athletic assistive technology for persons with physical ......sports: athletics, powerlifting,...

Athletic Assistive Technology for Persons withPhysical Conditions Affecting Mobility

David Hill, BS, MS, Donna Moxley Scarborough, BS, MS, PT, Eric Berkson, BA, MA, MD, Hugh Herr, BA, MS, PhD

ABSTRACTRecent advances in technology have allowed athletes with physical conditions to perform at increasingly high levels. Afterthe ruling that one such athlete had an advantage over ‘‘able-bodied’’ athletes before the 2008 Olympics, many questionwhether these technological advances have even augmented athletic abilities. Although much progress has been achieved,technology for ‘‘disabled’’ athletes must be far advanced to allow them to reach and surpass the ability level of able-bodiedathletes. Here, we review the current state of assistive devices created to assist athletes with physical conditions affecting theirmobility. We form a quantitative comparison between athletes with and without physical conditions, lay out recent ad-vancements in the development of sports-related assistive devices, and discuss the implications of these devices. Using theParalympics as a guide, this work serves as an overview of the current state of assistive technology for athletes with mobilityconditions and a tool for future researchers attempting to bridge the gap between athletes with and without physicalconditions. (J Prosthet Orthot. 2014;26:154Y165.)

KEY INDEXING TERMS: assistive technology, prosthesis, wheelchair, sports, Paralympics, athletes with physical conditions,athletes with mobility conditions, disability

In 2008, the International Association of Athletics Federa-tions (IAAF) began a worldwide debate when they establishedRule 144.2(e), prohibiting the use of technical devices that

offer a competitive advantage.1 Specifically citing springs as ad-vantageous, this rule resulted in the immediate disqualificationof Oscar Pistorius, the South African bilateral amputee sprintervying to become the first amputee to competewith ‘‘able-bodied’’runners at the highest level. Extensive trials and investigationresulting from this ruling caused its eventual repeal,2,3 allow-ing Oscar Pistorius to make history as the first-ever amputeesprinter to compete in the Olympics. The initial verdict evokedsome pivotal research in sports performance enhancement forathletes with mobility conditions (AMCs), and a rather inter-esting question emerged:

Just how far can assistive technology enhancements takeall athletes in the future?

To examine this question, in this article, we explore the cur-rent state of para-athletics, surveying the literature to assess thepresent achievements of AMCs, and find recent advances in as-sistive technology for sports-related applications. This explora-tion provides insight into the current direction of assistive device

developments, which could contribute to a future wave of aug-mentative devices.

CONTRIBUTIONDisability is an umbrella term often used to describe a

physical or mental impairment that substantially limits one ormore major life activities and causes participation restrictionsfor an individual.4 However, using any form of this term torefer to humans is unacceptable because the ability to performat extraordinary levels can be restored given the right tech-nology, as evidenced by Oscar Pistorius. The focus of this workis athletes with physical conditions, specifically conditions thataffect limb and motor function. We discuss current work ontechnology that assists these athletes, thus directly address-ing activity and participation restrictions and improving theathlete’s ability to perform. The goal is to outline current de-sign approaches, evaluating their efficacy and potential forfuture applications.

PREVIOUS WORKSports for AMCs have made great strides since the inception

of the Paralympics approximately a half century ago.5 Withinthe last 2 decades, the Paralympics and the Olympics becamemore closely tied, resulting in a sudden surge in exposure andpopularity, as well as newfound ‘‘disabled’’ star athletes. Sincethen, much work has gone into studying sports performanceof AMCs from a variety of angles. Although many focus onthe Paralympics and its history,5Y7 others cover topics rang-ing from psychological characteristics of para-athletes to so-ciopolitical implications of para-athletics.

One of the major concerns in all sports is injury. Medicalprofessionals and athletes alike are deeply invested in study-ing the occurrences, causes, prevention, and diagnosis of in-juries. In 2009, Miller8 investigated medical issues associated

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DAVID HILL, BS, MS, and HUGH HERR, BA, MS, PhD, are affiliatedwith the Biomechatronics Group, Media Lab, Massachusetts Instituteof Technology, Cambridge, Massachusetts.

DONNA MOXLEY SCARBOROUGH, BS, MS, PT, and ERIC BERKSON,BA, MA, MD, are affiliated with the Mass General Sports PerformanceCenter, Department of Orthopaedic Surgery, Mass General Hospital,Boston, Massachusetts.

Disclosure: The authors declare no conflict of interest.

Copyright * 2014 American Academy of Orthotists and Prosthetists

Correspondence to: David Hill, BS, MS, Biomechatronics Group,Media Lab, Massachusetts Institute of Technology, 75 Amherst StE14-348U, Cambridge, MA 02139; email: [email protected]

Copyright @ 2014 by the American Academy of Orthotists and Prosthetists. Unauthorized reproduction of this article is prohibited.

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with Paralympians, discussing common injuries and illnessesencountered by these athletes. Mason9 furthered this discus-sion in 2012 when he reviewed the history of sports medicinefor AMCs, forming one of the most comprehensive assessmentsof AMC sports medicine to date. Others have examined specificoccurrences of injury to uncover where and how AMCs are mostvulnerable.10Y14

Psychological factors affecting AMC sports performance havebeen studied extensively as well. Evaluations of self-esteem, hap-piness, and other psychological factors arose as early as the 1980s,showing that there are mental benefits of sports participation forpersons with physical conditions.15 More recently, Martin16 foundthat sport experience positively affectedmotivation for youth withphysical conditions. Other reviews by Jefferies et al.,17 Deanset al.,18 and Martin19 emphasize the growing importance ofsports psychology for AMCs. As a result, new methodologies forproviding sufficient psychological assessments toAMCsby sportspsychologists have arisen.20

Social and political issues are the focus of an overwhelm-ing majority of publications concerning athletes with physicalconditions. Often, these are related to civil rights, accessibility,and unfair treatment. One such example is the disparity in me-dia coverage for para-athletes when compared with able-bodiedathletes. Traditional media sources have failed to give equalcoverage to AMCs, and when they do, the language used hascommonly been perceived as negative and offensive.21,22 Fur-ther, some have criticized the ‘‘disempowerment’’ of para-athletesunderlying the structure of competition. A clear separation fromtheOlympics, substantial fundingdifferences, anddisparatemediacoveragemake theParalympics, and equivalently AMC sports, lessinclusive than it is often stated and intended to be.22Y27

To our knowledge, few academic publications have reviewedassistive technology for AMCs. Burkett28 recently conductedtwo such reviews, one examining technology used exclusivelyin summer Paralympic competitions and a secondary piece fo-cusing on technology for the winter Paralympics.29 In addition,Magdalinski30 briefly discussed assistive sports technology in a2012 review of prostheses and artificial skins. Previous studiesof assistive devices for sports mostly focus on prostheses or ex-clusively Paralympic technology. Here, we review the currentstate of para-sports performance and many devices built to aidathletes with mobility conditions, using the Paralympics as astarting point and method for evaluating the impact of assistivetechnology.

PARA-ATHLETE PERFORMANCEOne way to evaluate the current state of para-sports per-

formance is to assess the Paralympic Games, analyzing itshistory and comparing it with the Olympics. Although Inter-national Paralympic Committee (IPC) regulations, which havethe potential to limit improvements in athletic performance, pro-hibit the use of certain assistive devices, this analysis doesoffer some indirect insight into the state of assistive sportstechnology and its ability to facilitate world-class athleticachievement. The Paralympics is the Olympic-equivalent

worldwide sports competition for athletes with conditions thataffect athletic ability. It officially began in 1960. Now, it occursimmediately after the Olympics every 4 years and in the samecity.31 Examining Paralympic events gives clues to which as-sistive technologies are most advanced and useful for athleticactivities. Further, comparing the top performances in the Para-lympics and the Olympics gives a more quantitative measureof the efficacy of these technologies in matching biologicalperformance.

The Paralympics features 26 distinct events, ranging fromaquatics to wheelchair tennis. Of these, 23 coincide with Olym-pic events (see Table 1). Observing the absence of certain Olympicsports in the Paralympics offers some obvious key distinctions.Specifically, more dynamic sports with varied movements seemto be the most difficult to reproduce, especially combat sports.Even those represented in the Paralympics can be achieved onlythrough the use of wheelchairs. Perhaps, this underscores thepresent shortcomings in prosthetic devices, which tend to bemost powerful for single-plane movements.

Further disparities can be seen in the world records postedin the two competitions. The IPC tracks records only in foursports: athletics, powerlifting, shooting, and swimming.31

Table 1. Basic Olympic and Paralympic events lists

Olympics

Olympicsand

Paralympics Paralympics

Badminton Aquatics BocciaBobsleigh Archery GoalballBoxing Athletics Wheelchair dance*Golf Basketball*Gymnastics BiathlonHandball Canoe/kayakHockey Curling*Luge CyclingModern pentathalon EquestrianSkating Fencing*Taekwondo FootballWrestling Ice hockey

JudoRowingRugby*SailingShootingSkiing

Table tennisTennis*TriathlonVolleyball

Weightlifting

The first column displays competitions that are performed only in theOlympics. The second column shows events that are performed in boththe Paralympics and the Olympics. The third column shows events thatare performed in the Paralympics but not in the Olympics. *Wheelchair-only events in the Paralympics.

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Table 2 lists select aquatics and athletics records and comparespara-athlete records with equivalent Olympic athlete records.In the Paralympics, competitors are classified on the basis ofability level and/or condition type. Broadly speaking, the IPCrecognizes six condition categories: amputee, cerebral palsy,intellectual, wheelchair, visual, and les autres.31 Classificationsdiffer in every sport and follow a set of guidelines establishedand maintained by the IPC. Examples are shown in Table 2 andare defined as follows:

Aquatics(numbers move from least ability to most ability)1 to 10: Physical11 to 13: Visual14: Intellectual

Athletics11 to 13: Blind/visual20: Intellectual32 to 38: Cerebral palsy (32Y34wheelchairs, 35Y38 ambulant)40 to 46: Amputation or other condition such as dwarfism

(ambulant)51 to 58: Spinal cord injury or amputation (wheelchair)

Apparent differences exist within the classes of para-athletesand between athletes with and without physical conditions.These are highlighted by record comparisons (see Table 2).Quickly, one can see which conditions affect performance mostseverely. In particular, athletes with intellectual conditions seemto be affected the most, with world records reported only for sixathletic and aquatic events. No other condition affected athleticperformance as drastically as intellectual conditions; however,ability level is directly linked to the degree and type of conditionand differs for every sport.

Aquatic records follow in an order most would expect. Inall cases, para-athletes post slower records than Olympic ath-letes. Differences in these records tend to increase with racedistance. For example, in short 50-m races, high-level para-athletes fall short of Olympic athlete record times by justgreater than 2 seconds (10%), showing that these athletes per-form at an elite level despite the condition. However, as racesbecome longer, the disadvantages of para-athletes begin toshow more. Eventually, record time spreads increase to nearly2 minutes (13%).

On the other hand, athletics records are more interest-ing. Although they mostly follow the trends seen in aquaticscompetition, there are a few unexpected observations. As onewould anticipate, athletes without conditions typically outper-form para-athletes, especially in jumping and throwing events.However, a trend begins to arise in longer races (i.e., 800, 1,500,5,000, and 10,000 m). In these races, some para-athletes haveexceeded Olympic athlete times. The most drastic example ofthis occurs in the 10,000-m race, when the fastest para-athleteoutperformed his Olympic athlete counterpart by greaterthan 6 minutes (25%). Although this seems counterintuitiveat first glance, upon reviewing the Paralympic classifications

(see above), one can notice that each of these high-performingpara-athletes competes using a wheelchair. This gives rise totwo key observations about para-sport and the assistive de-vices that facilitate them: 1) wheelchairs are currently themost effective and versatile assistive devices and 2) all as-sistive devices fall short of consistently reproducing naturalathletic ability.

DESIGN APPROACHESDesigns of assistive devices for athletic activities depend

mostly on the sport, with each differing in the desired tasks andgoals. With this inmind, the following review of assistive devicedesign approaches is organized according to the general taskand/or sport. The section is split into five major subsections:wheeled mobility, ambulatory mobility, nonwheeled seated sport,snow and ice mobility, and aquatic mobility. Wheeled mobilitycovers advances in manual wheelchairs, cycling, and poweredwheelchairs. Ambulatorymobility includes recent developmentsin running and jumping devices for athletes with lower-limbconditions. The nonwheeled seated sport subsection discussescommonly used devices for seated track-and-field sports as wellas fishing. Snow and ice mobility covers skiing and snow-boarding technology. Finally, aquatic mobility discusses assis-tive technology for swimming and rowing.

WHEELED MOBILITYManual wheelchairs are the most widely used assistive de-

vices for athletes with ambulatory conditions by a substantialmargin. Sports conducted with them include tennis, rugby, cur-ling, and dance, to name a few. When compared with otherdevices, they tend to be more versatile and effective. Their wide-spread use has led to a number of dedicated publications.32Y36

Years of work have gone into creating ergonomic wheel-chair designs.32 To accomplish this, wheelchairs are tweakedto be lighter, faster, and more maneuverable. Advances in ma-terials and mechanisms have made this possible. Typical wheel-chairs consist of several customizable components, includingthe frame, seat, and wheels. Each one affects performance. Lightframes are essential for acceleration and upper-limb preserva-tion, seat cushions provide pressure relief for sustaineduse, handrims govern control and propulsion tasks, and casters andstraps provide stability.36Y38 Further, wheel orientation/camber(Figure 1A) has been shown to affect maneuverability,34,36,41

and seat orientation (Figure 1A) influences stability and con-trol.34,36 Decisions regarding these parameters differ on the ba-sis of sport.

Component tweaks, as described above, account for mostsport wheelchair design decisions. Although the decisions tobe made remain the same, the methods for determining themdiffer, with some even developing novel devices and experi-ments to decide.42 Others have explored dedicated designs forspecific communities.43Y45 Berger et al.43 designed a wheel-chair for basketball players in the Netherlands with a rede-signed frame to reduce weight and increase strength and analtered wheel position, angled in such a way that tire defor-mation is eliminated without sacrificing maneuverability.

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Advanced wheelchairs are often quite expensive, limiting theiruse to more wealthy countries and individuals. To combat this,Authier et al.45 developed a low-cost sport wheelchair for de-veloping nations. Wheelchair development and selection bothrequire a specialized and customizable approach based on bodytype, activity, and even location.

Para-cyclists have a choice of four different types of cycles:tandem cycles, tricycles, bicycles, and hand cycles. They all

offer distinct advantages and disadvantages, which depend onthe activity and the condition of the user. Tandem bikes aremade for two riders. There are two seats and two sets of han-dlebars. Athletes with visual conditions use these; the athletesits at the back and a ‘‘sighted pilot’’ guides from the front. Ath-letes with balance deficiencies use tricycles. The extra wheeleases balance, allowing athletes to stabilize in a way that theycannot on two wheels. Athletes with mobility conditions use

Table 2. Men’s aquatics and athletics world records

World records (men)

Aquatics

Paralympics

Event S1YS10 S11YS13 S14 Olympics

50-m Freestyle 0:23.16 0:22.99 0:20.91100-m Freestyle 0:50.87 0:50.91 0:46.91200-m Freestyle 1:54.46 1:56.78 1:58.42 1:42.00400-m Freestyle 4:04.20 3:58.78 3:40.071500-m Freestyle 16:24.63 16:33.79 14:34.1450-m Backstroke 0:28.42 0:27.57 0:24.04100-m Backstroke 1:00.01 0:56.97 1:01.85 0:51.94200-m Backstroke 2:15.04 2:18.10 1:51.9250-m Breaststroke 0:29.16 0:29.90 0:26.67100-m Breaststroke 1:04.02 1:03.91 1:06.69 0:58.58200-m Breaststroke 2:24.23 2:33.82 2:07.0150-m Butterfly 0:25.25 0:24.53 0:22.43100-m Butterfly 0:55.99 0:54.92 0:49.82200-m Butterfly 2:13.78 2:13.40 1:51.51

Athletics

Paralympics

Event 11Y13 20 32Y38 40Y46 51Y58 Olympics

100 m 0:10.46 0:10.79 0:10.72 0:13.63 0:09.58200 m 0:21.05 0:21.82 0:21.30 0:24.18 0:19.19400 m 0:47.88 0:49.33 0:45.39 0:45.07 0:43.18800 m 1:52.13 1:43.55 1:51.82 1:31.12 1:41.011,500 m 3:48.31 3:54.07 3:30.12 3:50.15 2:54.51 3:26.005,000 m 13:53.76 12:33.72 14:20.88 9:53.05 12:37.3510,000 m 30:24.88 38:12.96 30:15.35 19:50.64 26:17.534 � 100 m 0:42.46 0:44.81 0:41.78 0:49.89 0:37.044 � 400 m 3:27.89 3:38.92 3:27.00 3:05.46 2:54.29High jump 2.03 2.12 2.45 mLong jump 7.66 7.48 6.48 7.58 8.95 mTriple jump 16.23 15.20 18.29 mShot put 16.62 16.29 17.52 18.38 16.37 23.12 mDiscus throw 53.61 55.81 63.46 60.72 74.08 mJavelin 64.38 57.81 62.15 50.98 98.48 m

IPC.31

The far left column displays events. The middle columns display world records set by para-athletes. They are split on the basis of classification. For aquatics,lower numbers generally indicate less ability, whereas higher numbers indicatemore ability. The columns are split on the basis of three separate classifications:physical conditions (1Y10), visual conditions (11Y13), and intellectual conditions (14). Athletics competitors are split into five classes: blind/visual conditions(11Y13); intellectual conditions (20); cerebral palsy (32Y38), wheelchair (32Y34) and ambulant (35Y38); amputation or other conditions such as dwarfism,ambulant (40Y46); and spinal cord injury or amputation, wheelchair (51Y58). The far right column displays world records set by athletes eligible for theOlympics.


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standard bicycles, if possible. These follow the standard design,but slight modifications are sometimes made to meet the needsof the condition. Many of these modifications involve customattachments between the rider and the bike. Finally, hand cyclesare operated by hand instead of foot. Usually, the rider assumesa kneeling or lying position.31 We focus only on hand cyclesbecause either the others are beyond the scope of this article orlimited innovation exists specifically for AMCs.

Hand cycles share many of the same design goals as wheel-chairs. Like wheelchairs, hand cycles have progressed with ma-terials and designs. Further, custom component layouts are usedto optimize individual performance. This versatility can be seenin Siebert’s39 work on an adjustable chassis for a mountain handbike. As shown in Figure 1B, Siebert alters the tire layout andbuilds completely adjustable cranks, footrests, backrests, brack-ets, and drive trains to allow total customizability in off-roadconditions.

Hand cranks are unique to hand cycles and a major sourceof customization. Many have studied the performance differ-ences caused by altering them.46Y51 These studies typically re-volve around mechanical efficiency and power effects. Cranklength was studied by Goosey-Tolfrey et al.,46 who determined

that shorter crank lengths tend to be more efficient. Further,Kramer et al.47,48 analyzed the effects of crank angle and widthon performance in two separate articles, revealing that a morepronated handle offers improvements, whereas width has min-imal influence. Arnet et al.49 found that an upright backrestwith a distant crank position reduces shoulder load. Finally,van der Woude et al.34 measured the effects of gear ratio andmode on propulsion characteristics and observed a significantreduction in metabolic expenditure during synchronic arm usewith lighter gear ratios. Hand cranks are a key component ofhand cycles, and, as such, their development over the years hasled to enhanced ability.

Powered assistive sports devices are extremely uncommon.This makes sense for competitive sports, but for recreationalsports, these are needed to promote activity among popula-tions with the most serious conditions. So far, the most com-mon powered devices used for sport are paramobile devices,those that mobilize paraplegics. These often assist in sitting-to-standing transitions, and although this may sound minor,it allows paraplegics to take part in less rigorous standingactivities, such as golf.40,52 Figure 1C displays this transition.The most common commercial paramobile devices resemble

Figure 1. Manual wheelchair, hand cycle, and paramobile device. A, Wheel camber is the orientation of the wheel relative to the frame (leftcolumn). Positive camber (bottom left) creates a larger base of support and improves lateral stability, hand-rim comfort, and maneuverability.However, positive camber also increases rolling resistance, decreases seat height, and enlarges footprint/turning radius. Seat angle is the ori-entation of the seat relative to level ground (right column). Seat dump (bottom right) improves lateral stability and hand-rim accessibility, but itdecreases rearward stability and height. Both wheel camber and seat angle should be chosen appropriately to optimize individual performance,balancing their positive attributes with the negative.36 B, A hand cycle with an adjustable chassis allows the rider to adapt to off-road conditions.39

C, A paramobile device for paraplegics facilitates upright posture useful for golfing.40 Adapted from Goosey-Tolfrey36 (A), Siebert39 (B), andWucherpfennig and Boyer40 (C).


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Perk’s52 upright wheelchair and use a motorized, tiltableseat that erects the rider in a manner suitable for swinging agolf club.

AMBULATORY MOBILITYWith Oscar Pistorius’ success in the 2012 Olympics came

much coverage of lower-limb prostheses, both as praise andcriticism.53Y58 Some argue that state-of-the-art lower-limb pros-theses offer amputee athletes distinct advantages when com-pared with their able-bodied counterparts.56,57 These sentimentsdo make a statement about the progress that ambulatory pros-theses have encountered in recent years; however, they over-look the progress that remains to be made. This potential forfuture development is highlighted by the large amounts ofwork still being conducted to further develop running prosthe-ses. Table 1 shows that wheelchairs are still a very common toolfor athletes with ambulatory difficulties. Future developments inambulatory prostheses for athletes seek to open up opportunitiesfor nonwheelchair athletes that are currently unavailable. Here,we discuss recent developments.

Passive running prostheses have progressed with materials.Because modern advances in materials have caused them tobecome lighter but stronger, prostheses using these materi-als can withstand a higher load demand while not inhibitingthe wearer because of weight. In addition, recent innovationhas seen these devices become more biomimetic, but not in

appearance.59 Running prostheses, such as the ones shown inFigure 2, are made to mimic the spring-like behavior of thehuman ankle complex, specifically the Achilles tendon,3 buttheir form factor is often made to resemble that of a quadru-pedal animal.60 Using this ‘‘cheetah’’ architecture, lower-limbamputees have been able to achieve new athletic heights,3,61,62

inching closer to Olympic levels (see Table 2).In addition, alignment and residual limb to prosthesis at-

tachment continue to be problems for amputee athletes. Nomatter how advanced prostheses become, they are useless with-out suitable means to attach and align them. To address the firstissue, Burkett et al.63 studied alignment for transfemoral am-putee runners, showing that lowering the knee joint improvesrunning velocity and symmetry. New, more intimately attach-ing sockets have been produced to address the second issue.Madigan and Fillauer64 designed the 3-S Socket, a silicon suc-tion socket made for both the upper and lower limbs. Further,Tingleff and Jensen65 made an adjustable socket from carbonand polyaramid fibers that uses a slit to form a flexible flap forreadjustment. This socket is made to offer versatility for multi-ple sports, which require different socket fits. In all cases, thealignment and socket adjustments were made to optimize ath-letic performance and fit.

Presently uncommon, powered running prostheses shouldbecome more common in the future. As of now, there islimited published work. However, Huff et al.66 developed a

Figure 2. Passive lower-limb prostheses. A, Flex-Foot (Flex-Walk, Laguna Hills, CA, USA) (Modular III). B, Flex-Sprint I (Ossur, Reykjavik,Iceland). C, Flex-Sprint II (Ossur). D, Flex-Sprint III (Cheetah; Ossur). E, Flex-Run (Ossur). F, Symes-Sprint (Ossur). B to F, Specialized runningprostheses. Adapted from Lechler and Lilja.59


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running controller for a powered knee-ankle prosthesis capa-ble of reproducing some key elements of healthy running.These sorts of devices are far from commercial use, butthey will likely be the next wave of assistive devices for am-putee athletes.

Jumping requires similar assistance as running for ampu-tees. Spring-like propulsion is key. Many have studied the ef-fects of common jumping/running prostheses on performance,comparing amputee jumpers with individuals with biologicallimbs.67Y74 These studies have shown that amputees often re-plicate the techniques of biological limb jumpers but exhibitcertain compensatory mechanisms and asymmetries that leadto reduced ability.

NONWHEELED SEATED SPORTSeated sports are quite popular for AMCs. These activities

are conducted either using no technology, such as seated vol-leyball, or using adaptive chairs, such as several Paralympictossing events. Although nonwheeled seated technology sub-stantially limits mobility, it does offer stability that is difficultto achieve with wheeled devices. This is essential for sports thatrequire the athlete to form a stable base and toss an object, forexample, shot put, discus throw, and javelin.

As previously mentioned, some track-and-field competitionsrequire seated technology. Specifically, the throwing sports re-quire adaptive seats called throwing frames. Limited academicresearch has been conducted on these devices, but some havemade attempts at analyzing them to determine advantageousconfigurations for competition and classification.75,76 However,neither of these studies provides conclusive evidence to im-prove athlete performance. Others have developed more adjust-able throwing frames,77 which are hoped to enhance trainingand performance.

Fishing is another example of a seated sport that requirestechnology manipulations. This has been a significant point ofinnovation, particularly among independent inventors. Mecha-nisms have been developed to assist in holding the fishingrod,78Y80 casting,81,82 and reeling.83 Examples of these modifi-cations are shown in Figure 3. For chair users and those withupper-limb deficiencies, rod stability, power, and control arecritical issues. More recent advances continue to tackle theseproblems.84

SNOW AND ICE MOBILITYSnow and ice activities are extremely popular among AMCs.

For decades, adaptive equipment has been created to accountfor these conditions. These adaptations include outriggers/ski-tipped crutches to stabilize, stirrups for leg support, adap-tive cuffs for persons with upper-arm conditions, modified bootsand ski attachments formaneuverability, and sit skis with kayak-style poles for athletes with more severe conditions.85,86 Skiingprostheses typically focus on facilitating knee and ankle move-ment while establishing stability.87Y89 Sit skis (Figure 4), on theother hand, are designed to maintain center of mass stabilityand inertia, often using adjustable frames.90,91 These adjust-ments influence both stability and comfort.90

Prostheses for snowboarding are similar to those for skiing.Versatile leg movement is key. Joint rotation, in all planes, isessential. Minnoye and Plettenburg92 developed a transtibialsnowboarding prosthesis capable of passive inversion/eversionand plantarflexion/dorsiflexion to make amputee snowboard-ing more comparable with snowboarding with biologicallimbs. Similarly, St-Jean and Goyette93 developed a passivemulti-axis springed ankle prosthesis for ice skating to im-prove mobility for a 7-year-old figure skater. Robust multi-axisjoint prostheses are difficult to build, but they are critical forathletic performance, especially activities that involve snow orice mobility.

AQUATIC MOBILITYCompetitive swimming is commonly performed without

assistance. One example is the S3 classification, commissionedby the IPC, which allows athletes with amputations of allfour limbs to compete against one another.31 However, theredoes exist technology designed specifically to assist AMCsin swimming.

Swimming prostheses (see Figure 5) typically take the formof fin-like attachments, and many are designed to simplifynavigating the poolside.94 Some have attempted to improveupon these by making more versatile feet. Colombo et al.95 builta leg capable of both walking and swimming. The approachdescribed was an adaptable pylon ankle prosthesis capable ofbeing manipulated into a fin-like configuration. Figure 5Bshows this adaptation. Yoneyama et al.,96 on the other hand,

Figure 3. Adapted fishing rod. The rod comprises a base for stabilityand a motored reel for increased power. The fishing rod is rotatable andadjustable to aid those with mobility conditions. Adapted from Byrd.84


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developed an upper-limb prosthesis for above-elbow amputeesto better achieve balance. This group used a simulation of thecrawl stroke and an optimization method to build the upper-limb prosthesis.

Rowing is particularly difficult for athletes with upper-limbconditions.97 For amputees, these difficulties have been com-bated in a few ways. Rowing hands must maintain grasp andcontrol on the paddle while mimicking human wrist ability.98

Highsmith et al.98 studied two such examples, determiningthat the one, the TRS kayak hand (Hammerhead KayakTerminal Device, TRS Inc., Boulder, CO, USA), was forgivingof technical errors in paddling form and the other, the USFkayak hand (University of South Florida), maintained graspbetter. In 2008, adaptive rowing became a Paralympic event,enabling athletes with physical conditions to compete inrowing competitions using adapted boats.99 These boats often

Figure 5. Swimming prostheses. A, Swimming prostheses must be waterproof and durable. Fin-like attachments are used to improve leg thrust(top). Durable, rubber attachments with flat bases are used to aid in poolside navigation (bottom). B, An ankle prosthesis conforms to bothwalking and swimming. The swimming configuration angles the pylon to be better equipped for water thrust (bottom). Adapted from Saadah94

and Colombo et al.95

Figure 4. Sit ski. Sit skis are generally used by athletes with reduced lower-limb function and stability. Adapted from Cavacece et al.90


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include restraints, customizable seats, and gripping aids tofacilitate rowing for AMCs.100

DISCUSSION AND CONCLUSIONSAssistive technology ranges from simple to complicated,

and it alone does not dictate athletic performance; however,along with training enhancements, medical advances, the in-creasing popularity of the Paralympics, and several other fac-tors, it does play a large role in allowing AMCs to compete atthe highest level. As para-sports progress, we will continue tosee technological advances in assistive devices and athletespushing the boundaries of physical limitations, further blur-ring the line between what people commonly consider ‘‘dis-abled’’ and what they do not. Thus far, assistive devices havebeen key in producing new levels of performance: lower-limbamputees are competing with Olympic athletes, Paralympicrecords are dropping more rapidly than ever, and wheelchairathletes have even surpassed some Olympic records. However,there are limitations.

A look back at the event and record comparisons in Tables 1and 2 reveals the major limitation of state-of-the-art assistivetechnologies for sports. Wheelchairs are by far the most ad-vanced and widely used devices, as evidenced by the number ofwheelchair sports in the Paralympics and their positive impacton records; however, even these are vastly limited. Wheel-chairs confine height, reach, and agility. Despite their con-straints, wheelchairs clearly outperform other devices for mostParalympic events. Prostheses may be a better option going intothe future, but as of now, they do not offer the versatile move-ment capabilities of wheelchairs.

Assistive sports devices have not yet begun to take advan-tage of smart and/or powered technology. Unlike daily-usewheelchairs and prostheses that are becoming smarter by in-corporating electronics, sport devices continue to rely on ad-vancing materials and mechanical designs. This lack couldbe either due to the ethics/purity of sports or due to the dif-ficulty of producing powered devices suitable for the dynamicmotions required for sports. Moving forward, powered de-vices may begin to arise in the same way as they have forgeneral mobility. In addition, these devices will further ex-ploit the interplay of biology and engineering, closely resem-bling biology and mimicking biological function. The goalof these advancements will be for AMCs to meet and surpassthe abilities of competitors with no physical conditions.

Circling back to the original questionVjust how far canassistive technology enhancements take all athletes in thefutureVwe now see that assistive devices have a long way to gobefore they can claim augmentative capabilities. However, thetechnology described in this article and used for present-dayassistive devices does have implications in future athleticaugmentation devices. Researchers have already begun to de-velopdevices for the enhancement of dynamicmovements.101,102

The progression of these devices is directly tied to that of as-sistive devices. As assistive technology for athletes compet-ing with a physical condition advances, so will augmentative

technology for athletes without physical conditions, creatingthe athlete of the future.

ACKNOWLEDGMENTSThe authors thank all of the affiliates of the Biomechatronics Groupand Massachusetts General Hospital Sports Performance Center whoassisted in this work.

REFERENCES1. International Association of Athletics Federations. Competition

Rules 2008. Imprimerie Multiprint, Monaco, 2008.

2. Pistorius v. IAAF Arbitral Award. The Court of Arbitration forSport, Lausanne, Switzerland, May 2008.

3. Weyand PG, Bundle MW, McGowan CP, et al. The fastest runneron artificial legs: different limbs, similar function? J Appl Physiol2009;107(3):903Y911.

4. Americans With Disabilities Act of 1990, as amended. Availableat: http://www.ada.gov/pubs/adastatute08.htm#12102. AccessedJanuary 19, 2014.

5. Joukowsky AAW, Rothstein L. Raising the Bar: New Horizons inDisability Sport. Umbrage Editions, New York, NY: ConsortiumBook Sales & Dist; 2002.

6. Gold JR, Gold MM. Access for all: the rise of the ParalympicGames. J R Soc Promot Health 2007;127(3):133Y141.

7. Legg D, Emes C, Stewart D, Steadward R. Historical overview ofthe Paralympics, Special Olympics, and Deaflympics. Palaestra2004;20(1):30Y35, 56.

8. Miller S. Medical aspects of Paralympic Sport. SportEX Med2009;42:13Y20.

9. Mason F. From rehabilitation patients to rehabilitating ath-letes. In: Malcolm D, Safai P, Eds. The Social Organization ofSports Medicine: Critical Socio-Cultural Perspectives. London,UK: Routledge; 2012:77Y106.

10. Ferrara MS, Palutsis GR, Snouse S, Davis RW. A longitudinalstudy of injuries to athletes with disabilities. Int J Sports Med2000;21(3):221Y224.

11. Klenck C, Gebke K. Practical management: common medi-cal problems in disabled athletes. Clin J Sport Med 2007;17(1):55Y60.

12. BurnhamRS, May L, Nelson E, et al. Shoulder pain in wheelchairathletes: the role of muscle imbalance. Am J Sports Med 1993;21(2):238Y242.

13. Ferrara MS, Buckley WE, Messner DG, Benedict J. The injuryexperience and training history of the competitive skier with adisability. Am J Sports Med 1992;20(1):55Y60.

14. Pepper M, Willick S. Maximizing physical activity in athleteswith amputations. Curr Sports Med Rep 2009;8(6):339Y344.

15. Valliant PM, Bezzubyk I, Daley L, Asu ME. Psychological impactof sport on disabled athletes. Psychol Rep 1985;56(3):923Y929.

16. Martin JJ. Psychosocial aspects of youth disability sport. AdaptPhys Activ Q 2006;23(1):65Y77.

17. Jefferies P, Gallagher P, Dunne S. The Paralympic athlete: asystematic review of the psychosocial literature. Prosthet OrthotInt 2012;36(3):278Y289.


162 Volume 26 & Number 3 & 2014


http://www.ada.gov/pubs/adastatute08.htm#12102

18. Deans S, Burns D, McGarry A, et al. Motivations and barriersto prosthesis users participation in physical activity, exerciseand sport: a review of the literature. Prosthet Orthot Int 2012;36(3):260Y269.

19. Martin J. Mental preparation for the 2014 Winter ParalympicGames. Clin J Sport Med 2012;22(1):70Y73.

20. Bawden M. Providing sport psychology support for athletes withdisabilities. In: Dosil J, Ed. The Sport Psychologist’s Handbook.Chichester, UK: John Wiley & Sons Ltd; 2008:665Y683.

21. Tynedal J, Wolbring G. Paralympics and its athletes through thelens of the New York Times. Sports. 2013;1(1):13Y36.

22. Golden A. An analysis of the dissimilar coverage of the 2002Olympics and Paralympics: Frenzied Pack Journalism versusthe Empty Press Room. Disabil Stud Q 2003;23(3/4).

23. Pickering Francis L. Competitive sports, disability, and problemsof justice in sports. J Philos Sport 2005;32(2):127Y132.

24. Howe PD. Cyborg and Supercrip: the Paralympics technologyand the (dis)empowerment of disabled athletes. Sociology 2011;45(5):868Y882.

25. Berger RJ. Disability and the dedicated wheelchair athletebeyond the ‘Supercrip’ critique. J Contemp Ethnogr 2008;37(6);647Y678.

26. Gilbert KD, Schantz OJ, Schantz O. The Paralympic Games:Empowerment or Side Show? Vol 1. Aachen, Germany: Meyer &Meyer Verlag; 2008.

27. Kell M, Price N, Kell P. Two games and one movement? TheParalympics and the Olympic movement. In: Learning and theLearner: Exploring Learning for New Times. New SouthWales, Australia: University of Wollongong; 2008:236.

28. Burkett B. Technology in Paralympic sport: performanceenhancement or essential for performance? Br J Sports Med2010;44(3):215Y220.

29. Burkett B. Paralympic sports medicineVcurrent evidence inwinter sport: considerations in the development of equipmentstandards for paralympic athletes. Clin J Sport Med 22(1):46Y50.

30. Magdalinski T. Enhancing the body from without: artificial skinsand other prosthetics. Routledge Online Studies on the Olympicand Paralympic Games 2012;1(37):109Y127.

31. International Paralympic Committee. Available at: http://www.paralympic.org. Accessed July 8, 2013.

32. DiGiovine CP, Koontz AM, Boninger ML. Advances in manualwheelchair technology. Top Spinal Cord Inj Rehabil 2006;11(4);1Y14.

33. Mortenson WB, Miller WC, Auger C. Issues for the selection ofwheelchair-specific activity and participation outcome measures:a review. Arch Phys Med Rehabil 2008;89(6):1177Y1186.

34. van der Woude LHV, de Groot S, Janssen TWJ. Manualwheelchairs: research and innovation in rehabilitation, sports,daily life and health. Med Eng Phys 2006;28(9):905Y915.

35. Cooper RA, Cooper R, Boninger ML. Trends and issues inwheelchair technologies. Assist Technol 2008;20(2):61Y72.

36. Goosey-Tolfrey V. Wheelchair Sport: A Complete Guide forAthletes, Coaches, and Teachers. Champaign, IL: HumanKinetics, 2010.

37. Costa GB, Rubio MP, Belloch SL, Soriano PP. Case study: effectof handrim diameter on performance in a paralympic wheelchairathlete. Adapt Phys Act Q 2009;26(4):352Y363.

38. Fuss FK. Influence of mass on the speed of wheelchair racing.Sports Eng 2009;12(1): 41Y53.

39. Siebert M. Adjustable handbike-chassis for offroad-use (‘Mountainhandbike’). Procedia Eng. 2010;2(2):3157Y3162.

40. Wucherpfennig FD, Boyer DJ. Personal mobility vehicleincorporating tilting and swiveling seat and method for usewhile playing golf. 2003001968430-Jan-2003.

41. Faupin A, Campillo P, Weissland T, et al. The effects of rear-wheelcamber on the mechanical parameters produced during thewheelchair sprinting of handibasketball athletes. J Rehabil ResDev 2004;41(3B):421Y428.

42. Burton M, Subic A, Mazur M, Leary M. Systematic designcustomization of sport wheelchairs using the taguchi method.Procedia Eng 2010;2(2):2659Y2665.

43. Berger MAM, van Nieuwenhuizen M, van der Ent M, van derZande M. Development of a new wheelchair for wheelchairbasketball players in the Netherlands. Procedia Eng 2012;34:331Y336.

44. Lei L, Guan TM, Tao Y. Design and analysis of the table tenniswheelchair based on the human engineering. Adv Mater Res2011;308Y310:2388Y2392.

45. Authier EL, Pearlman J, Allegretti AL, et al. A sports wheelchairfor low-income countries. Disabil Rehabil 2007;29(11Y12):963Y967.

46. Goosey-Tolfrey VL, Alfano H, Fowler N. The influence of cranklength and cadence on mechanical efficiency in hand cycling.Eur J Appl Physiol 2008;102(2):189Y194.

47. Kramer C, Schneider G, Bohm H, et al. Effect of differenthandgrip angles on work distribution during hand cycling atsubmaximal power levels. Ergonomics 2009;52(10):1276Y1286.

48. Kramer C, Hilker L, Bohm H. Influence of crank length andcrank width on maximal hand cycling power and cadence.Eur J Appl Physiol 2009;106(5):749Y757.

49. Arnet U, van Drongelen S, Schlussel M, et al. The effect ofcrank position and backrest inclination on shoulder load andmechanical efficiency during handcycling. Scand J Med SciSports 2012;24(2):386Y394.

50. Luc H, Van Der Woude V, Bosmans I. Handcycling: differentmodes and gear ratios. J Med Eng Technol 2000;24(6):242Y249.

51. van Drongelen S, van den Berg J, Arnet U, et al. Development andvalidity of an instrumented handbike: initial results of propulsionkinetics. Med Eng Phys 2011;33(9);1167Y1173.

52. Perk H. Upright wheelchair. 789169522-Feb-2011.

53. Marcellini A, Ferez S, Issanchou D, et al. Challenging humanand sporting boundaries: the case of Oscar Pistorius. PerformEnhanc Health 2012;1(1):3Y9.

54. Kram R, Grabowski AM, McGowan CP, et al. Counterpoint:artificial legs do not make artificially fast running speedspossible. J Appl Physiol 2010;108(4):1012Y1014.

55. Jones C, Wilson C. Defining advantage and athletic performance:the case of Oscar Pistorius. Eur J Sport Sci 2009;9(2):125Y131.


Volume 26 & Number 3 & 2014 163


http://www.paralympic.org

http://www.paralympic.org

56. Camporesi S. Oscar Pistorius, enhancement and post-humans.J Med Ethics 2008;34(9):639.

57. Lippi G, Mattiuzzi C. Pistorius ineligible for the Olympic Games:the right decision. Br J Sports Med 2008;42(3):160Y161.

58. Burkett B, McNamee M, Potthast W. Shifting boundariesin sports technology and disability: equal rights or unfairadvantage in the case of Oscar Pistorius? Disabil Soc 2011;26(5):643Y654.

59. Lechler K, Lilja M. Lower extremity leg amputation: anadvantage in running? Sports Technol 2008;1(4-5):229Y234.

60. Curran SA, Hirons R. Preparing our Paralympians: researchand development at Ossur, UK. Prosthet Orthot Int 2012;36(3):366Y369.

61. Brown MB, Millard-Stafford ML, Allison AR. Running-specificprostheses permit energy cost similar to nonamputees. MedSci Sports Exerc 2009;41(5):1080Y1087.

62. Buckley JG. Biomechanical adaptations of transtibial amputeesprinting in athletes using dedicated prostheses. Clin Biomech2000;15(5):352Y358.

63. Burkett B, Smeathers J, Barker T. Optimising the trans-femoralprosthetic alignment for running, by lowering the knee joint.Prosthet Orthot Int 2001;25(3):210Y219.

64. Madigan RR, Fillauer KD. 3-S prosthesis: a preliminary report.J Pediatr Orthop 1991;11(1):112Y117.

65. Tingleff H, Jensen L. Case report: a newly developed socketdesign for a knee disarticulation amputee who is an activeathlete. Prosthet Orthot Int 2002;26(1):72Y75.

66. Huff AM, Lawson BE, Goldfarb M. A running controller for apowered transfemoral prosthesis. In: 2012 Annual InternationalConference of the IEEE Engineering in Medicine and BiologySociety (EMBC). 2012:4168Y4171.

67. Nolan L, Patritti BL, Simpson KJ. A biomechanical analysis ofthe long-jump technique of elite female amputee athletes. MedSci Sports Exerc 2006;38(10):1829Y1835.

68. Nolan L, Patritti BL, Simpson KJ. Effect of take-off fromprosthetic versus intact limb on transtibial amputee long jumptechnique. Prosthet Orthot Int 2012;36(3):297Y305.

69. Nolan L, Patritti BL, Stana L, Tweedy SM. Is increased residualshank length a competitive advantage for elite transtibial amputeelong jumpers? Adapt Phys Act Q 2011;28(3):267Y276.

70. Schoeman M, Diss CE, Strike SC. Kinetic and kinematiccompensations in amputee vertical jumping. J Appl Biomech2012;28(4):438Y447.

71. Strike SC, Diss C. The biomechanics of one-footed vertical jumpperformance in unilateral trans-tibial amputees. Prosthet OrthotInt 2005;29(1):39Y51.

72. Nolan L, Lees A. The influence of lower limb amputation level onthe approach in the amputee long jump. J Sports Sci 2007;25(4):393Y401.

73. Nolan L, Patritti BL. The take-off phase in transtibial amputeehigh jump. Prosthet Orthot Int 2008;32(2):160Y171.

74. Nolan L, Lees A. Touch-down and take-off characteristics of thelong jump performance of world level above- and below-kneeamputee athletes. Ergonomics 2000;43(10):1637Y1650.

75. Frossard L, O’Riordan A, Goodman S. Throwing frame andperformance of elite male seated shot-putters. Sports Technol2010;3(2):88Y101.

76. Tweedy SM, Connick MJ, Burkett B, et al. What throwing frameconfiguration should be used to investigate the impact ofdifferent impairment types on Paralympic seated throwing?Sports Technol 2012;5(1Y2):56Y64.

77. Grindle GG, Deluigi AJ, Laferrier JZ, Cooper RA. Evaluation ofhighly adjustable throwing chair for people with disabilities.Assist Technol 2012;24(4):240Y245.

78. Fast JB. Fishing rod holder. 504410903-Sep-1991.

79. Krouth CW, Krouth GH. Fishing rod holder. 595688328-Sep-1999.

80. Richardson JO. Fishing rod holder. 600374621-Dec-1999.

81. Staelens D, Staelens M. Self casting remote control fishing rod.2005010891926-May-2005.

82. Johnson VW. Fishing rod casting device for a disabled person.443994403-Apr-1984.

83. Shelton BR. Fishing rod controller. 614189807-Nov-2000.

84. Byrd C. Fishing device for the disabled. 788647815-Feb-2011.

85. McCormick DP. Handicapped skiing: a current review ofdownhill snow skiing for the disabled. In: Bernhardt DB, Ed.Recreation for the Disabled Child. Vol 4. UK: PsychologyPress; 1985:27Y44.

86. Laskowski ER. Snow skiing for the physically disabled. MayoClin Proc 1991;66(2):160Y172.

87. Levesque C, Gauthier-Gagnon C. An improved downhill skiingprosthesis. J Prosthet Orthot 1989;1(2):104Y109.

88. Farley R, Mitchell F, Griffiths M. Custom skiing and trekkingadaptations for a trans-tibial and trans-radial quadrilateralamputee. Prosthet Orthot Int 2004;28(1):60Y63.

89. Demsar I, SupejM, Vidrih Z,Duhovnik J. Development of prostheticknee for alpine skiing. J Mech Eng 2011;57(10):768Y777.

90. Cavacece M, Smarrini F, Valentini PP, Vita L. Kinematic anddynamic analysis of a sit-ski to improve vibrational comfort.Sports Eng 2005;8(1):13Y25.

91. Langelier E, Martel S, Millot A, et al. A sit-ski design aimedat controlling centre of mass and inertia. J Sports Sci 2013;31(10):1064Y1073.

92. MinnoyeSLM,PlettenburgDH.Design, fabrication, andpreliminaryresults of a novel below-knee prosthesis for snowboarding: a casereport. Prosthet Orthot Int 2009;33(3):272Y283.

93. St-Jean C, Goyette C. Observations of ice-skating prosthesesdeveloped for a 7-year-OM transtibial amputee. J ProsthetOrthot 1996;8(1):21Y23.

94. Saadah ESM. Swimming devices for below-knee amputees.Prosthet Orthot Int 1992;16(2):140Y141.

95. Colombo C, Marchesin EG, Vergani L, et al. Design of an ankleprosthesis for swimming and walking. Procedia Eng 2011;10:3503Y3509.

96. Yoneyama K, Nakashima M. Development of swimmingprosthetic for physically disabled (optimal design for one sideof above-elbow amputation). In Moritz EF, Haake S, Eds. TheEngineering of Sport 6. New York, NY: Springer; 2006:431Y436.


164 Volume 26 & Number 3 & 2014


97. Zeller J. Canoeing and Kayaking for People With Disabilities.Champaign, IL: Human Kinetics, 2009.

98. Highsmith MJ, Carey SL, Koelsch KW, et al. Kinematicevaluation of terminal devices for kayaking with upper extremityamputation. J Prosthet Orthot 2007;19(3):84Y90.

99. Smoljanovi( T, Bojani( I, Morrison J, et al. Adaptive rowingVrowing or sculling for rowers with a disability. Hrvat SportVjesn 2008;23(2):59Y65.

100. World rowing. Available at: http://www.worldrowing.com/.Accessed July 29, 2013.

101. Dollar AM, Herr H. Design of a quasi-passive knee exo-skeleton to assist running. In: IEEE/RSJ International Con-ference on Intelligent Robots and Systems. 2008:747Y754.

102. Grabowski AM, Herr HM. Leg exoskeleton reduces the metaboliccost of human hopping. J Appl Physiol 2009;107(3):670Y678.


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http://www.worldrowing.com/

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