrate whether

changing postures assumed while driving can be useful for reducing the burden of low

back pain.

Conclusions


The aim of this review was to synthesise and appraise the evidence examining the

association between sitting posture during occupational driving and low back pain,

and to identify factors that may mediate such an association. The relationship

between these outcomes remains open to challenge, due the use of measurement

methods that lacked validity and reliability. A true understanding of this relationship

cannot be known until further studies using validated, reliable and real-time methods

for posture measurement are performed.

Acknowledgements

This systematic review was completed as part of an Honours degree, without a funding

source. The review is an advisory paper for a study funded by the Institute for Safety,

Compensation and Recovery Research (ISCRR). Although this paper was written

independently from the study, the authors would like to acknowledge the support

provided by ISCRR.


References

1. Hoy D, March L, Brooks P, Blyth F, Woolf A, Bain C, et al. The global burden of low back pain: estimates from the global burden of disease 2010 study. Annuls of the Rheumatic Diseases [Internet]. 2014; 73(6):[968-74 pp.]. 2. Walker BF, Muller R, Grant WD. Low back pain in Australian adults: the economic burden. Asia Pac J Public Health. 2003;15(2):79-87. 3. Manek NJ, MacGregor AJ. Epidemiology of back disorders: prevalence, risk factors, and prognosis. Curr Opin Rheumatol. 2005;17(2):134-40. 4. Neumann WP, Wells RP, Norman RW, Kerr MS, Frank J, Shannon HS. Trunk posture: reliability, accuracy, and risk estimates for low back pain from a video based assessment method. Int J Ind Ergonom. 2001;28(6):355-65. 5. Yilmaz E, Dedeli O. Effect of physical and psychosocial factors on occupational low back pain. Health Science Journal. 2012;6(4):598-609. 6. Claus AP, Hides JA, Moseley GL, Hodges PW. Is 'ideal' sitting posture real?: Measurement of spinal curves in four sitting postures. Manual Therapy. 2009;14(4):404-8. 7. Williams MM, Hawley JA, McKenzie RA, van Wijmen PM. A comparison of the effects of two sitting postures on back and referred pain. Spine. 1991;16(10):1185-91. 8. Dankaerts W, O'Sullivan P, Burnett A, Straker L. Differences in sitting postures are associated with nonspecific chronic low back pain disorders when patients are subclassified. Spine [Internet]. 2006; 31(6):[698-704 pp.]. 9. Park RJ, Tsao H, Claus AP, Cresswell AG, Hodges PW. Recruitment of Discrete Regions of the Psoas Major and Quadratus Lumborum Muscles Is Changed in Specific Sitting Postures in Individuals With Recurrent Low Back Pain. Journal of Orthopaedic and Sports Physical Therapy. 2013;43(11):833-40. 10. Troup JD. Driver's back pain and its prevention: A review of the postural, vibratory and muscular factors, together with the problem of transmitted road-shock. Appl Ergon. 1978;9(4):207-14. 11. Lyons J. Factors contributing to low back pain among professional drivers: a review of current literature and possible ergonomic controls. Work. 2002;19(1):95-102. 12. Krause N, Ragland DR, Greiner BA, Fisher JM, Holman BL, Selvin S. Physical workload and ergonomic factors associated with prevalence of back and neck pain in urban transit operators. Spine. 1997;22(18):2117-26. 13. Lis AM, Black KM, Korn H, Nordin M. Association between sitting and occupational LBP. Eur Spine J. 2007;16(2):283-98. 14. Pretorius A, Keating JL. Validity of real time ultrasound for measuring skeletal muscle size. Phys Ther Rev. 2008;13(6):415-26. 15. Chen JC, Chang WR, Chang W, Christiani D. Occupational factors associated with low back pain in urban taxi drivers. Occ Med (Oxford). 2005;55(7):535-40. 16. Okunribido OO, Magnusson M, Pope MH. Low back pain in drivers: The relative role of whole-body vibration, posture and manual materials handling. J Sound Vib. 2006;298(3):540-55. 17. Okunribido OO, Magnusson M, Pope MH. The role of whole body vibration, posture and manual materials handling as risk factors for low back pain in occupational drivers. Ergonomics. 2008;51(3):308-29. 18. Okunribido OO, Shimbles SJ, Magnusson M, Pope M. City bus driving and low back pain: a study of the exposures to posture demands, manual materials handling and whole-body vibration. Appl Ergon. 2007;38(1):29-38. 19. Sakakibara T, Kasai Y, Uchida A. Effects of driving on low back pain. J Occup Med (Oxford). 2006;56(7):494-6. 20. Tamrin SBM, Yokoyama K, Jalaludin J, Aziz NA, Jemoin N, Nordin R, et al. The association between risk factors and low back pain among commercial vehicle drivers in Peninsular Malaysia: a preliminary result. Ind Health. 2007;45(2):268-78. 21. Bovenzi M, Rui F, Negro C, D'Agostin F, Angotzi G, Bianchi S, et al. An epidemiological study of low back pain in professional drivers. J Sound Vib. 2006;298(3):514-39. 22. Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. Ann Intern Med. 2009;151(4):264-9. 23. Pope M, Magnusson M, Lundstrom R, Hulshof C, Verbeek J, Bovenzi M. Guidelines for whole-body vibration health surveillance. J Sound Vib. 2002;253(1):131-67. 24. Kuorinka I, Jonsson B, Kilbom A, Vinterberg H, Biering-Sorensen F, Andersson G, et al. Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms. Appl Ergon. 1987;18(3):233-7.


25. Bridger RS, Groom MR, Jones H, Pethybridge RJ, Pullinger N. Task and postural factors are related to pack pain in helicopter pilots. Aviat Space Environ Med. 2002;73(8):805-11. 26. Massaccesi M, Pagnottaa A, Soccettia A, Masalib M, Masieroc C, Grecoa F. Investigation of work-related disorders in truck drivers using RULA method. Appl Ergon [Internet]. 2003; 34(4):[303-7 pp.]. 27. Bovenzi M, Zadini A. Self-reported low back symptoms in urban bus drivers exposed to whole-body vibration. Spine. 1992;17(9):1048-59. 28. Bovenzi M, Betta A. Low-back disorders in agricultural tractor drivers exposed to whole body vibration and postural stress. Appl Ergon. 1994;25(4):231-41. 29. Bovenzi M. A longitudinal study of low back pain and daily vibration exposure in professional drivers. Ind Health [Internet]. 2010; 48(5):[584-95 pp.]. Available from: https://www.jstage.jst.go.jp/article/indhealth/48/5/48_MSWBVI-02/_article. 30. Okunribido OO, Magnusson M, Pope MH. Delivery drivers and low-back pain: A study of the exposures to posture demands, manual materials handling and whole-body vibration. Int J Ind Ergonom. 2006;36(3):265-73. 31. Damkot DK, Pope MH, Lord J, Frymoyer JW. The relationship between work history, work environment and low-back pain in men. Spine. 1984;9(4):395-9. 32. Liira JP, Shannon HS, Haines TA. Long-term back problems and physical work exposures in the 1990 Ontario Health Survey. American Journal of Public Health. 1996;86(3):382-7. 33. Charry E, Umer M, Taylor S. Design and validation of an ambulatory inertial system for 3-D measurements of low back movements. The Meeting of Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP); 2011 Dec. 6-9; Adelaide, South Australia2011. p. 58-63. 34. Ronchi AJ, Lech M, Taylor NF, Cosic I. Reliability study of the new back strain monitor based on clinical trials. the meeting of the 30th Annual Institute of Electrical and Electronics Engineers International Engineering in Medicine & Biology Society (IEEE EMBS) Conference; Vancouver, British Columbia, Canada2008. 35. Kent P, Laird R, Haines TP. The effect of changing movement and posture using motion-sensor biofeedback, versus guidelines-based care, on the clinical outcomes of people with sub-acute or chronic low back pain-a multicentre, cluster-randomised, placebo-controlled, pilot trial. BMC Musculoskelet Disord. 2015;16(131):1-19. 36. Hill AB. The environment and disease; Association or causation? Proceedings of the Royal Society of Medicine [Internet]. 1965; 58(295-300). Available from: http://www.ncbi.nlm.nih.gov/pubmed/14283879?dopt=Abstract&holding=f1000,f1000m,isrctn.

http://www.jstage.jst.go.jp/article/indhealth/48/5/48_MSWBVI-02/_article

http://www.ncbi.nlm.nih.gov/pubmed/14283879?dopt=Abstract&holding=f1000,f1000m,isrctn


Appendix

Results of Assessment by Modified Reliability Quality Assessment Tool

The articles were assessed for the presence of bias using a modified Reliability

Quality Assessment Tool. The tool is presented in Section 2.3 (Table 1). Table 3

presents the results for each article.

Head

Author

Year Criteria

1

(Yes/N

o)

Criteria

2

(Yes/N

o)

Criteria

3

(Yes/N

o)

Criteria

4

(Yes/N

o)

Criteria

5

(Yes/N

o)

Criteria

6

(Yes/N

o)

QA

Score

Bovenzi 2006 Yes No No No No Yes 2/6

Chen 2005 Yes Yes No No No Yes 3/6

Okunribid

o

2006 No No No Not

Stated

Not

Stated

Yes 1/6

Okunribid

o

2007 No Yes No No Not

Stated

No 1/6

Okunribid

o

2008 No Not

Stated

No Not

Stated

Not

Stated

Yes 1/6

Sakakibar

a

2006 Yes No Yes No No Yes 3/6

Tamrin 2006 No No No No No Yes 1/6


Appendix B: Methodology Manuscript

Lumbar flexion during driving:

Establishing a methodology for

characterising real-time posture

data collected by innovative

technology

Sarah Tinitali, BPhysio(Hons)a, Terry Haines PhDa,b, Kelly-Ann Bowles PhDa,b

aDepartment of Physiotherapy, School of Primary Health Care, Faculty of Nursing,

Medicine and Health Sciences, Monash University Peninsula Campus, McMahons

Road, Frankston, Victoria, Australia 3199,

bAllied Health Research Unit, Kingston Centre, 400 Warrigal Road, Cheltenham,


Corresponding Author:

Kelly-Ann Bowles

Allied Health Research Unit, Kingston Centre, 400 Warrigal Road, Cheltenham,


[email protected]

Ph: +61 425 261 585

Conflicts of Interest and Source of Funding: Data analysed by this study were collected

in an observational pilot trial funded by the Institute for Safety, Compensation, and


Recovery Research (ISCRR), which represents WorkSafe, the Transport Accident

Commission and Monash University. The authors analysed the results of this research

independently of the funding bodies and no funder had any influence on how these

data were presented or conclusions reached.


Keywords:

Driving

Car

Sitting

Posture

Lumbar

Low back

Lumbar flexion

Real-time

Test-retest reliability measures

Analysis

Low back pain

Occupation

Work

Level of Evidence:

Level 3


Structured Abstract:

Study Design: Test-retest reliability study nested within a prospective cohort study.

Objective: To determine a methodology for the analysis of real-time occupational

driving posture data in the low back pain population.

Summary of Background Data: Occupational driving and poor posture have been

reported to be associated with low back pain. The association of working in a flexed

posture and low back pain has also been discussed. The link between driving posture

and low back pain is yet to be defined due to the lack of studies in the field using

validated and reliable driving posture measurement tools. Reliable and validated real-

time measurement tools are now available, yet reliable methods of analysis of these

data are yet to be established.

Methods: 10 occupational drivers completed a typical work shift while fitted with an

inertial motion sensor system (ViMove). Real-time lumbar flexion data were extracted,

with comparison of the test-retest reliability of mean lumbar flexion, peak lumbar

flexion, and standard deviation of lumbar flexion analysed at different times across a

work shift, and in different sections within a drive.

Results: Mean lumbar flexion was highly repeatable over numerous drives in one day.

Analysis of mean lumbar flexion within sections of drives revealed increased test-

retest reliability if the first five minutes of driving data were excluded. Peak lumbar

flexion had acceptable test-retest reliability over numerous drives in one day, while

standard deviation of lumbar flexion was not a repeatable measure.

Conclusions: Mean lumbar flexion was a reliable outcome for characterising driving

posture in occupational drivers with low back pain. Peak lumbar flexion may be used


if appropriate to the individual study aim. The use of standard deviation of lumbar

flexion as a posture outcome is not recommended.

Key Points:

1. Measures of mean lumbar flexion were highly repeatable across a work shift

2. The reliability of mean lumbar flexion within a drive was improved when the first

five minutes of driving data were excluded

3. Peak lumbar flexion has acceptable reliability over multiple drives, yet was not as

reliable as mean lumbar flexion

4. Standard deviation of lumbar flexion as a representation of movement either side

of a sustained posture was not a reliable measure of posture, and was therefore

not recommended for future analyses of driving posture


Mini Abstract/Précis

A reliable method of driving posture analysis using high quality measurement tools is

yet to be established. This study determined that mean lumbar flexion collected from

five minutes after the commencement of a drive provides the most repeatable outcome

of posture analysis.


Introduction

Low back pain is the major contributor to worldwide disability. The 2010 Global Burden

of Disease Study reported it to be responsible for the greatest years lost due to

disability (YLD) compared to any other condition.(1) The burden of low back pain is

increasing. Between 1990 and 2010, disability-adjusted life years (DALYs) caused by

low back pain increased from 58.2 million (95% CI 39.9 – 78.1 million) to 83 million

(95% CI 56.6 – 111.9 million).(1) In 2010, an estimated 21.7 million DALYs caused by

low back pain were as a result of ergonomic factors associated with occupation.(2)

The interplay of occupational risk factors such as heavy lifting, repetitive movements,

and non-neutral body postures have been reported to be responsible for 37% of

worldwide low back pain.(3) A study on upright working posture reported an

association between low back pain and lumbar flexion, with extreme flexion associated

with increased risk of low back pain.(4) Unlike lumbar flexion, the relationship between

low back pain and working in a position of lumbar rotation was only apparent after

additional analyses.(4)

Studies measuring sitting posture and its relationship with low back pain are reported

in the literature.(5-8) Extended time spent driving an automobile has also been linked

to low back pain,(9) with papers listing factors present during driving such as whole-

body vibration and awkward postures as risk factors for the condition.(10) Current

research typically measures driving posture with cross-sectional questionnaires or

external observation, however studies have shown these measurement methods are

flawed.(11, 12) The association between driving posture and low back pain currently


remains unknown, due to the use of posture measurement techniques with unknown

validity and reliability.(12-18)

Innovative tools are now available that are capable of measuring driving posture in

real-time in a validated and reliable way.(19, 20) A current major limitation in any study

measuring driving posture, however, is the lack of established methodology for the

analysis of collected data. Studies of kinematic analysis typically compare the test-

retest reliability of mean or peak values.(21) Current research has indicated that

lumbar flexion of greater than 60° for more than 5% of a work shift can be associated

with the development of low back pain,(4) and that end range positions may put

structures of the lower back at risk of injury.(22) Studies have also reported the

negative effect that sustained postures can have on the lumbar spine.(23) These

posture outcomes could be used to characterise driving posture, but which outcome

is the more reliable? The effects of time on driving posture over a work shift and

whether a driver takes time to settle into a driving posture after beginning a drive must

also be determined for future analyses.

In order to progress the field of low back pain and its risk factors, methods to measure,

report and classify driving posture data in this pain population are essential. The aim

of this study was to determine a methodology for the analysis of real-time posture data

in occupational drivers with low back pain.


Materials and Methods

Ethics approval was obtained from the Monash University Human Research Ethics

Committee (Approval No. CF13/3300 – 2013001717). All participants gave informed

consent. A test-retest reliability study nested within a prospective cohort study was

performed that analysed control group data collected from an observational pilot trail.

Ten occupational drivers were recruited by an expression of interest email sent to all

staff at Monash University and Monash Health, Victoria, Australia. Participants

registered their interest, and were included if they met all eligibility criteria.

Eligible participants included adults with self-reported low back pain who spend at

least two-hours of accumulated time driving a car on standard public roads for their

occupation. Participants excluded from the study were people who did not report low

back pain or discomfort when driving their vehicle; those with insidious or serious

pathologies of the lumbar spine, or conditions of the spinal cord; pregnant women;

those who participate in large amounts of manual labour or heavy lifting as part of their

job; and those who have an allergy to tape or glue. In addition, people who drove non-

standard occupational vehicles during their work shift (e.g. bus, truck or train) were

excluded due to the presence of confounding factors that have the potential to affect

driving posture. Participants received reimbursement for their time and a report of their

individual results at the end of the study.

Data were collected using the ViMove (dorsaVi, Melbourne, Australia), a wireless

inertial 3-D measurement system. This system has demonstrated good agreement

when validated against high quality motion sensor measurement tools such as the NDI


Optotrak (0.9° [95% CI =± 1.8°] root mean square error),(20) and has excellent

reliability in measurement of lumbar flexion (inter-tester reliability ICC 0.95, intra-tester

reliability ICC 0.99).(19) The ViMove has demonstrated superior reliability in

measurement of lumbar flexion compared to other tools.(19) The system includes

small sensors that are adhered to the lower back (Figure 1), and has a collection

frequency of 20Hz.(20) A detailed description of the ViMove and its application has

been described elsewhere.(24)

The ViMove was fitted to each participant by a biomechanist trained in the operation

of the system. Lumbar spine motion was measured while participants completed a

driving work shift. It was expected that participants would enter and exit their vehicle

multiple times during the shift, as they performed occupational-specific tasks. Data

from multiple drives for each participant were therefore collected.

Figure 1: ViMove System (Kent et al., 2015)


At the end of the shift, real-time data were extracted from the ViMove feedback device

to the ViMove LIVE software where it was plotted in graphical format (Figure 2). Entry

into and exit out of the vehicle were determined by a peak flexion and then extension

immediately prior to and post a section of sitting in the presence of vibration. Entry and

exit points for each drive were determined by two independent assessors. Data

present from 30 seconds after entering a vehicle until 30 seconds prior to exiting a

vehicle were nominated as driving data.

Figure 2: ViMove LIVE Software graphical representation


Three drives of at least 15 minutes in duration were randomly selected for each

participant and exported into an Excel v14.5.5 spreadsheet (Microsoft Corp;

Washington, USA). Three outcomes were calculated for further analysis: 1) mean

lumbar flexion; 2) peak lumbar flexion; and 3) standard deviation of lumbar flexion

(indication of deviation from sustained posture). Outcomes were calculated for multiple

intervals and sections for each of the participant drives, and summarised in a table

(Table 1) in preparation for entry into analysis software.

Interval

Section A) 30-sec B) 1-min C) 5-mins

1) 0-5-mins 1 1 1

2 2 2

3 3 3

2) 0-10-mins 1 1 1

2 2 2

3 3 3

3) 10-15-mins 1 1 1

2 2 2

3 3 3

Total Drive

1

2

3

Table 1: Sample table for driving data for one participant drive

1 = Mean lumbar flexion, 2 = Peak lumbar flexion, 3 = Standard deviation of lumbar flexion


Data Analysis

All statistics were completed using SPSS Inc. v23.0 (IBM Corp; Armonk, NY). A two-

way random intraclass correlation (ICC[2,1]) with absolute agreement was calculated

to determine the reliability of each outcome. Analyses were performed between three

drives over a work shift, sections of drives, and intervals of drives. Intraclass

correlation (ICC[2,1]) coefficient scores less than 0.69 were deemed poor, 0.70-0.89

acceptable, and greater than 0.90 excellent test-retest reliability.

Results

All drivers except one were employed in the health industry and drove standard

vehicles on metropolitan bitumen roads during their work shift. The mean age of

participants was 36.5 years, and 9 of the participants were female.

Analysis of mean lumbar flexion across multiple drives within a work shift revealed

excellent test-retest reliability (ICC[2,1]=0.95 [95% CI 0.84-0.99]). Peak lumbar flexion

had acceptable test-retest reliability (ICC[2,1]=0.76 (0.91 [95% CI 0.35-0.94]),

whereas the test-retest reliability of the standard deviation of lumbar flexion across

multiple drives was poor (ICC[2,1]=-0.07 [95% CI -2.68-0.73]). Due to this poor test-

retest reliability, no further analyses were performed for this outcome.

Analyses for sections within a drive were then completed, with analysis of Sections 1-

3 (0-15-minutes of driving) demonstrating acceptable test-retest reliability of mean

lumbar flexion (ICC[2,1]=0.77 [95% CI 0.31-0.94]) and excellent test-retest reliability


of peak lumbar flexion (ICC[2,1]=0.91 [95% CI 0.74-0.98]). After visual inspection of

mean lumbar data (Figure 3), it appeared that data within Section 1 (0-5 minutes of a

drive) were highly variable compared to data within Sections 2-3 (5-15 minutes of a

drive). Analysis of mean lumbar flexion was then repeated with Section 1 excluded,

resulting in an ICC[2,1] coefficient of 0.96 (95% CI 0.82-0.99).

Further analyses were then performed for intervals within a drive. The test-retest

reliability of mean lumbar flexion for intervals A, B and C were allexcellent (Table 2).

Analysis of peak lumbar flexion during driving intervals revealed excellent test-retest

reliability within Interval B (one minute of driving), and an acceptable test-retest

reliability within Interval A (30 seconds of driving). Results of all analyses are

presented in Table 2.

A power analysis for this study demonstrated that having 10 subjects provides 80%

power to detect a correlation coefficient of 0.71.(25)

Figure 3: Mean lumbar flexion within sections of a drive


Mean Lumbar Flexion (95% CI Interval)

Peak Lumbar Flexion (95% CI Interval)

SD of Lumbar Flexion (95% CI Interval)

Over 3 Drives 0.95 (0.84-0.99) 0.76 (0.35-0.94) -0.07 (-2.68-0.73)

Sections 1-3 0.77 (0.31-0.94) 0.91 (0.74-0.98)

Section 2-3 0.96 (0.82-0.99) 0.44 (-1.54-0.86)

Interval A 0.96 (0.82-0.99) 0.83 (0.34-0.96)

Interval B 0.94 (0.76-0.98) 0.95 (0.80-0.99)

Interval C 0.96 (0.82-0.99) 0.45 (-1.27-0.86)

Table 2: Results of intraclass correlation analyses on posture outcomes

during different times within and over drives

SD = Standard Deviation.


Discussion

This is the first study published in the scientific literature to establish a methodology

for analysing real-time driving posture data. The results of this study have shown that

a number of the outcome measures had excellent or acceptable test-retest reliability,

indicating that this method is a reliable method for future analyses of lumbar flexion

while driving.

Mean lumbar flexion was the most repeatable driving posture outcome, with excellent

test-retest reliability across multiple drives during a work shift, and within sections of a

drive if the first 5 minutes of driving data are excluded. When determining the amount

of data to analyse, the excellent test-retest reliability within Interval A indicates that

analysis of 30 seconds of driving posture data is sufficient when characterising driving

posture with mean lumbar flexion.

Previous research has demonstrated the importance of investigating lumbar flexion

while driving.(13-17) Although Tamrin et al.(17) suggested having a “straight back”

resulted in a lower risk of low back pain, direct measurement of the degree of lumbar

flexion was not performed in their research. This cross-sectional/observational study

videoed participants while they completed a driving shift, with no numerical

measurement of lumbar flexion collected. Previous research has shown that external

observational can only detect large magnitudes of positional change, even when

expert measurement is performed.(11) Measurement tools that are capable of

capturing minimal changes in position are therefore needed when measuring an


outcome such as driving posture. Using the methods presented by this paper, claims

made by researchers such as Tamrin et al.(17) can be studied, using direct numerical

measurement of lumbar flexion with increased accuracy.

Peak lumbar flexion had acceptable test-retest reliability across multiple drives in a

work shift. Analysis of one minute of posture data revealed excellent peak lumbar

flexion test-retest reliability compared to analyses of intervals of different durations.

The reduced quality of test-retest reliability of peak lumbar flexion in comparison to

mean lumbar flexion was expected. Peak lumbar flexion, as the name suggests,

represents a once-off extreme movement towards end of range. Analysis showed,

however, that the use of peak values had acceptable test-retest reliability, and could

be used by researchers if appropriate to the individual research aim.

Previous investigations of lumbar spine posture and its association with pain while

driving have not sought to directly measure lumbar spine posture.(12-18) In vitro

studies have reported prolapse of the intervertebral disc to occur when simulation of

the spinal column lifting an object while in flexion beyond their range of movement

(hyperflexion) is performed.(22) That is, individuals with reduced lumbar range of

movement as the result of a stiff spinal column may be at risk of disc prolapse when

they move into lumbar flexion that exceeds their normal range of movement.(22)

Although this research did show that the degree of lumbar flexion that corresponds to

the failure point of anatomical components of the spine varies, this research did

measure flexion angles. The findings of our research have shown that peak lumbar

flexion, possibly nearing dangerous levels for some individuals, can be accurately


measured and reliably analysed.

Poor test-retest reliability was present when examining the outcome of standard

deviation of lumbar flexion. This outcome was examined as previous researchers have

hypothesized that holding a sustained posture for extended periods may cause lower

back pain.(23) This would have been indicated by having a lower standard deviation

in lumbar spine motion measures. However, the lower test-retest reliability of this

measure would suggest that at this stage, this outcome is not appropriate for

comparative analyses.

No research to date conducted during occupational driving in a low back pain

population has clearly indicated the timing of their driving posture analysis. Although

some researchers briefly describe their data collection, no research indicated if a

‘settling time’ was allowed, or if driving posture data collected early or late in a work

shift differed from each other. Some researchers have suggested that time spent

driving may be associated with low back pain,(16, 18) yet no study has investigated

the effect of fatigue during a driving work shift on lumbar flexion. Our results have

shown that for our cohort, test-retest reliability of mean lumbar flexion between multiple

drives across a day was excellent, suggesting that mean lumbar flexion remains

consistent throughout a driving work shift.

This study has its limitations. The use of only lumbar flexion movement is unlikely to

be sufficient to characterise driving posture. Driving activities such as performing a

head-check when changing lanes, are likely to incorporate a component of lumbar


rotation. Lumbar rotation has been reported to be associated with low back pain, albeit

not as clearly as lumbar flexion.(4) The ViMove system was selected for the

measurement of driving posture due to its excellent validity and reliability in the

measurement of lumbar flexion.(19, 20) At the time of data collection, the ViMove was

not capable of measuring lumbar rotation. Improvements in technology have enabled

the system to now be capable of measuring this movement (software v5.9.10336.0).

Further studies that establish a methodology for the analysis of lumbar rotation during

occupational driving would be beneficial to this field of research.

The method of excluding 30 seconds of data either side of driving data to account for

postures assumed as a participant enters and exits a vehicle has not been validated.

This method was utilised to minimize analysis on non-driving postures. It is possible,

however, that participants began driving within this 30 second period, or spent longer

than 30 seconds sitting with the motor running before exiting the vehicle.

The use of a small sample (n=10) may be considered to be a limitation in this research.

Smaller samples generally have wider confidence intervals surrounding their reliability

coefficients. Our analyses identified significant ICC values for several of the outcomes

examined, indicating that the sample size was sufficient to achieve the aim of this

study.

This paper provides a methodology for the classification and analysis of real-time

lumbar flexion data during driving. Based on the results, we recommend that driving

posture data be represented by mean lumbar flexion, collected at any time within a


work shift, but not within the first five minutes of any drive. Peak lumbar flexion showed

weaker test-retest reliability in comparison to mean lumbar flexion, but did

demonstrate at least acceptable levels of test-retest reliability. Measuring the standard

deviation of lumbar flexion showed poor test-retest reliability and the use of this

outcome cannot be recommended at this time.

As the reliability of these measures has now been illustrated, future studies can be

completed that consider the relationship of lumbar flexion angle while driving and low

back pain, or comparative studies investigating the effects of interventions on lumbar

flexion while people with low back pain are driving. This methodology may be

transferable to analysis of driving posture in populations without low back pain, and

sitting posture in non-driving occupations. Further studies are required using the data

collection and analysis methods described by this study, before the reliability of this

methodology in other populations can be established.


References

1. Hoy D, March L, Brooks P, Blyth F, Woolf A, Bain C, et al. The global burden of low back pain: estimates from the global burden of disease 2010 study. Ann Rheum Dis. 2014;73(6):968-74. 2. Driscoll T, Jacklyn G, Orchard J, Passmore E, Vos T, Freedman G, et al. The global burden of occupationally related low back pain: estimates from the Global Burden of Disease 2010 study. Ann Rheum Dis. 2014;73(6):975-81. 3. Punnett L, Pruss-utun A, Nelson DI, Fingerhut MA, Leigh J, Tak S, et al. Estimating the global burden of low back pain attributable to combined occupational exposures. Am J Ind Med. 2005;48(6):459-69. 4. Hoogendoorn WE, Bongers PM, De Vet HC, Douwes M, Koes BW, Miedema MC, et al. Flexion and rotation of the trunk and lifting at work are risk factors for low back pain: results of a prospective cohort study. Spine. 2000;25(23):3087-92. 5. Park RJ, Tsao H, Claus AP, Cresswell AG, Hodges PW. Recruitment of Discrete Regions of the Psoas Major and Quadratus Lumborum Muscles Is Changed in Specific Sitting Postures in Individuals With Recurrent Low Back Pain. J Orthop Sports Phys Ther. 2013;43(11):833-40. 6. Claus AP, Hides JA, Moseley GL, Hodges PW. Is 'ideal' sitting posture real?: Measurement of spinal curves in four sitting postures. Man Ther. 2009;14(4):404-8. 7. Williams MM, Hawley JA, McKenzie RA, van Wijmen PM. A comparison of the effects of two sitting postures on back and referred pain. Spine. 1991;16(10):1185-91. 8. Dankaerts W, O'Sullivan P, Burnett A, Straker L. Differences in sitting postures are associated with nonspecific chronic low back pain disorders when patients are subclassified. Spine. 2006;31(6):698-704. 9. Kelsey JL. An epidemiological study of the relationship between occupations and acute herniated lumbar intervertebral discs. Int J Epidemiol. 1975;4(3):197-205. 10. Lis AM, Black KM, Korn H, Nordin M. Association between sitting and occupational LBP. Eur Spine J. 2007;16(2):283-98. 11. Passier LN, Nasciemento MP, Gesch JM, Haines TP. Physiotherapist observation of head and neck alignment. Physiother Theory Pract 2010;26(6):416-23. 12. Okunribido OO, Shimbles SJ, Magnusson M, Pope M. City bus driving and low back pain: a study of the exposures to posture demands, manual materials handling and whole-body vibration. Appl Ergon. 2007;38(1):29-38. 13. Bovenzi M, Rui F, Negro C, D'Agostin F, Angotzi G, Bianchi S, et al. An epidemiological study of low back pain in professional drivers. J Sound Vib. 2006;298(3):514-39. 14. Okunribido OO, Magnusson M, Pope MH. Low back pain in drivers: The relative role of whole-body vibration, posture and manual materials handling. J Sound Vib. 2006;298(3):540-55. 15. Okunribido OO, Magnusson M, Pope MH. The role of whole body vibration, posture and manual materials handling as risk factors for low back pain in occupational drivers. Ergonomics. 2008;51(3):308-29. 16. Chen JC, Chang WR, Chang W, Christiani D. Occupational factors associated with low back pain in urban taxi drivers. Occup Med (Oxf). 2005;55(7):535-40. 17. Tamrin SB, Yokoyama K, Jalaludin J, Aziz NA, Jemoin N, Nordin R, et al. The association between risk factors and low back pain among commercial vehicle drivers in peninsular Malaysia: a preliminary result. Ind Health. 2007;45(2):268-78. 18. Sakakibara T, Kasai Y, Uchida A. Effects of driving on low back pain. Occup Med (Oxf). 2006;56(7):494-6. 19. Ronchi AJ, Lech M, Taylor NF, Cosic I, editors. A reliability study of the new Back Strain Monitor based on clinical trials. Conference Proceedings of the Institute of Electrical and Electronics Engineers Engineering in Medicine and Biology Society; 2008; Vancouver, British Columbia, Canada: Insitute of Electrical and Electronics Engineers. 20. Charry E, Umer M, Taylor S. Design and validation of an ambulatory inertial system for 3-D measurements of low back movements. . The meeting of Intelligent Sensors, Sensor Networks and Information Processing (ISSNIP); Adelaide, South Australia2011. 21. Lange GW, Hintermeister RA, Schlegel T, Dillman CJ, Steadman JR. Electromyographic and kinematic analysis of graded treadmill walking and the implications for knee rehabilitation J Orthop Sports Phys Ther. 1996;23(5):294-301. 22. Adams MA, Hutton WC. Prolapsed intervertebral disc. A hyperflexion injury. Spine. 1982;7(3):184-91.


23. Little JS, Khalsa PS. Human lumbar spine creep during cyclic and static flexion: creep rate, biomechanics, and facet joint capsule strain. 33. 2005;3(391-401). 24. Kent P, Laird R, Haines TP. The effect of changing movement and posture using motion-sensor biofeedback, versus guidelines-based care, on the clinical outcomes of people with sub-acute or chronic low back pain-a multicentre, cluster-randomised, placebo-controlled, pilot trial. BMC Musculoskelet Disord. 2015;16(131):1-19. 25. Portney LG, Watkins MP. Foundations of Clinical Research: Pearson New International Edition: Applications to Practice. Harlow, Essex: Pearson Education Limited; 2014.

www.iscrr.com.au

067 seating modification, back posture

Documents