admoss_msc_0803_small_file _size

Velocometer: a telemetry-based device to measure intra-push changes in racing
wheelchair velocity
Andrew D. Moss
A thesis submitted in partial fulfilment of the requirements of the Manchester
Metropolitan University for the degree of Master of Science by Research
Department of Exercise and Sport Science
Crewe+Alsager Faculty
Manchester Metropolitan University
August 2003
I certify that all material in this thesis that is not my own work has been identified
and that no material is included for which a degree has previously been conferred
upon me

ii
Abstract
Measurement of the intra-push changes that occur in racing wheelchair velocity is
important because it assists in explaining how wheelchair athletes accelerate their
wheelchairs. This information has direct application to training and coaching in
wheelchair athletics. The purpose of this thesis is to present the design, functional
characteristics and utility of a telemetry-based velocometer with the ability to
measure intra-push changes in racing wheelchair velocity.
Studies one to five describe the functional characteristics of the velocometer.
Validity and system linearity: a linear relationship was found when velocity
calculated from the velocometer was plotted against three test velocities. The average
root mean square deviation (ARMSD) was used to compare velocity calculated from
the velocometer with velocity calculated by manual digitising. The ARMSD
calculated for each test speed from three trials was 0.06 ± 0.002, 0.27 ± 0.05 and 0.48
± 0.16 m.s-1
at 1, 5 and 9 m.s-1
respectively. Dynamic response: the ARMSD
calculated from the five acceleration and five deceleration trials was 0.29 ± 0.086
and 0.51 ± 0.115 m.s-1
respectively. Reliability: the ARMSD was used to compare
the mean trial velocity calculated from velocometer and the speed of the wheelchair
rear wheels spun using a DC servomotor. The mean and standard deviation of the
differences were 0.079 ± 0.008 m.s-1
, for the eight disc-wheel trials and -0.014 ±
0.019 m.s-1
, for the eight spoke-wheel trials. Resistance: velocometer resistance
calculated as a factor of the mechanical resistance of the wheelchair rear wheel
spinning in air was 0.50 and 0.91 N, for the disc and spoke wheel trials respectively.
Velocometer resistance calculated as a factor of the total mechanical resistance of the
wheelchair/wheelchair-user system was 1.37 and 1.82 N, for the disc and spoke
wheel trial respectively.
The purpose of the sixth study was to use the velocometer in the analysis of the first
six pushes of a sprint start in over-ground racing wheelchair propulsion. One
experienced international male wheelchair athlete (age = 28 years; body mass = 60.6
kg; racing classification = T4) performed ten maximal over-ground sprint start trials,
over approximately 10 m, in his own racing wheelchair fitted with a Velocometer.
Each trial was filmed at 200 Hz using a “Pan and Tilt” system. Eight trials were
manually digitised at 100 Hz. The raw co-ordinate data were smoothed using a
quintic spline routine. The duration of each push cycle decreased from 0.82 ± 0.02 to
0.45 ± 0.01 s. Within each push the mean duration of the propulsive phase decreased
from 0.62 ± 0.02 to 0.21 ± 0.01 s. The mean duration of the recovery phase increased
from 0.20 ± 0.01 to 0.24 ± 0.02 s. The athlete contacted the rim progressively closer
to top dead centre with each push. Similarly, the athlete released the rim
progressively closer to bottom dead centre with each push. The data indicate that
peak velocity occurs after release. This is due to the motion of the trunk.
The main findings of this study support the observation that racing wheelchair
propulsion is a complex form of locomotion and cannot be described accurately by
using just the established definitions of a propulsive and a recovery phase. The
velocometer provides an effective research tool for the measurement of intra-push
changes in velocity, which can be used to further the body of knowledge with regard
to racing wheelchair propulsion.

iii
Acknowledgements
My sincere thanks go to my supervisors, Dr Neil Fowler and Dr Vicky Tolfrey. They
have been helpful, supportive, encouraging throughout the duration of this M.Sc.
Neil, you have an amazing ability to explain clearly, and with some obvious
excitement, the most complicated biomechanical concepts. Vicky, your guidance
during my involvement with the British Wheelchair Racing Association (BWRA)
sport science support project, gave me an invaluable grounding in applied work on
which the foundations of this M.Sc thesis are based. I would also like to sincerely
thank Tom McKee for his vast knowledge and expertise in the field of electronics,
hard work and enthusiasm.
I would like to gratefully acknowledge Draft wheelchairs for allowing me the use of
a state of the art racing wheelchair and Edward Grazier for trusting me with his
carbon fibre wheels. As a cyclist I know how valuable these things are.
I am indebted to the individuals who gladly gave up their time for my studies. To
Tanni Grey-Thompson and Chris Hallam, my thanks are for educating me in all
things wheelchair racing. I wish all of you the best in your future racing.
I consider myself fortunate to have good friends. To Mark Johnson, Jason Martin and
Ellen Dawson. I offer my sincere thanks for their friendship, support and advice over
the last seven years.
Above all, I would really like to thank my mum for more things than I can possibly
list here, but mainly her love and kindness.

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Publications
The following parts of this thesis have been published or are under review for
publication.
Publication
Moss, A. D., Fowler, N. E., Tolfrey, V. L. (2003). A telemetry-based velocometer to
measure wheelchair velocity. Journal of Biomechanics, 36 (2), 253 – 257.
Under Review
Moss, A. D., Fowler, N. E., Tolfrey, V. L. An explanation of the intra-push velocity
profile of over-ground racing wheelchair propulsion during the first six pushes of the
sprint start.

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List of contents
Contents Page
Title Page i
Abstract ii
Acknowledgements iii
Publications iv
List of contents v
List of tables ix
List of figures x
Glossary of abbreviations xii
Glossary of terms xiv
1. Chapter 1 16
1.1. Introduction 16
1.1.1. Wheelchair sports and the Paralympic Games 16
1.1.2. British Paralympic success 16
1.1.3. Wheelchair sprinting: Technical background 17
1.1.4. A deterministic model for wheelchair sprinting 18
1.1.5. Summary 21
1.1.6. Aim 21
1.1.7. Objectives 22
1.1.8. Hypothesis 22
1.2. Literature review 23

vi
1.2.1. Inclusion criteria 23
1.2.2. Wheelchair related research 24
1.2.3. Wheelchair racing: development of a sport 25
1.2.4. Ergonomics 26
1.2.4.1. Wheelchair-user interface: seat 28
1.2.4.2. Wheelchair-user interface: push-rim 29
1.2.4.3. Manual wheelchair propulsion daily use vs. sport 31
1.2.5. Assessment of athletic wheelchair performance 31
1.2.5.1. Simulated wheelchair propulsion under realistic 32
Conditions
1.2.5.1.1. Wheelchair ergometers (WERGs) 34
1.2.5.1.2. Motor driven treadmills (MDTs) 36
1.2.5.1.3. Over-ground manual wheelchair propulsion 37
1.2.5.1.4. Protocols 56
1.2.5.1.5. Physiological assessment of the wheelchair 61
Athlete
1.2.5.1.6. Biomechanical assessment of the wheelchair 61
1.2.6. Summary 75
2. Chapter 2 77
2.1. A telemetry-based velocometer to measure wheelchair velocity 77
2.1.1. Design of the device 78
2.1.2. Sampling 81
2.1.3. Mounting 81
2.1.4. Calibration 81

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2.2. Study 1: validity and system linearity 83
2.2.1. Introduction 83
2.2.2. Method 84
2.2.3. Results 86
2.2.4. Discussion 88
2.3. Study 2: dynamic response 91
2.3.2. Method 92
2.3.3. Results 94
2.4. Study 3: reliability 96
2.4.2. Method 97
2.4.3. Results 98
2.5. Studies 4 and 5: resistance 102
2.5.2. Method 103
2.5.3. Results 106
3. Chapter 3 110
3.1. Study 6: an explanation of the intra-push velocity profile of 110
over-ground racing wheelchair propulsion during the first six
pushes of the sprint start

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3.1.2. Method 111
3.1.2.1. Calibration 114
3.1.2.2. Pilot study 116
3.1.2.3. Data collection 119
3.1.2.4. Data analysis 121
3.1.2.5. Digitising error 123
3.1.3. Results 123
3.1.3.1. Coefficient of variation 131
3.1.3.2. Relative momentum analysis 131
3.1.5. Conclusion 139
4. Chapter 4 141
4.1. General Discussion 141
4.1.1. Limitations 143
4.2. Conclusion 145
4.3. Future Recommendations 145
References 147
Appendices 174

ix
List of tables
Table Title Page
Table 1 Wheelchair coding for tables 2, 3 and 4 39
Table 2 Studies using a wheelchair ergometer to simulate
manual wheelchair propulsion
40
Table 3 Studies using a motor driven treadmill to
simulate manual wheelchair propulsion
51
Table 4 Studies employing over-ground manual
wheelchair propulsion
54
Table 5 Velocometer resistance calculated from rundown
trials
107
Table 6 Actual and calculated pan and tilt calibration
values
114
Table 7 Mean propulsive cycle data for the first six
pushes of the sprint start calculated from eight
trials
124
Table 8 Mean velocity data for the first six pushes of the
sprint start calculated from eight trials
126
Table 9 Mean acceleration data for the first six pushes of
the sprint start calculated from eight trials
127

x
List of figures
Figure Title Page
Figure 1 A deterministic model for wheelchair sprinting 20
Figure 2 Optical encoder and transmitter assembly 79
Figure 3 Telemetry system block diagram 80
Figure 4 Calibration equation 82
Figure 5 Experimental set-up for studies 1, 2, 3 and 4
showing treadmill wheelchair mounting system
(TWMS)
85
Figure 6 Velocometer validity and system linearity 87
Figure 7 Wheelchair and velocometer wheel dimensions 90
Figure 8 Velocometer and manually digitised, 2D video
film data collected during (a) one acceleration
trial and (b) one deceleration trial
93
Figure 9 Agreement between the constant velocity of a
wheel spinning in air and mean velocity
calculated from the velocometer data, within a
five percent error band, from (a) Ten disc wheel
trials (b) Ten spoke wheel trials
99
Figure 10 Study 5 experimental set-up showing camera and
calibration pole placement in relation to the line
of progression
105

xi
Figure 11 Study 6 experimental set-up showing the pan and
tilt camera and calibration pole placement in
relation to the line of progression
113
Figure 12 Calibration procedure. Point denoted by cross is
digitised as follows: 1) Top point at bottom of
view, 2) Top point at top of view, 3) Bottom
point at bottom of view, 4) Bottom point at top of
view
115
Figure 13 Upper extremity calibration frame 118
Figure 14 Wheelchair/wheelchair-user system model used
in the manual digitising of the 3D video film
121
Figure 15 Intra-push wheelchair velocity and trunk,
shoulder and elbow angular displacement during
the first six pushes of the sprint start
129
Figure 16 Intra-push wheelchair velocity and trunk,
shoulder and elbow angular velocity during the
first six pushes of the sprint start
130
Figure 17 The relationship between relative, transfer and
total momentum of the head and trunk during the
first six pushes of the sprint start
132

xii
Glossary of abbreviations
Abbreviation Clarification
ISMGF International Stoke Mandeville Games Federation
NWAA National Wheelchair Athletic Association
BPAA British Paraplegics Athletics Association
IOC International Olympic Committee
MDT Motor Driven Treadmill
WERG Wheelchair Ergometer
HAT Head, Arms and Trunk
SCI Spinal Cord Injury
CP Cerebral Palsy
SB Spina Bifida
AB Able Bodied
BSEN British Standard European Standards
ARMSD Average root mean square deviation
TDC Top Dead Centre
BDC Bottom Dead Centre
WAnT Wingate Anaerobic Test
P5 Highest mean power output from any five second period during
(WAnT)
P30 Mean power output measured during 30 second (WAnT)
IOF Index of Fatigue
Fiso Isometric Strength

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HR Heart Rate
VE Ventilation rate
MTT Montreal progressive Tack Test
Vc Critical velocity test
Vch Maximal velocity with lactate steady state test
RPE Rating of Perceived Exertion
HLa Blood lactate
2OV! Oxygen Uptake
2OV! Peak Peak Oxygen Uptake
POaer Maximal Aerobic Power Output
ME Mechanical Efficiency

xiv
Glossary of terms
Term Clarification
Quadriplegia. Condition resulting from SCI at the level of the cervical
vertebrae
Paraplegia Condition resulting from SCI at the level of the thoracic
vertebrae or below
Wheelchair /wheelchair
user system
Wheelchair and wheelchair user as one integrated unit
Wheelchair/wheelchair-
user interface
The point of integration between the wheelchair and the
wheelchair user e.g. Seat cage, push-rim and gloves
Manual wheelchair
propulsion
The act of locomotion in a push-rim wheelchair
Propulsive cycle The movements that bring about locomotion from hand
contact to subsequent hand contact at the start of the next
propulsive cycle
“propulsive” or “push”
phase
The period between the instant of hand contact to the
instant of release while the hand is in contact with the
push-rim
“non-propulsive” or
“recovery” phase
The period between the instant of release to the instant of
contact while the hand is not in contact with the push-rim
Total momentum The combined contribution of all body segments to
momentum of the system
Relative momentum The contribution of a particular body segment to the total

xv
momentum of the system
Transfer momentum The momentum that is transferred to a particular body
segment from the proximal segment

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1. Chapter 1
1.1. Introduction
1.1.1. Wheelchair Sports and the Paralympic Games
Wheelchair sports were originally developed shortly after World War II by Sir
Ludwig Guttman and colleagues as a rehabilitation tool, a means to provide exercise
and recreation for young persons injured during the war. By 1952 the games had
developed into the first international wheelchair sporting competition for the
disabled. In the same year the International Stoke Mandeville Games Federation
(ISMGF) was formed to develop and govern wheelchair sports. The ISMGF later
established ties with the International Olympic Committee (IOC) and in 1960 the
first international games for the disabled held in conjunction with the Olympic
Games took place in Rome. During the 1964 Tokyo games the name “Paralympics”
was coined. Subsequently, the Paralympic Games have been held every four years.
1.1.2. British Paralympic success
Of all the 18 Paralympic sports wheelchair racing is arguably the most high profile
and, like mainstream athletics, sprint events take centre stage. Wheelchair sprinting
(events from 100 to 800 m) is also where Britain achieves most of its success in
international competition. British wheelchair athletes returned from the 1996
Paralympic Games in Atlanta, USA with nine medals. Two gold medals and new

17
World records (Tanni Grey, 800m, time: 1.55.12 mins and David Holding, 100 m,
time: 14.45 s), three silver medals (Tanni Grey, 100 m, 200 m and 400 m) and four
bronze medals (Nicola Jarvis, 100 m and 200 m, Paul Williams, 100 m and David
Holding 200 m). The success of British wheelchair athletes was shown to the world
thanks to the extensive media coverage of the 2000 Olympic and Paralympic Games
in Sydney, Australia. In the Paralympic Games British athletes finished second in the
medal table, only surpassed by the host nation. Great Britain’s athletes officially
became Britain’s most successful Paralympic Team ever. British wheelchair athletes
returned with seven medals. Five gold medals (Tanni Grey – Thompson 100 m, 200
m, 400 m and 800 m and Deborah Brennan 200 m) and Two bronze medals
(Deborah Brennan 200 m and David Holding 100 m). In addition Deborah Brennan
set a new World record over 200 m with a time of 33.87 s.
1.1.3. Wheelchair sprinting: Technical background
The goal of the wheelchair sprinter is the same as that of the sprint runner, which is
to cover the race distance in the shortest possible time. For the runner the race is
made up of a number of strides. Each stride can be broken down further into two
basic components, stride length and stride frequency. The same is true for the
wheelchair athlete, the race consists of a number of propulsive cycles consisting of a
push phase and a recovery phase. The push phase begins at the point of hand contact
with the push-rim. During the push phase the propulsive impulse that brings about
forward motion is imparted from the body to the push-rim. The recovery phase
begins at the point at which the hand releases the push-rim. The movements that

18
return the body to the point immediately before hand contact combine to make up the
recovery phase. The push phase can be broken down into pushing length (the
distance covered by the wheelchair with each push on the push-rim) and pushing
frequency (the number of pushes per unit of time). Walsh (1986) states wheelchair
velocity can only be increased through manipulation of one or both of these factors.
1.1.4. A deterministic model for wheelchair sprinting
The deterministic model for wheelchair sprinting (figure 1) identifies the key
components that determine the success of a wheelchair sprint athlete. As stated
previously the goal of the wheelchair sprinter is to cover the race distance in the
shortest possible time, therefore, the goal of the wheelchair sprinter is the
development of speed.
With the use of sophisticated laboratory based equipment sport scientists are able to
measure many of the components shown in figure 1 during simulated racing
wheelchair propulsion (RWP). Information relating to performance enhancement can
then be collated and disseminated to coaches and athletes. Unfortunately RWP
simulated in a laboratory environment is artificial compared to RWP in a competitive
environment (Vanlandewijck et al. 2001). RWP data collected in this artificial
environment provides a false description of RWP in a competitive environment and
therefore may not be directly applicable to enhance the performance of wheelchair
athletes. Scientists working to enhance the performance of wheelchair athletes must

19
develop methods of collecting data during over-ground RWP in competition in order
to gain an accurate picture of how wheelchair athletes propel their wheelchairs.

20
Figure 1 A deterministic model for wheelchair sprinting
Wheel Velocity
Point of Contact Point of Release
Contact Radius
Contact Time
Muscle Cross
Sectional Area
Activation Muscle Length
Total Muscle
Force
Point of Force
Application
Seating Position Joint Angles Segmental Lengths Pushrim Size
Segmental Motion
Direction
Direct Propulsion
Force
Relative Momentum
of Segments
Indirect Propulsion
Force
Propulsive Impulse
Speed
Resistive Impulse
Friction Rolling Resistance
Mechanical Resistance
Wheelchair Athlete
Frontal Surface Area Coefficient of Drag Segmental Density Velocity
Drag Non-contact Time

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1.1.5. Summary
The information above clearly identifies British wheelchair sprinting as being at the
forefront of international disability sport. However, at present the ability of the sport
scientist and coaches to further enhance the performances of these athletes is
hampered by methodological constraints. To ensure the continued success of British
wheelchair sprint athletes, equipment must be developed for the collection of data
during over-ground wheelchair sprinting.
A velocometer that could measure racing wheelchair velocity, would provide a
useful research tool in the study of propulsion technique. The device would allow the
velocity profile of the wheelchair to be constructed. The velocity profile would
provide information on the intra-push characteristics of propulsive cycle.
1.1.6. Aim
1. To design, produce and to test the utility of a velocometer to be used in the
assessment of intra-push changes in wheelchair velocity during over-ground
propulsion.

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1.1.7. Objectives
1. To assess the functional requirements of the velocometer in relation to best
practice for the collection of data from wheelchair athletes.
2. To manufacture the velocometer in accordance with the functional requirements
assessed in objective 1.
3. To test the velocometer in accordance with the functional requirements assessed
in objective 1 by using the device to record the velocity profile of a racing
wheelchair during a sprint trial.
1.1.8. Hypothesis
The velocometer provides an accurate and reliable method for quantifying intra-push
changes in racing wheelchair velocity during over-ground propulsion.

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1.2. Literature review
This literature review is intended to provide the reader with a summary of the
findings of selected wheelchair related research. The literature under review covers
the period from the mid 1970’s, when manual wheelchair propulsion first became the
subject of scientific investigation, through to the present. In Sydney 2000 the world
witnessed the most integrated and successful Paralympic Games to date. Wheelchair
sport is now considered to be at the forefront of disability sport.
1.2.1. Inclusion criteria
The research reviewed in this section has been subjected to inclusion criteria. The
criteria are intended to ensure only studies that do not suffer from the major
limitations inherent in wheelchair related research are included. Preference has been
given to studies in which data has been collected from athletes, using their own
racing wheelchairs, during realistic simulated or actual over-ground manual
wheelchair propulsion. Where appropriate, only studies which have utilised over-
ground manual wheelchair propulsion or who have realistically simulated manual
wheelchair propulsion using a motor driven treadmill are included. Studies using
able-bodied subjects with little or no wheelchair experience have not been considered
for inclusion. Studies in which daily use, basketball or “active” wheelchairs,
interchanged between subjects, are also not included. Research findings related to
lever operated or hand crank wheelchairs has been excluded on the basis that manual

24
wheelchair propulsion is the most widely used method of locomotion for wheelchair
users.
1.2.2. Wheelchair related research
Previously the global aim of many researchers conducting wheelchair related
research has been to contribute to an improvement in the quality of life of lower limb
disabled persons who rely on wheelchairs for everyday mobility. However, many
researchers have used the growth and maturity of wheelchair sport as justification for
scientific investigation (Steadward and Walsh 1986). Cooper (1990c) states that in
recent years the progression of world records had slowed significantly, suggesting
that a point had been reached in terms of equipment and training at which small
differences become more significant. If continued improvements in wheelchair
racing are to be made, greater knowledge of the interaction between an individual
and their wheelchair will be required. To the sport scientist looking to enhance
performance the wheelchair/wheelchair-user system poses a similar problem to that
of any athlete whose interaction with a specific piece of equipment brings about a
sporting performance. Cooper (1996) states manual wheelchair research can be
divided into: design and testing; ergonomics and clinical assessment; physiology and
nutrition; and biomechanics.
For a comprehensive collection of wheelchair related research papers the reader is
directed to two published works edited by Woude et al. (1993) and Woude et al.
(1999). These compilations of wheelchair related research papers, based on the

25
proceedings of international workshops, show the variety and direction of wheelchair
related research in 1991 and 1999.
1.2.3. Wheelchair racing: development of a sport
In possibly the first study specifically targeting wheelchair racing, Higgs (1983)
characterised racing wheelchair construction in terms of success at the 1980 Olympic
games for the disabled. He found that the wheelchairs of more successful athletes
were characterised by lower seats, an increased seat angle to the horizontal, narrower
frame and smaller push-rims. In relative comparison the chairs used by the successful
sprinters had higher and more forward placed seats and a shorter chair length. No
significant differences in rear wheel camber were found.
Hedrich et al. (1990) provides an excellent description of the developments in
wheelchair racing between 1970 and 1990. Prior to the mid 1970s, wheelchair racing
existed as an accelerated version of conventional wheelchair propulsion mechanics.
The same wheelchairs used in everyday pursuits were used for sport (LaMere and
Labanowich 1984a). Recent advancements in wheelchair technology and training
have improved performance. However, the propulsion mechanics of wheelchair
racing have been dramatically altered (Higgs 1986; LaMere and Labanowich 1984a,
1984b, Sanderson and Sommer 1985, Steadward and Walsh 1986). Contemporary
wheelchair frames and wheels are built of aircraft quality alloys that are lighter and
stronger than steel or aluminium. Sealed precision bearings are now used in order to

26
reduce mechanical friction and in order to reduce rolling resistance, bicycle racing
wheels with narrow profiles and high pressure racing tyres are used.
To some degree the aerodynamic properties of the racer and the wheelchair have also
been addressed. Similar to cycling many wheelchair racers wear skin tight,
lightweight clothing to minimise aerodynamic drag. Athletes have chosen to reduce
the number of rear wheel spokes, adopt radial rather than crossing spoke patterns and
use flat rather than round spokes. These wheel modifications enhance the
aerodynamic properties of the racing wheelchair. Many athletes have adopted a
seating position with flexed upper trunk. Originally adopted because it assured upper
torso stability while concurrently allowing more severely disabled racers to push as
efficiently as their less disabled counterparts, athletes now believe that adopting this
position improves their propulsive efficiency and reduces drag.
1.2.4. Ergonomics
Woude et al. (1989a) described ergonomics as the “optimisation of human work”.
The ergonomic approach to the study of manual wheelchair propulsion seeks to
optimise the wheelchair-user interface, the fit between the wheelchair user and the
wheelchair itself. Cooper (1990c) states the seat cage and the push-rims are two of
the most critical interfaces between the individual and his/her racing wheelchair. The
seat cage provides support and stabilisation and determines body position with
respect to the push-rims. The efficiency of the force transference is dependent upon
the limb geometry with respect to the push-rim. The characteristics of the seat can be

27
broken down into position (in relation to the rear wheel axel and therefore the push-
rims, and height from the ground) and construction (upholstery). Seating can be
further broken down in terms of the angle of the base from the horizontal and height
of the backrest. Push-rims vary in the overall diameter, the diameter of the tubing
used in there construction, the distance they are mounted from the surface of the rear
wheels and the material covering the outer surface. These considerations have
obvious implications for the design of performance wheelchairs. In the design of
performance wheelchairs not only is the optimisation of the wheelchair-user
interface, maximising the ability of the athlete, a prime consideration but also the
performance characteristics of the wheelchair. Rolling resistance, internal friction
and aerodynamic drag must all be considered.
For most wheelchair athletes seating is highly individual. In most modern racing
wheelchairs the seat may be only a few pieces of strategically placed upholstery
strapped to the frame of the wheelchair. Similarly, the sizes of the push-rims are also
highly individual. Wheelchair athletes use push-rims that are of a smaller overall
diameter than those typically seen on “daily use” or “active” wheelchairs. The reason
is speed. Wheelchair athletes need to be able to accelerate their wheelchairs quickly
to top speed and then continue to propel them at a high percentage of that top speed
for the duration of the event. The size of the push-rim can be likened to the gearing
on a bicycle. The smaller the gear, the faster the bicycle will travel at any given
cadence.

28
1.2.4.1. Wheelchair-user interface: seat
The relationship between seat position and the biomechanics of manual wheelchair
propulsion has received great attention (Hughes et al., 1992, Mâsse et al., 1992,
Ruggles et al., 1994). Unfortunately a general lack of standardisation means that the
results of these studies are difficult to compare and generalise to other groups. It is
particularly difficult to infer useful information that can be applied to wheelchair
sprint athletes. Walsh et al. (1986) investigated the effect of seat position on maximal
linear velocity in wheelchair sprinting. The study utilised an adjustable wheelchair
fixed to a WERG to assess the effects of nine different seating positions believed to
cover the range of seating positions used by wheelchair athletes. The study found no
significant differences between the maximal linear velocities measured for each of
the nine seat positions. Meijs et al. (1989) investigated the effect of seat height on the
physiological response and propulsion technique in wheelchair propulsion. Meijs et
al. (1989) took into account the anthropometric dimensions of the nine male non-
wheelchair users in order to obtain better standardisation across trials. The study
found that seat height has a significant effect on physical load and propulsion
technique. The paper states that the reason some authors (Brattgård et al., 1970,
Brubaker et al., 1981, 1984) found no difference may have been due to the non-
standardisation of power output and seat height adjustment to individual’s
anthropometrical dimensions. Meijs et al. (1989) concluded the range in which the
wheelchair seat can be adjusted should cover an elbow angle of 100 to 120 °. The
author also states that the results may underline the importance of adjusting
wheelchair dimensions to the anthropometric characteristics of the user. These results
are similar to a previous study conducted by Woude et al. (1989a). Woude et al.

29
(1989a) indicated that, based on comparative physiological responses to propulsion,
the optimum angle of elbow flexion, is between 100 and 120 °. To date no studies
have successfully identified an optimal seating position for wheelchair sprint
athletes.
1.2.4.2. Wheelchair-user interface: push-rim
Gayle et al. (1990a) investigated the effect of two different sized push-rims (0.25 and
0.41 m overall diameter) on cardiorespiratory and perceptual responses to wheelchair
propulsion. Fifteen male paraplegics (3 track athletes, 12 recreational athletes)
performed three discontinuous laboratory based exercise tests and two 1600 m
performance based track trials. A racing wheelchair (Stainless Medical Products
Racer, San Diego, CA), modified for use with each subject, was used for the entire
series of laboratory and track based trials. The results reported no significant
differences in HR, 2OV! , VE, HLa or RPE using different sized push-rims at 4 km.h-1
.
At 8 km.h-1
subjects demonstrated a 13 % lower steady state 2OV! (p<0.05) using the
0.25 m push-rims. HR was not significantly different. Under simulated race
conditions on an all weather track no significant differences were found for HR,
performance time, or RPE between trials. HLa was significantly lower using the 0.25
m push-rims. The authors concluded that although the data identified few significant
differences in the physiological responses between trials, there was a tendency for a
lower metabolic stress using the smaller push-rims.

30
Woude et al. (1988b) investigated the effects of five different diameter (0.3, 0.35,
0.38, 0.47 and 0.56 m) push-rims and varying speeds on a number of physiological
and kinematic variables. Eight wheelchair sportsmen (6 SCI [T2-LS], 1 Spina Bifida,
1 AB) used similar racing wheelchairs (weights ranged from 11 to 13 kg, rear wheel
camber 8.5°, tyre pressure standardised). The push-rims used all had a similar grip
profile and were constructed of 0.03 m tubing taped with soft plastic. Five
progressive exercise tests were randomly spaced on three subsequent days. Each test
consisted of five 3 min stages on a MDT. Tests were performed with a constant
treadmill inclination of 0.5 °. Belt velocity was increased by 0.83 m.s-1
every three
minutes. Speed ranged from 0.83 to 4.17 m.s-1
.
The authors conclude, in terms of 2OV! , VE, HR, and gross ME; a smaller diameter
push-rim is more advantageous during high-speed wheelchair propulsion. Despite
inter-individual variation in movement technique and timing pattern, general patterns
of adaptation to rim diameter and wheelchair velocity were evident. Different push-
rim diameters were shown to lead to systematic shifts in the trajectories of the upper
arm, whereas no changes in timing parameters, push angle, and work per cycle were
seen. These findings may explain the increased cardiorespiratory stress observed at a
given velocity when using larger push-rims.
Based on a survey performed during the 1980 Olympics for the Disabled, Woude et
al. (1988b) stated that high level performance in wheelchair racing may be associated
with lower and more inclined seats, increased rear wheel camber, and smaller push-
rims. However, with the exception of Walsh et al. (1986), who reported the effect of
seat height on sprint performance, there is still a general lack of information

31
regarding optimum wheelchair-user interface characteristics for wheelchair sprint
athletes.
1.2.4.3. Manual wheelchair propulsion daily use vs. sport
Boninger et al. (1998) states that the nature of wheelchair propulsion means manual
wheelchair users are essentially walking with their arms. The upper extremity,
particularly the shoulder, is designed for freedom of movement and not repetitive
loading. Boninger et al. (1997) elaborated further. In order to propel a wheelchair a
force must be imparted to the push-rim. This force is analogous to the highly studied
ground reaction force of gait. The forces imparted to the push-rim are equally and
oppositely transmitted back to the upper limb of the wheelchair user. It is likely that
these joint reaction forces are responsible, in part, for a large majority of upper limb
injuries occurring in manual wheelchair users. Cooper (1990c) commented on the
increased demands of manual wheelchair propulsion in the sporting environment
compared to “daily use”. This seems logical when we consider the increased speed
and force requirements of accelerating a wheelchair and propelling a wheelchair at
high speed.
1.2.5. Assessment of athletic wheelchair performance
With the growth and maturity of wheelchair sport, practitioners began to train and
develop themselves in accordance with the general training principles of athletic

32
performance. The scientific community has taken an interest in wheelchair sports
persons. Equipment such as wheelchair ergometers (WERGS) were developed
(Glaser et al., 1978, Niesing et al., 1988, 1990, Vosse et al., 1990) and motor driven
treadmills (MDTs) were modified to accommodate wheelchairs (Horvat et al., 1984,
Claremont et al., 1985, Lakomy et al., 1987). Tables 2, 3 and 4 indicate the
prevalence of WERGs in relation to MDTs and over-ground manual wheelchair
propulsion in the manual wheelchair propulsion literature. Physiological testing
protocols were modified and tested with wheelchair users (Hartung et al., 1993,
Rasche et al., 1993, Goosey et al., 1995). The training practices of wheelchair
athletes were evaluated (Campbell et al., 1997) and investigated in relation to the
physiological characteristics of able-bodied athletes (Lakomy et al., 1987). The
laboratory based physiological testing of wheelchair athletes is now common.
However, Vanlandewijck et al. (2001) have called into question the realism of some
of the methods used to simulate manual wheelchair propulsion in the laboratory.
1.2.5.1. Simulated wheelchair propulsion under realistic conditions
The propulsive cycle has been the focus of many research studies. Like the running
stride the propulsive cycle has been broken down in terms of a contact, often termed
“propulsive”, and a non-contact, often termed “recovery”, phase. The contact phase
refers to the period between the instant the hand contacts the push-rim until the
instant the hand leaves the push-rim. The non-contact phase refers to the period
between the instant the hand leaves the push-rim until the instant before the hand
contacts the push-rim at the start of the next propulsive cycle.

33
These definitions have become standard terms in the manual wheelchair propulsion
literature. A wealth of research has been performed using these definitions.
Unfortunately this seems to have had the effect of simplifying manual wheelchair
propulsion research into an investigation purely of arm work, neglecting the
contribution of the head and trunk at a fundamental level. This is particularly
important in racing wheelchair propulsion in which the motion of the trunk and head
are exaggerated.
Vanlandewijck et al. (1994) provided an intra-push description of manual wheelchair
propulsion. The authors noted a twofold acceleration in the velocity curve of the
wheelchair-user system at 2.22 m.s-1
. Propulsive forces acting on the push-rims were
responsible for acceleration during the propulsive phase. During the recovery phase,
a second, smaller acceleration was observed. This second acceleration was due to
experienced subjects accelerating their trunk and/or arms backward causing reaction
forces to act on the wheelchair. These actions delayed deceleration of the wheelchair.
The above findings demonstrate that wheelchair propulsion at velocities typically
observed in wheelchair racing do not consist of an “active” period (the propulsive
phase) and a “passive” period (the recovery phase) as argued by Veeger et al.
(1992b). The author’s state that wheelchair propulsion in experienced wheelchair
racers consists of three periods, each of which has specific energy demands. 1) An
acceleration period which occurs due to the forces applied to the push-rims; 2) A
second, smaller, acceleration period due to inertial forces acting on the wheelchair-
user system. This is caused by the backward trunk and/or arm- swing described
above; and 3) A deceleration period due to resistive forces acting on the wheelchair-
user system, caused by an increased forward segmental velocity in order to make

34
contact with the rims with increased hand speed. Vanlandewijck et al. (2001)
provides a similar description stating that manual wheelchair propulsion consists of:
1) An acceleration phase caused by forces applied to the push-rims, 2) A second
acceleration phase caused by the inertial forces acting on the wheelchair-user system,
caused by a backward arm and/or trunk swing and 3) A deceleration phase during the
second part of the recovery phase.
1.2.5.1.1. Wheelchair ergometers (WERGs)
Wheelchair ergometers are commonplace in manual wheelchair propulsion research.
According to Glaser et al. (1977), Arabi et al. (1997) and Bhambhani et al. (1991),
the use of wheelchair ergometry in the study of the physiology of manual wheelchair
propulsion with paraplegic and quadriplegic subjects is reliable and valid. Arabi et
al. (1997) examined the relationship between maximal oxygen uptake on a MDT and
WERG and concluded that the data obtained were similar and significantly correlated
when expressed in either l.min-1
or ml.kg.min-1
(1.25 ± 0.38 and 1.22 ± 0.28 l.min-1
or 19.5 ± 6.14 and 18.18 ± 4.27 ml.kg.min-1
) for MDT and WERG respectively.
However, significant differences were found in maximal speed between the MDT
and WERG. This was probably due to the mechanical resistance of the rollers used in
the construction of the WERG. Bhambhani et al. (1994) performed a comparison
between simulated wheelchair racing on a WERG and track racing. The study
concluded that simulated wheelchair racing on a WERG is a valid measure of track
racing performance in male paraplegic and quadriplegic athletes. Generally speaking

35
the use of WERGs for physiological assessment is acceptable as the device is
bringing about a physiological response to a given workload.
Tables 2, 3 and 4 provide the reader with a comparison between studies that have
chosen to use WERGs, MDTs or over-ground manual wheelchair propulsion during
data collection. Table 1 provides the key to the wheelchair coding used in tables 2, 3
and 4 The main advantage of WERGs are that they can be used to simulate manual
wheelchair propulsion in a controlled laboratory environment. The laboratory
environment affords the researcher far greater opportunity for measurement,
unfortunately this is at the cost of realism. Wheelchair ergometers exist in two
common forms. 1) WERGs constructed as an approximation of a wheelchair with the
wheels and the seat mounted separately (Niesing et al., 1988, 1990, Vosse et al.,
1990). 2) WERGs incorporating either single (Goosey et al., 1998a) or twin
(Shimada et al., 1995) rollers on which the subject’s own wheelchair can be
mounted. In the table the former is indicated by an asterix after the study reference.
This type of WERG usually affords more sophisticated measurements due to the
independent mounting and therefore ease of instrumentation of the wheels and seat.
The latter addresses important issues relating to the wheelchair-user interface by
allowing the wheelchair user’s own wheelchair to be used during the testing. Goosey
et al. (1998b) indicates the importance of testing athletes in their own racing
wheelchairs stating that through training athletes become tuned to their own racing
wheelchairs.
From the point of view of realistically simulating manual wheelchair propulsion, in
relation to the use of WERGs, two main problems have to be overcome. These relate

36
specifically to the fact that during manual wheelchair propulsion the wheelchair/user
system is fixed in a stationary position.
1) The influence of the HAT motion on wheelchair motion during the recovery
phase when the hands are not in contact with the push-rim.
2) The effect of wind resistance and other environmental factors on the
metabolic cost of wheelchair propulsion and the variation with speed.
Writing specifically about the use of WERGs in anaerobic testing, Vanlandewijck et
al. (2001) highlights another important limitation. Backwards tilting is prevented on
most WERGs. For this reason the forces generated on the push-rims will be much
higher compared with the same task performed under field conditions.
1.2.5.1.2. Motor driven treadmills (MDTs)
MDTs are also common in manual wheelchair propulsion related research. However,
as tables 2, 3 and 4 indicate, MDTs are used less frequently compared to WERGs.
While many MDTs are now specifically manufactured for use in manual wheelchair
research with longer and wider treadmill belts and specific safety devices, much of
the early research was conducted on MDTs designed for runners, modified for use
with wheelchair users. A commonly held opinion is that by using MDTs many of the
disadvantages associated with the use of WERGs can be overcome. While this may

37
be true to a certain extent, MDTs have limitations when compared to over-ground
manual wheelchair propulsion.
MDTs allow accurately simulated manual wheelchair propulsion to be performed in
the laboratory environment. As stated previously, the laboratory environment affords
the researcher far greater opportunity for measurement than field based data
collection. However, A wheelchair fixed to a MDT is no different to a wheelchair
fixed to a WERG. The wheelchair must be fixed to the MDT in such a way that the
wheelchair is allowed to run freely along the whole length of the treadmill belt
(Horvat et al., 1984, Claremont et al., 1985, Lakomy et al., 1987). This allows the
wheelchair to accelerate and decelerate with the natural rhythm of propulsion.
Wheelchair ergometers and MDTs share one limitation in relation to the realistic
simulation of manual wheelchair propulsion. The effect of wind resistance and other
environmental factors on the metabolic cost of wheelchair propulsion, and their
variation with speed. This question has been addressed with respect to runners. Jones
and Doust (1996) state that a 1 % treadmill grade most accurately reflects the
energetic cost of outdoor running. However, to the best of the author’s knowledge
this has not been thoroughly researched with respect to simulated manual wheelchair
propulsion on the treadmill.
1.2.5.1.3. Over-ground manual wheelchair propulsion
The use of over-ground manual wheelchair propulsion provides the investigator with
the opportunity to study realistic propulsion. This is important in the study of manual

38
wheelchair propulsion kinematics and particularly important in the study of racing
wheelchair propulsion. The only limitation of using over-ground manual wheelchair
propulsion is the level of measurement that can be achieved. It is very difficult to
combine the realism of over-ground manual wheelchair propulsion and the carefully
controlled sophisticated measurement environment of the laboratory. At present the
level of measurement afforded by the laboratory environment cannot be replicated
when performing over-ground manual wheelchair propulsion trials. This is the reason
for the dearth of studies using over-ground manual wheelchair propulsion.

39
Table 1 Wheelchair coding for tables 2, 3 and 4
Wheelchair Code Wheelchair Code
Daily use 1 Traveller 11
Crank 2 Active or sport wheelchair 12
Synchronic lever 3 Basketball wheelchair 13
Fully adjustable 4 Racing wheelchair 14
Quickie GPV 5 Three wheeled racing wheelchair 15
Quickie 2HP 6 Four wheeled racing wheelchair 16
Quickie I 7 Own seat cushion used a
Quickie II 8 Personal wheelchair P
Premier II 9 Standard wheelchair S
Morrien Tornado 10 Wheelchair ergometer WERG

40
Table 2 Studies using a wheelchair ergometer to simulate manual wheelchair propulsion
Origin
Study/Studies
Further studies
using WERG
Brief description of
WERG
Wheelchair Special features of
WERG
Type of drive Type of resistance control Additional biomechanical data
collection
Brattgård et al.
(1970)*
None Platform with
separately mounted
adjustable seat and
wheels
S Adjustable seat
and wheels
Chain to Monark Flywheel friction brake None
Stoboy et al.
(1971)
None Wheelchair driving
platform equipped
with rollers
P None Not stated Not stated None
Wicks et al.
(1977, 1983)
None Design based on
Brattgård et al.
(1977). Combination
wheelchair-cycle
ergometer adapted to
allow arm cranking
S None Chain to Monark Flywheel friction brake. Direct
current generator attached to
ergometer drive shaft to measure
wheelchair strike frequency
None
Glaser (1977)* Combination
wheelchair-cycle
ergometer.
S None Chain to Monark Monark flywheel and belt with
adjustable resistance via screw
mechanism
None
Glaser et al.
(1978, 1979)
" " " " " "
Glaser et al.
(1980)
Modified to allow
arm cranking
" " " " "
Brown et al.
(1990)
" " " " " 2D analysis with a high speed
camera

41
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
Lundberg (1980) None Two cycle training
rollers placed side by
side with holding
frame to steady front
wheels
P None Direct to
rollers
Not stated None
Ross and
Brubaker
(1984)*
None Motor compensated
wheelchair
dynamometer with
independent bi-lateral
inputs
Not stated Ability to sample
dynamometer, push-rim
torque, and velocity
Not stated Not stated EMG. Neuromuscular stimulator
Walsh et al.
(1986)
None Custom made
ergometer
S4 None Direct to
rollers
Not stated 2D analysis
Burkett et al.
(1987)*
None Hysterisis brake
ergometer. Wheels
and seat
independently
mounted on
instrumented frame
WERG Horizontal seat
adjustment
Wheels
mounted on
central drive
shaft
Hysterisis brake None
Coutts and
Stogryn (1987)
None Twin roller
wheelchair ergometer
P12 Resistance and distance
measurement
Direct to
rollers
Torque wrench and electric
motor
None

42
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
Eriksson et al.
(1988)
Custom designed
frictionless roller
ergometer with side
mounted flywheels
P None Direct to rollers Flywheel None
Bhambhani et al.
(1991)
" " " " " "
Lees and
Arthur (1988)
None Twin roller
wheelchair
ergometer.
Computer
interfaced
P None Direct to rollers Weighted flywheel friction
brake
None
Niesing et al.
(1988 -
Conference
proceedings,
1990)*
Sophisticated
computer
controlled
ergometer. Wheels
and seat
independently
mounted
WERG Highly adjustable
for investigation of
wheelchair-user
interface. Isokinetic
and isometric force
measurement
Wheels mounted
independently
Motor controlled None
Woude et al.
(1989b)
" " " " " "
Veeger et al.
(1991b)
" " " " " EMG. 3D mirror analysis using a high
speed camera
Veeger et al.
(1991c)
" " " " " "

43
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
Type of drive Type of resistance control Additional biomechanical
data collection
Veeger et al.
(1991c)
Niesing et al. (1988 -
Conference
proceedings, 1990)*
" Niesing et al.
(1988 -
Conference
proceedings,
1990)*
Niesing et al. (1988
- Conference
proceedings,
1990)*
Niesing et al.
(1988 -
Conference
proceedings,
1990)*
Niesing et al. (1988 -
Conference proceedings,
1990)*
EMG. 3D mirror analysis
using a high speed camera
Veeger et al.
(1992a, b, c)
" " " " " 2D analysis using high
speed camera
Janssen et al.
(1993)
" " " " " None
Woude et al.
(1994)
" " " " " "
Dallmeijer et
al. (1994,
1998)
" " " " " 2D analysis
Helm et al.
(1996)
" " " " " EMG. 3D mirror analysis
Linden et al.
(1996)
Dallmeijer et
al. (1996),
Woude et al.
(1997, 1998)
" " " " " None

44
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
Rozendaal et
al. (2000)
See Niesing et al.
(1988 - Conference
proceedings, 1990)*
See Niesing et
al. (1988 -
Conference
proceedings,
1990)*
See Niesing et al.
(1988 - Conference
proceedings, 1990)*
See Niesing et al.
(1988 - Conference
proceedings,
1990)*
See Niesing et al. (1988 -
Conference proceedings,
1990)*
3D analysis
Hughes et al.
(1989, 1992)*
None Computer aided
wheelchair data
acquisition and
physical simulator.
Wheels and seat
independently
mounted on
instrumented frame
S 0.35 m variation in
seating position in
each of the three
orthogonal planes.
Ability to record
kinematics of trunk,
shoulder, elbow and
wrist. 8 channel
EMG facility
Wheels mounted
on central drive
shaft
Not stated None
Samuelsson et al.
(1989)*
None Frame mounted
wheelchair connected
to a Cybex II
isokinetic
dynamometer
S None Chain to Cybex 1/1
ratio
Cybex II None
Gehlsen et al.
(1990)
None Pro Roller. Tach-
generator interfaced to
an Apple computer
P14 None Direct to rollers Not stated 2D analysis using a high speed
camera

45
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
Cooper (1990c) None Internal roller system
equipped with a
Maxon analogue
tachometer and a
Tektronix analogue
data recorder
P14 None Direct to rollers Inertia adjustment Video records obtained
Gayle et al.
(1990a, b)
Commercially
available wheelchair
roller with added
electronic
speedometer and
wheel revolution
counter
S14 None Direct to rollers Friction mechanism None
Rodgers et al.
(1994)
" S12 " " " 3D motion analysis. EMG.
Wheelchair instrumented with a
force-measuring push-rim and
potentiometers in the wheel hubs

46
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
Rodgers et al.
(1998)
See Gayle et al.
(1990a, b)
S6 See Gayle et al.
(1990a, b)
See Gayle et al.
(1990a, b)
See Gayle et al. (1990a, b) 3D motion analysis. Wheelchair
instrumented with AMTI
multicomponent force/torque
transducer
Vosse et al. (1990) Sophisticated
computer controlled
roller ergometer
using a
Proportional,
Integral and
Derivative (PID)
controller
P Ability to simulate
road/track conditions
Direct to rollers PID None
Robertson et
al. (1996)
" S7 " " " SMARTwheel
Cooper et al.
(1996)
" S5 " " " 3D motion analysis. SMARTwheel
Boninger et al.
(1997),
Shimada et al.
(1998)
" S " " " "
Cooper et al.
(1997)
" S7 " " " "
Boninger et al.
(1998)
" S12 " " " "

47
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
O’Connor et al.
(1998),
DiGiovine et
al. (2000)
See Vosse et al.
(1990)
See Vosse et
al. (1990)
See Vosse et al.
(1990)
See Vosse et al.
(1990)
See Vosse et al. (1990) 3D motion analysis
Mâsse et al.
(1992)
None Commercially
available wheelchair
roller. Iron rings
added to roller to
increase inertia
S14 None Direct to rollers Not stated 3D mirror analysis. EMG
Cooper et al.
(1992)
(Conference
proceedings)
CSUS Dynamometer
(No description)
S7 Not stated Direct to rollers Not stated 2D analysis using two cameras.
Modified three channel version
of SMARTwheel
Asato et al.
(1993)
" " " " " "
Meijs (1993) Motor driven single
roller ergometer.
Computer interfaced
P13 Continuous
determination of
torque
Direct to roller Electrically braked None
Hutzler et al.
(1995)
" " " " " "
Woude et al.
(1995)
" S15 " " " "

48
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
Bhambhani et
al. (1994)
Specially
constructed, low
friction steel roller
system. Computer
interfaced
P None Direct to rollers Not stated None
Bhambhani et
al. (1995)
See Bhambhani et al.
(1994)
P14 See Bhambhani et al.
(1994)
See Bhambhani et
al. (1994)
See Bhambhani et al. (1994) See Bhambhani et al. (1994)
Ruggles et al.
(1994)
Two aluminium
rollers connected to a
Cybex II isokinetic
dynamometer
S9, S8, S5 Angular position and
torque measurement
Direct to rollers,
rollers connected
by chain to Cybex
Cybex II None
Davis et al.
(1998)
" S11, S8 " " " 3D analysis
Wang et al.
(1995)
Eagle roller with
adjustable friction
P15 None Direct to rollers Adjustable friction control 3D mirror analysis using a high-speed
camera. Electronic timing device to
detect contact with the push-rim
Wang et al.
(1996)
" P16 " " " Electronic timing device to detect
contact with the push-rim
Chow et al.
(2000, 2001)
" P14 " " " 3D analysis. EMG
Shimada et al.
(1995)
Two-roller
ergometer,
electronically braked.
Computer interfaced
P Torque measurement Direct to rollers Two independently wired
single input electronic loads
None

49
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
Koontz et al.
(2001)
See Shimada et al.
(1995)
See Shimada et
al. (1995)
See Shimada et al.
(1995)
See Shimada et
al. (1995)
See Shimada et al. (1995) Bilaterally mounted SMARTwheel
Mulroy et al.
(1996)
Specially designed
frame and split-roller
drive assembly.
Computer interfaced
S5a None Direct to rollers Inertia adjustment with
removable flywheels
proportional to the weight of
the subject and the wheelchair
Wheelchair wheel instrumented
with strain gauge force
transducers. EMG
Newsam et al.
(1996)
See Mulroy et al.
(1996)
S5a See Mulroy et al.
(1996)
See Mulroy et al.
(1996)
See Mulroy et al. (1996) SMARTwheel
Rao et al.
(1996), Kulig
et al. (1998,
2001), Newsam
et al. (1999)
" S5 " " " 3D analysis. SMARTwheel
Theisen et al.
(1996)
Two interconnected
rollers. Computer
interfaced
S13 WERG has ability to
simulate propulsion on
inclines
Direct to rollers Electronic brake (Merobel) None
Arabi et al.
(1997)
" S " " " Maximum voluntary force on
push-rim measured using a strain
gauge transducer
Goosey et al.
(1998a)
Single roller
ergometer.
Computerised
interfaced. Optical
sensor used to count
roller revolutions
P15 None Direct to roller Belt from roller drives fan 2D analysis

50
Table 2 Continued
Origin
Study/Studies
Further studies
using WERG
WERG
WERG
collection
Goosey et al.
(1998c)
See Goosey et al.
(1998a)
See Goosey et al.
(1998a)
See Goosey et al.
(1998a)
See Goosey et al.
(1998a)
See Goosey et al. (1998a) 3D analysis
Goosey et al.
(2000)
Goosey-Tolfrey
et al. (2001)
" S15 " " " 2D analysis. On-line system
tracking hand path.
Manchester Metropolitan
University force-measuring
push-rim device
Malone et al.
(1998)
None Commercially
available roller
system
S13 None Direct to rollers Not stated 3D analysis

51
Table 3 Studies using a motor driven treadmill to simulate manual wheelchair propulsion
Origin
Study/Studies
Further studies
using MDT
MDT
MDT
Type of drive Type of resistance
control
Additional biomechanical data
collection
Engel and
Hildebrandt
(1973)
None Purpose built treadmill-
ergometer
P1 None Direct to treadmill
belt
None None
Gass and Camp
(1979)
None MDT (No description) P None Direct to treadmill
belt
None None
Gass and Camp
(1984)
" " " " " None
Sanderson and
Sommer (1985)
belt
None 2D analysis
Woude et al.
(1986)
Enraf Nonius, model
3446.
P1 None Direct to treadmill
belt
None Force transducer used to
measure drag force
Woude et al.
(1988a)
" P12, P13 " " " Force transducer used to
measure drag force
Woude et al.
(1988b)
" S14 " " " 2D analysis using a high-speed
camera. Force transducer used to
measure drag force
Meijs et al.
(1989)
" S10 " " Pulley mechanism for
normalisation of power
output
EMG. Force transducer used to
measure drag force
Veeger et al.
(1989a)
" " " " " EMG. 3D mirror analysis using
a high speed camera
Veeger et al.
(1989b)
" S13 " " " 2D analysis using a high speed
camera

52
Table 3 Continued
Origin
Study/Studies
Further studies
using MDT
MDT
MDT
collection
Woude et al.
(1989c)
See Woude et al.
(1986)
S10 See Woude et al.
(1986)
See Woude et al.
(1986)
Pulley mechanism for
output
EMG. 3D mirror analysis
using a high speed camera
Veeger et al.
(1992a)
" " " " " Force transducer used to
measure drag force
Veeger et al.
(1992c)
" Not stated " " " None
Rasche et al.
(1993)
" P1 " " " Force transducer used to
measure drag force
Janssen et al.
(1993)
" S1 " " " "
Janssen et al.
(1994)
" S2, S3, S1, S12 " " Not stated "
Woude et al.
(1994)
" S10 " " Pulley mechanism for
output
"
Lakomy et al.
(1987)
Woodway model ELGZ
adapted for wheelchairs
P None Direct to treadmill
belt
None None
Campbell et al.
(1997)
" P14 " " " "
Pitetti et al.
(1987)
belt
None None

53
Table 3 Continued
Origin
Study/Studies
Further studies using
MDT
MDT
Wheelchair* Special features of
MDT
collection
Hartung et al.
(1993)
None MDT (No
description)
S None Direct to
treadmill belt
None None
Vanlandewijck
et al. (1994)
None MDT (No
description)
S5 None Direct to
treadmill belt
Pulley mechanism including
load cell for normalisation
of power output
3D analysis using two video
cameras. EMG
Spaepen et al. (1996) " S6 " " " "
Goosey et al.
(1995)
Woodway model
ELGZ adapted for
wheelchairs
P14 None Direct to
treadmill belt
None 2D analysis
Goosey et al. (1998b) " " " " " "
Tropp et al.
(1997)
None MDT (No
description)
P None Direct to
treadmill belt
None Force transducer used to
measure drag force
Arabi et al.
(1997)
None Specially constructed
MDT.
S None Direct to
treadmill belt
None None
Arabi et al. (1999) " P14 " " " Maximal voluntary force
measured by strain gauge
transducer

54
Table 4 Studies employing over-ground manual wheelchair propulsion
Study Brief description of test Wheelchair Propulsion surface Additional biomechanical data collection
Higgs (1983) 400 m, 800 m and 1500 m P16 Outdoor running track 2D photographical analysis of wheelchairs from
the front and rear
Higgs (1986) 200 m and 1500 m P14 Outdoor running track 2D Cine analysis
Ridgeway et al. (1988) 800 m P14 Outdoor running track 2D analysis
Coutts and Schutz (1988) 100 m, 200 m, 400 m, 800 m, 1500 m, 5000
m and marathon
P14 Outdoor running track None
Lees and Arthur (1988) 100 m, 200 m and 400 m P14 Outdoor synthetic track None
Hedrich et al. (1990) Coast down trials P14 Smooth concrete apron
around an indoor running
track
Frontal cross-sectional body area.
Nadeau et al. (1990) 30 m sprint P14 Outdoor running track Motion detectors. Touch pad commenced data
collection
Gayle et al. (1990) 1600 m track trials with two (10 inch and 16
inch) sized push-rims
P14 Outdoor running track None
Coutts (1991) Coast down trials S12 Hard-wood gymnasium
floor
Wheelchair instrumented with a magnetic switch

55
Table 4 Continued
Study Brief description of test Wheelchair Propulsion surface Additional biomechanical data collection
Coutts (1992) Coast down trials S12 See Coutts (1991) See Coutts (1991)
Coutts (1994) Coast down trials. Sprint
trials
P13 " "
Bednarczyk and Sanderson (1994) Steady state propulsion S12 Long strips of smooth
canvas placed on a wooden
gymnasium floor
3D analysis. Hand switch to determine contact and
release
Janssen et al. (1994) Activities of daily life P Not stated None
Goosey et al. (1997) 800 m P14 Outdoor running track 2D analysis
Vinet et al. (1998) Coast down trials P1 Tartan track field Deceleration profile calculated from video
recordings
Arabi et al. (1999) Montreal progressive Track Test
(MTT)
P Outdoor running track Maximal voluntary force measured by strain gauge
transducer

56
1.2.5.1.4. Protocols
Incremental testing protocols for wheelchair athletes are numerous. The protocols
used for testing on MDTs vary in terms of increments in speed (Lakomy et al., 1987,
Campbell et al., 1997, Arabi et al., 1999), increments in speed and % grade (Gass
and Camp 1979, 1984, Woude et al., 1986, 1988a, Hartung et al., 1993, Arabi et al.,
1997, Tropp et al., 1997, Goosey et al., 1995, 1998b) and increments in power output
(Rasche et al., 1993). Similar to the variety of protocols used for testing wheelchair
athletes on MDTs, WERG testing protocols share numerous variations. This is
largely due to the wide variety and complexity of their construction. Simple, single
or twin roller WERGs lend themselves to increasing speed protocols measured in
m.s-1
(Goosey et al., 1998c, Theisen et al., 1996), km.h-1
(Bhambhani et al., 1994,
1995), RPM (Coutts and Stogryn 1987) or wheel strike rate (Bhambhani et al.,
1991). Wheelchair ergometers constructed by connecting wheelchairs to Monark
cycle ergometers increase workload intensities at a constant cadence by increasing
the resistance on a flywheel. This is achieved by adding mass to a metal basket or by
tightening a screw mechanism (Brattgård et al., 1970, Wicks et al., 1977, 1983,
Glaser 1977, Glaser et al., 1978, 1979, 1980). More complex, computer interfaced,
designs use increasing increments of resistance through electronic braking to
measure power output in watts (Burkett et al., 1987, Niesing et al., 1988, 1990, Meijs
1993). Testing during over-ground racing wheelchair propulsion is limited due to the
level of measurement afforded by the environment. However, Arabi et al. (1999)
investigated the feasibility and practicality of performing a number of laboratory
based tests in the field. Despite the use of these varied protocols, few investigators

57
have investigated the possibility of an optimal protocol for testing wheelchair
athletes or looked at standardising the protocols used.
Woude et al. (1988a) investigated the effect of two workload strategies, 1)
Increments in velocity at a constant slope and 2) Increments in slope at a constant
velocity, using eight wheelchair marathon racers and basketball players in a standard
wheelchair. Woude et al. (1988a) justify the use of a MDT by citing the opinion of
Schenau (1980) that there is no actual mechanical difference between treadmill and
over-ground locomotion. Woude et al. (1988a) provide further justification stating
that Bassett et al. (1985) reported no variation in oxygen consumption between over-
ground and treadmill running at 0 and 5.7 % slope within the velocity range tested.
The authors reported no strategy effect in the cardio-respiratory parameters
mechanical efficiency (ME), ventilation rate (VE), oxygen uptake ( 2OV! ) and heart
rate (HR). However, the authors did report that the duration of the propulsive and
recovery phases appeared highly dependent on speed and slope respectively. Veeger
et al. (1989b) found that the duration of the propulsive cycle and recovery phase
were shorter for steeper slopes. Vanlandewijck et al. (2001) reported confirmation of
these findings with slope gradients between 1.5 to 6 %. Woude et al. (1988a) also
suggest that 3 minute stages appeared sufficiently long for experienced wheelchair
users to adapt to a given speed and slope combination.
Hartung et al. (1993) investigated the effect of three workload strategies: Increments
in velocity at a constant slope (S); increments in slope at a constant velocity (G); and
progressive increments in speed and slope (C), using seven wheelchair racing and
games players in a standard wheelchair. The authors reported that treadmill test

58
protocols similar to (C) might be the optimal method. Variations in the kinematics of
manual wheelchair propulsion with each of the three protocols were not studied.
Hartung et al. (1993) voiced concerns about realistic testing protocols for wheelchair
athletes stating, a treadmill protocol using only increments in speed may be
unsatisfactory for athletes in order to elicit maximal responses for safety reasons. It is
this opinion that has fostered the use of inclined MDTs in the assessment of racing
wheelchair propulsion. The inclusion of gradients in racing wheelchair testing
increases the physiological response at any given speed (Goosey et al. 1995). This
reduces the need for tests at high velocities because data concerning maximal
performance ( 2OV! Peak, Power, speed or velocity at 2OV! peak, HR, respiratory
variables and blood lactate accumulation) can be at collected at lower velocities.
In response to safety concerns about physiological testing using MDTs at realistic
race speeds Goosey et al. (1995) studied the efficacy of using a 0.7 % treadmill
gradient in eliciting selected physiological responses at slower treadmill speeds using
11 wheelchair athletes in their own racing wheelchairs. Significant (p<0.01)
increases in HR, oxygen consumption and blood lactate were observed. The increase
in treadmill grade resulted in adaptations in the temporal data rather than the
displacement data. The cycle dynamics, cycle time and the number of pushes per
minute, were higher when the grade of the treadmill was increased (p<0.05 and
p<0.01, respectively). The increase in % grade was accompanied by a mean
reduction of 0.4 s in cycle time and an increase of 29 pushes per minute. The authors
concluded that a 0.7 % increase in gradient is sufficient to stimulate an increased
physiological demand without significantly affecting the movement pattern of

59
wheelchair propulsion. The authors also state that this test protocol may be
recommended to examine the physiological and wheelchair propulsion techniques of
the athletes in their own racing wheelchair at realistic speeds
Both Goosey et al. (1995) and Woude et al. (1988a) found variation in the
kinematics of MWP when using gradients during treadmill testing. Therefore, it may
be questioned whether the kinematics of racing wheelchair propulsion on an inclined
treadmill are truly representative of over-ground racing wheelchair propulsion?
Woude et al. (1986) described a method of measuring the force Fd (resistance force
at a constant speed), made up of internal friction, rolling friction and a gravity
component but independent of velocity. The method of measuring the drag or
resistance force described involves performing a drag test during which the subject
remains passive in the wheelchair while it is moved by the treadmill at a constant
velocity. The force is measured using a force transducer fixed “in line”, on the drag
cable, between the wheelchair and the fixed point on the treadmill where the drag
cable attaches.
Woude et al. (1989a) pioneered a pulley system, off which various masses could be
hung, to standardise power output during manual wheelchair propulsion on an MDT.
Studies that have used this system can be seen in Table 3. The system works by
attaching a cable to the rear of the wheelchair and over a pulley suspended at the rear
of the treadmill. The other end of the cable is attached to a mass hanger, which is
suspended below the pulley. A standard power output is achieved first by measuring
Fd for all subjects, as described above, and then adding various masses in the mass

60
hanger. By using these methods the physiological characteristics of racing
wheelchair propulsion can be measured in standardised trials without the use of
inclined treadmills.
Rasche et al. (1993) used the pulley mechanism described above, to increase the
intensity of trials at a constant velocity, during a study conducted to compare a
discontinuous (DP) and continuous-jump maximum oxygen uptake protocol (JMP) in
maximal wheelchair exercise on a treadmill. The DP protocol involved three minute
stages followed by two minutes relative rest. The JMP protocol involved increasing
power output via the pulley mechanism every minute. The paper concluded that both
the DP and JMP protocols were equally appropriate in determining 2OV! peak and
power output at 2OV! peak.
Arabi et al. (1999) investigated the feasibility of three tests, the Montreal progressive
Track Test (MTT), Critical velocity test (Vc) and maximal velocity with lactate
steady state (Vch), previously used in the assessment of runners. The MTT and Vc
were feasible in that the MTT could be performed, and Vc, determined, in the field.
The authors state that the measurements of Vch could not be used because of “many
absurd results”, (p. 489). A second study in a laboratory showed that the concept of
critical velocity and critical power could be used in wheelchair testing on a treadmill.
Similar to the test described by Woude et al. (1986), Vinet et al. (1998) described a
test for the measurement of drag or resistance force, which could be administered in
the field.

61
1.2.5.1.5. Physiological assessment of the wheelchair athlete
The wheelchair/wheelchair-user system is required to perform optimally. However,
optimal performance is governed by the constraints of the athlete’s disability and the
mechanical constraints of the wheelchair. From a physiological standpoint, the
research was sought to determine whether the physiological characteristics that are
thought to govern athletic performance in able-bodied athletes apply to wheelchair
athletes across the disability range?
Physiologically orientated manual wheelchair propulsion research is divided into two
clear areas, aerobic and anaerobic performance. The anomaly that wheelchair athletes
tend to take part in most events from 100 m through to the marathon is very different
to the traditional distinction between sprint and endurance prevalent in able-bodied
athletics. In comparison to the 35 % decrease in the average velocity observed for
100 m and 5000 m World record performance for running, the decrease in the
average velocity for wheelchair racing is only 15 % (Coutts and Schutz 1988).
Hutzler (1998) explains this by stating that in the relatively small active muscle mass
of the arms, local fatigue precedes central factors as the limitation for peak
performance. Janssen et al. (1993) found that there was a strong positive relationship
between upper body isometric strength, sprint power and aerobic power in
individuals with SCI. The authors speculated that this relationship is due to the
shared dependency on active muscle mass together with peripheral muscular exercise
limiting factors. Janssen et al. (1993) postulate that measurement of one variable
might be sufficient to describe (within certain limits) the physical capacity of
individuals with spinal cord injuries. Although not fully longitudinally researched as

62
yet, thoughts are that if significant relationships are found between measurements of
aerobic and anaerobic performance variables then one test could be developed to
measure the physical capacity of wheelchair athletes. This would reduce the
extensive requirement of time and laboratory instrumentation and also the
concomitant effort and cost. One limitation of this line of research is the use of
WERGs in collecting anaerobic performance data. Vanlandewijck et al. (2001) noted
that the fixed nature of WERG testing results in an increase in the force measured at
the push-rims compared with that measured during the same task performed under
field conditions. If one test is to become standard practice, a method of determining
push-rim forces that could be used to test wheelchair athletes under realistic
conditions needs to be developed first.
Conley and Krahenbuhl (1980) described running economy, the energy cost (oxygen
uptake) of working at a constant rate, as being essential to success in running. In
manual wheelchair propulsion, pushing economy is defined as the energy cost of
wheelchair propulsion at a constant speed (Lakomy and Williams 1996). Lakomy et
al. (1987) found pushing economy, defined as the oxygen cost of propulsion at 4 m.s-
1
, returned a value of 0.39 when correlated with 5 km time trial time. The authors
concluded wheelchair propulsion economy did not appear to be major influence on
performance.
Jones et al. (1992) examined the relationship between pushing economy and
wheelchair propulsion technique at 2.69, 3.58, 4.69, 5.36 and 6.25 m.s-1
in male
wheelchair racers on a WERG. Ten athletes were selected from 15 and divided into
two groups, (five most and five least economical, grouped according to 2OV! ). Jones

63
et al. (1992) reported that the economical group had: 1) Less head and trunk velocity
with more elbow and wrist velocity at the strike and release, 2) Released the wheel
with a straighter arm and higher wrist velocity, and 3) Stroked less frequently with
less time in contact with the rim. Jones et al. (1992) state that the economical group
had a more fluid, rhythmic motion, consistent across the speeds tested and concluded
that while an exact mechanism was not clear, a combination of these mechanical
factors may contribute to a decrease in 2OV! at a given speed.
Goosey et al. (1998b) examined the relationship between pushing economy and
selected kinematic variables at realistic racing speeds (6, 6.5 and 7 m.s-1
) in eight
wheelchair racers on a MDT. Large variations in pushing economy were found
between individuals. Goosey et al. (1998b) state that at the speeds detailed above,
economy was associated with: the lighter athletes (r = 0.89, 0.86 and 0.83
respectively); a greater range of elbow movement (r = -0.85, -0.65 and –0.63
respectively) and a lower push rate (r = 0.73, 0.81 and 0.63 respectively). Goosey et
al. (1998b) concluded that the effects of lesion level and wheelchair design might be
more important in explaining differences in pushing economy than differences in
pushing technique. Goosey et al. (1998c) examined the relationship between
economy and selected kinematic variables. This study differed from Goosey et al.
(1998b) in that a 3D analysis was performed of propulsion technique on a roller
WERG at 4.70 and 6.58 m.s-1
. The study found that higher ME and lower push rate
were associated with economy (p< 0.05) and concluded that the magnitude and
direction of forces may be important for determining economy of propulsion. Goosey
et al. (2000) investigated the effect of push frequency on propulsion economy at a set
speed of 6.58 m.s-1
. The study was performed on a roller WERG using eight male

64
wheelchair racers (T4-T8 and SB). Push frequencies of 60, 80, 120 and 140 % of the
individual’s freely chosen push frequency (FCF) were analysed. Goosey et al. (2000)
concluded that push frequency does have an effect on economy with the athlete’s
FCF being the most economical.
The studies detailed above share few uniform characteristics making strict
comparisons difficult. According to a number of researchers (Glaser et al., 1977;
Arabi et al., 1997; Bhambhani et al., 1991, 1994), the use of WERGs in the study of
the physiology of manual wheelchair propulsion is reliable and valid. However, the
validity of the wide variety of WERGs in the assessment of the kinematics of racing
wheelchair propulsion is not so clear (Tropp et al., 1997, Vanlandewijck et al.,
2001). The studies of Jones et al. (1992) and Goosey et al. (1998c, 2000) have
analysed racing wheelchair propulsion on WERGs and attempted to establish the
relationship between the mechanics of racing wheelchair propulsion and economy.
Although these studies provide a firm basis from which research into racing
wheelchair propulsion economy can be continued, the link between racing
wheelchair propulsion kinematics and economy must be studied under realistic
conditions.
The ability of muscles to produce maximal force over a short period of time is
typically referred to as anaerobic power. Originally developed for cycle and arm
crank ergometry, the updated Wingate Anaerobic Test (WAnT) described by Bar Or
et al. (1987) has been modified and adopted as the standard anaerobic power test for
wheelchair athletes (Hutzler 1998). For a more in depth review of the literature

65
relating to the anaerobic fitness testing of wheelchair users, the reader is directed to
Hutzler (1998).
The WAnT protocol described by Bar Or et al. (1987) for wheelchair users facilitates
the measurement of peak power and mean power. Peak power (P5) is the highest
average power of any five-second period during the test. Mean power (P30) is the
average power produced during the test. P5 and P30 refer to the anaerobic maximal
and endurance capacity of the muscles used. In addition the index of fatigue (IOF)
can be calculated. The IOF provides a measure of the power drop off during the test.
Lees and Arthur (1988) conducted three experiments with seven British male athletes
(ISMGF classes 2-5). The first experiment investigated the stability of peak power,
mean power and maximum velocity measurements. Performing three tests over a
five-week period with resistive loads of 1.2 and 1.0 kg. No significant differences
were found between the measurements. The second experiment investigated changes
in peak and mean power output with varying resistive load. Both peak and mean
power showed a linear increase as resistive loads increased from 1.4 to 2.4 kg. In the
third experiment the relationship between peak power, mean power and sprint
performance time over 100, 200 and 400 m were examined. Significant negative
correlations (p<0.01) were found between peak power, mean power, and all
performance times. The authors concluded that the WERG produced reliable results,
that there was no clear optimum load for peak or mean power output and that peak
and mean power output was closely related to performance times.

66
Woude et al. (1997, 1998) studied the anaerobic capacity of 48 elite wheelchair track
athletes (38 male, 10 female), classified into four different function classes. The
studies report class related P30 of 23, 68, 100 and 138 W for the male athletes and 38,
77 and 76 W for the female athletes (upper three classes). Sprint power for the mixed
sex cerebral palsy group was 35 W compared to the 121 W for the mixed sex
amputee group. A significant correlation (r = -0.79) was found between P30 and 200
m sprint performance times. No correlation was found between P5 or P30 and
marathon times. Specifically Woude et al. (1998) reported that sprint power relative
to body weight varied between 0.36 ± 0.03 and 1.85 ± 0.43 W.kg-1
.BM-1
for the
different subject groups. The authors concluded that propulsion technique and
performance parameters are highly variable among wheelchair athletes.
Hutzler (1998) highlighted three main issues relating to the anaerobic fitness testing
literature. Firstly, the type of wheelchair ergometer used may have a considerable
effect on the results Secondly, a number of protocols based on the WAnT appear to
be in use to measure the same variables. Thirdly, There appears to be no agreed
resistance level, optimal or otherwise, for this type of testing.
Invariably anaerobic testing is conducted on a computer interfaced WERG. This
allows peak and mean power to be calculated using simple computer software.
Hutzler (1998) states that the type of ergometer used “reduces the applicability of
comparative interpretations”, (p. 105). This particular limitation relates to the
problems with comparing data from WERGs that provide a uniform wheelchair-user
interface (Niesing et al., 1988, 1990, Vosse et al., 1990) with those on which
individual wheelchairs can be mounted (Shimada et al., 1995, Goosey et al., 1998a).

67
The type of WERG used in each of the studies reviewed above is detailed in table 2
As stated previously, the former usually affords more sophisticated measurements
due to the independent mounting and therefore ease of instrumentation of the wheels
and seat. The latter addresses important issues relating to the wheelchair-user
interface by allowing the wheelchair users own wheelchair to be used during the
testing.
Studies investigating the anaerobic performance of wheelchair users have utilised a
number of protocols modified from the WAnT protocol described by Bar Or et al.
(1987). A test duration of 30 s appears to be common to most studies. However,
Woude et al. (1994) performed tests of 20 seconds duration. One common variation
in the WAnT protocol is the use of and the intensity of the rolling start. The WAnT
protocol advocated by Bar-Or (1987) suggests a rolling start. Coutts and Stogryn
(1987) allowed subjects to perform a rolling start at 75 % of max speed. Lees and
Arthur (1988) used a set start speed of 60 % of the maximum flywheel velocity.
Janssen et al. (1993) used a rolling start at near maximal effort. Dallmeijer et al.
(1994) provided no quantification for the rolling start. Woude et al. (1997, 1998)
performed testing with no rolling start.
Lees and Arthur (1988) states that there appeared to be no clear optimum resistive
load. Studies conducted by Dallmeijer et al. (1994) and Janssen et al. (1994) selected
resistance loads of 0.25, 0.5 or 0.75 N.kg-1
.BM-1
in order to restrict wheelchair
velocity to below 3 m.s-1
to avoid coordination problems at high velocities. Similarly
Woude et al. (1997, 1998) used resistance loads set at 2.5, 5, 7.5 or 10 % of the
combined subject and fictional wheelchair (20 kg) mass to restrict their subjects to a

68
maximum velocity of 3 m.s-1
. In Coutts and Stogryn (1987) tests were repeated using
a higher resistance (undisclosed) if the subject exceeded a maximum of 100 RPM.
Conversely, Hutzler (1995) reported the use of a maximal velocity protocol, which
used minimal resistance in order to achieve velocities representative of those during
actual track and basketball performance. To the best of the author’s knowledge the
optimal resistance for wheelchair users performing the WAnT is still not known.
Hutzler (1995, 1998) recommended the standardisation of braking load in roller
ergometry. It is the recommendation of the author that standardisation of the method
of reporting of resistive loads as a percentage of the subject or
wheelchair/wheelchair-user system mass should also be considered. Standardisation
of anaerobic testing of wheelchair users in terms of the protocols and resistive loads
used and the reporting of data would produce meaningful results and aid
comparisons between studies.
1.2.5.1.6. Biomechanical assessment of the wheelchair athlete
As stated previously, to the sport scientist the wheelchair/wheelchair-user system
poses a similar problem to that of any athlete whose interaction with a specific piece
of equipment brings about a sporting performance. From a biomechanical standpoint,
the interaction of the athlete and the wheelchair, brought together as a single
wheelchair/wheelchair-user system, poses an interesting performance question. How
can the wheelchair athlete bring about optimal performance given the relatively small
forces that can be produced by the muscle mass of the upper extremity?

69
Invariably, when collecting kinematic data during racing wheelchair propulsion the
investigator is concerned with propulsion technique for descriptive analysis (Goosey
et al. 1997, Higgs 1983, Ridgeway et al. 1988) or in relation to an intervention such
as manipulation of the wheelchair/wheelchair-user interface (Walsh et al., 1986,
Gayle et al., 1990a, b, Woude et al., 1988b). The use of 2D analysis is limited in that
the particular subject of the analysis needs to be perpendicular to the optical axis of
the camera and be of sufficient size to facilitate accurate digitising of anatomical
landmarks or other points of interest when analysing the film. In this respect the most
reliable information that can be obtained from 2D film analysis relate to the timing
parameters of the propulsive cycle. Roeleveld et al. (1994) states that 2D analysis
was suitable for stroke, timing and displacements of segments in the sagittal plane.
For this reason studies employing 2D film analysis, with a single camera, have either
only been able to analyse one propulsive cycle during over-ground racing wheelchair
propulsion at specific points in an event (Goosey et al., 1997, Higgs 1983, Ridgeway
et al., 1988), or have had to compromise in order to analyse multiple propulsive
cycles using simulated racing wheelchair propulsion on stationary devices such as
WERGs (Cooper 1990, Gehlsen 1990, Goosey et al., 1998a, 2000) or MDTs
(Goosey et al., 1998b).
Three dimensional film analysis using the direct linear transformation (DLT) method
(Abdel-Aziz and Karara, 1971) is one of the most popular techniques for
reconstructing the location of objects in 3D space. 3D film analysis allows
investigation of the true complexity of racing wheelchair propulsion by making it
possible to map the locations of segments allowing accurate calculation of shoulder
and elbow angles during the propulsive cycle (Goosey et al., 1998c, O’Connor et al.,

70
1998). However, an optimal 3D analysis, using gen-locked cameras, is restrictive.
Control points (points with known locations) must be distributed within the activity
space. In addition, the cameras need to be fixed. This usually precludes analysis of
over-ground propulsion. Veeger et al. (1991a) pioneered a method of performing a
3D analysis using a single camera and a mirror. This approach has since been used in
other studies (Helm et al., 1996, Mâsse et al., 1992, Wang et al., 1995). This method
precludes analysis of over-ground propulsion for the same reason.
Pan and tilt videography allows cameras to follow the motion of an object by rotating
about the horizontal and/or the vertical axes (pan and tilt respectively). This allows a
large subject image to be maintained at all times. These systems use specially
machined tripod heads each containing two optical encoders. The optical encoders
are aligned to sense the angular positions of the cameras. One encoder is aligned
vertically to measure pan positions, while the other horizontally, to measure tilt. This
method is called the integrated rotating camera (IRC) method. Systems using the IRC
method allow 3D film analysis to be performed over a large area by allowing
cameras to pan and tilt to follow the subject of the analysis within a pre-calibrated
space. These systems currently provide the best method of conducting film analysis
during over-ground manual wheelchair propulsion. However, to the best of the
author’s knowledge these systems have not yet been used in the study over-ground
racing wheelchair propulsion.
Typically the instant the hand contacts and releases the push-rim is identified from
the images recorded during the kinematic analysis. However, this can be difficult
even with the most sophisticated motion analysis systems. Bednarczyk and

71
Sanderson (1994) and Wang et al. (1996) describe instruments designed to
accurately identify these stroke parameters. The devices used in both studies utilised
a switch mechanisms in the wheelchair user’s glove. Bednarczyk and Sanderson
(1994) wired the switch mechanism via a comparator to a LED placed in view of the
cameras. The resolution of the device was therefore determined by the 60 Hz sample
frequency of the cameras. Wang et al. (1996) independently wired switches from the
thumb, index and middle fingers to LED’s and sampled separately at 200 Hz using a
microcomputer. In this way Wang et al. (1996) were not only able to identify the
instants of contact and release, determining the durations of the propulsive and non-
propulsive phases, but were also able to identify the order in which the fingers
contacted the push-rim.
Nadeau et al. (1990) used a pressure sensitive pad and motion detectors in an
investigation of the mechanical power output of world-class wheelchair athletes.
Motion detectors, positioned at 4 and 5 m of every 5 m portion of a 30 m section of
running track, were activated when the wheelchair moved away from a pressure
sensitive pad over which it was positioned at the start line. As the wheelchair passed
in front of each motion detector a time was recorded. Split times were sent by
telemetry to a central receiver.
Coutts (1991) describes an instrument with the ability to detect and quantify
wheelchair motion. The device used a magnetic switch fixed to the wheelchair. The
switch was activated using two magnets, 180° apart, attached to the spokes of one
rear wheel. Coutts (1992, 1994) use the same instrument. Coutts (1992) uses one
wheelchair instrumented with the speed sensing system in order to describe the

72
dynamics of wheelchair basketball. In Coutts (1994) the device was transferred
between the wheelchairs of individual athletes in order to investigate the drag and
sprint performance of wheelchair basketball players. Although the device used by
Coutts provides a method of measuring wheelchair velocity during over-ground
athletic wheelchair propulsion, the resolution (two samples per revolution) is
insufficient to accurately determine intra-push wheelchair velocity. Vanlandewijck et
al. (2001) state that during the propulsive cycle the hand can be in contact with the
push-rim for anywhere between 71.0 and 121.7 ° of rear wheel rotation. Clearly
sampling every 180 ° of rear wheel rotation is insufficient to provide accurate data
regarding intra-push changes in wheelchair velocity. It is very important to be able to
accurately measure both the velocity of steady state wheelchair propulsion and the
changes in wheelchair velocity that occur due to the kinematics of propulsion.
Accurate measurement of these variables is fundamental to the assessment of
wheelchair athletes.
The ability to measure push-rim forces directly is important as it provides
information about how the force developed by the individual is directed. This
information can be used to describe and therefore improve stroke biomechanics
(Goosey-Tolfrey et al., 2001) (by maximising the force tangential to the push-rim),
to reduce injuries (by correcting for damaging stroke biomechanics), and to improve
wheelchair design. A number of investigators have attempted to tackle the problem
of how to collect kinetic data during racing wheelchair propulsion. The most popular
methods appear to be the use of instrumented, force-measuring, or SMARTwheels
(Cooper and Cheda 1989, Strauss et al., 1989, Watanabe et al., 1991, Asato et al.,
1993, Sickle et al., 1995, Stojak 1997, Wu et al., 1998) or complex WERGs with the

73
ability to measure propulsion torque at the wheel hub (Niesing et al., 1988, 1990,
Ruggles et al., 1994). Other methods involve the use of static simulations of
wheelchair propulsion. Typically these devices are in the form of WERGs with
wheels that are blocked using force-measuring devices (Janssen et al., 1993, Arabi et
al., 1999, Brauer and Hertig 1981), instrumented, restrained platforms (Brubaker et
al., 1981) or force platforms (Tupling et al., 1986). Much of the credit for the
development of force-measuring wheels during the 1990’s should go to Cooper who
appears to have lead the drive for more in depth investigation of wheelchair
locomotion. Cooper authored and co-authored a number of papers in which the need
for instrumentation was emphasised (Cooper and Cheda, 1989, Cooper 1990a, b, c,
d, Vosse et al., 1990). Cooper et al. (1997), put forward a standardised method for
determining forces and moments.
Cooper and Cheda (1989) describe a wheel specifically designed for the
measurement of racing wheelchair propulsion forces/torques using beams
instrumented with strain gauges. The force/torque applied to the push-rim causes a
deflection of the beams, which is measured via strain gauges. The method outlined
has the ability to accommodate the individual athlete’s push-rims and racing
wheelchair. This early device is restrictive because it is wired directly into a
microcomputer. Variations of this device have been developed by Strauss et al.
(1989), Watanabe et al. (1991), Asato et al. (1993), Sickle et al. (1995), Stojak
(1997) and Wu et al. (1998).
Table 2 indicates the studies that have used these devices on a WERG during
simulated manual wheelchair propulsion. Very often the ideology of testing athletes

74
is infringed upon in these studies. A standard wheelchair equipped with the force-
measuring wheel is typically used in these studies. Force-measuring wheels are
heavier than normal wheels. It is also very difficult for investigators using and
developing these devices to allow for the wide variation of push-rim sizes and tube
diameters. Fundamental factors such as the distance of the push-rim from the surface
of the wheel and the variation in materials with which the push-rims are covered
cannot be completely replicated for each athlete tested. Experienced wheelchair
athletes know how important these factors are in bringing about optimal racing
wheelchair propulsion. Even those wheels that are able to closely replicate those of
the athletes (Cooper and Cheda 1989) suffer from one major limitation. To the best
of the author’s knowledge, a device still does not exist that can be used to measure
push-rim forces/torques during over-ground racing wheelchair propulsion. Therefore,
it can be concluded that we still do not have an accurate idea of the forces and
torques generated during over-ground racing wheelchair propulsion.
The use of electromyography (EMG) in manual wheelchair propulsion literature is
well documented Tables 2 and 3 detail the number of studies that have used EMG
during simulated manual wheelchair propulsion on WERGs and MDTs respectively.
Similar to the use of force-measuring wheels, measurement of the electrical activity
of the muscles used during manual wheelchair propulsion typically requires
connection to a microcomputer to allow the large volume of data that is generated to
be collected. For this reason studies using EMG simulate manual wheelchair
propulsion using WERGs or MDTs. However, unlike the collection of kinetic data,
the measurement instrument is applied to the subject and not the wheelchair. This
means that subjects are able to use their own wheelchairs. Unfortunately, out of all of

75
the studies detailed in tables 2 and 3 that have used EMG, only Chow et al. (2000,
2001) has collected EMG data from athletes in their own wheelchairs.
Chow et al. (2000) investigates the effect of resistance load on the biomechanical
characteristics of racing wheelchair propulsion. Chow et al. (2001) provides a useful
comparison between the conventional and para-backhand pushing techniques. Both
studies performed 3D kinematic analyses and EMG analyses of eight muscles of the
right hand side of the body. Unfortunately, the data collected by Chow et al. (2000,
2001) were collected during simulated racing wheelchair propulsion on a WERG.
Although these studies provide the best description of the electrical activity and
activation pattern of the muscles during racing wheelchair propulsion, it can be
concluded that we still do not have data from EMG studies collected during over-
ground racing wheelchair propulsion.
1.2.6. Summary
This literature review has attempted to provide an overview of manual wheelchair
propulsion research with particular importance placed on research relating to racing
wheelchair propulsion under realistic conditions. The importance of the ergonomic
approach to the study of manual wheelchair propulsion by attempting to optimise the
wheelchair-user interface has been shown. The effect of the growth and maturity of
wheelchair sport in influencing the design of racing wheelchairs has also been
shown. The increased demands of wheelchair sport with respect to “daily use”
manual wheelchair propulsion provide a further argument for optimising the

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