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A comparison of functional mobility in standard vs. ultralight wheelchairs as measured by performance on a community obstacle course

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Appropriate wheelchair prescription requires maximizing user function while justifying cost. The purpose of this study was to investigate differences in a user's performance of mobility skills (on a community obstacle course) between an ultralight (UWC) and standard wheelchair (SWC). Subjects: Sixty healthy adults (mean = 28.3 years) without wheelchair experience performed one course trial. Participants were randomly assigned to an UWC or a SWC. Researchers recorded time for completion, Rating of Perceived Exertion (RPE), and number, location, and types of errors committed. Errors included contact of WC and any obstacle, front casters leaving the ground, or loss of directional control (veering). A MANOVA of the data (p < 0.05) showed a significant difference in numbers of contact errors (higher in the SWC) and castor errors (higher in the UWC) between the two wheelchairs. Number of veering errors, time to complete, and RPE were not significantly different. Differences in wheelchair design can lead to differences in a user's performance of functional mobility skills. Choice of wheelchair may affect a user's ability to be independent in a community setting.
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ASSISTIVE TEC HNOLOGY
A comparison of functional mobility in standard
vs. ultralight wheelchairs as measured by
performance on a community obstacle course
HELEN ROGERS*, SEAN BERMAN, DENNIS FAILS and
JOUMANA JASER
Department of Physical Therapy, School of Allied Health Sciences, The University of Texas
Medical Branch, Galveston, Texas, USA
Accepted for publication: May 2003
Abstract
Purpose: Appropriate wheelchair prescription requires max-
imizing user function while justifying cost. The purpose of this
study was to investigate differences in a user’s performance of
mobility skills (on a community obstacle course) between an
ultralight (UWC) and standard wheelchair (SWC).
Subjects: Sixty healthy adults (mean = 28.3 years) without
wheelchair experience performed one course trial.
Methods: Participants were randomly assigned to an UWC or
a SWC. Researchers recorded time for completion, Rating of
Perceived Exertion (RPE), and number, location, and types of
errors committed. Errors included contact of WC and any
obstacle, front casters leaving the ground, or loss of directional
control (veering).
Results: A MANOVA of the data ( p 5 0.05) showed a
significant difference in numbers of contact errors (higher in
the SWC) and castor errors (higher in the UWC) between the
two wheelchairs. Number of veering errors, time to complete,
and RPE were not significantly different.
Conclusions: Differences in wheelchair design can lead to
differences in a user’s performance of functional mobility
skills. Choice of wheelchair may affect a user’s ability to be
independent in a community setting.
Introduction
A major dilemma for physical rehabilitation profes-
sionals in today’s dynamic health care system is provid-
ing a wheelchair prescription that maximizes an
individual’s function and independence and justifies
the cost.
1, 2
Many third party payers have been reluctant
to reimburse for ‘sports’ or ultra-light wheelchairs
(UWCs) due to higher costs and perceptions that UWCs
are suitable only for wheelchair athletes.
3
However,
because clinicians perceive that the unique modifications
offered by these chairs allow for increased mobility,
ultra-light wheelchairs are frequently being recom-
mended for individuals who are not athletes.
1
Research
has demonstrated that changes in the design of a wheel-
chair results in positive changes in energy cost, joint
kinematics and propulsion biomechanics. In general,
the design of the UWC places the axle forward of the
centre of gravity of the user. This has been shown to
decrease rolling resistance and increase propulsion effi-
ciency
4
as well as decreasing upper extremity electro-
myogram (EMG) readings and increasing the
smoothness of pro pulsion.
5
Also, the ability to adjust
the seat height of the UWC in relation to axle position
has been shown to have positive effects on cardiovascu-
lar parameters, energy cost, and propulsion technique;
all of which can improve propulsion biomechanics.
6
Yet most wheelchairs covered by Medicare or other
third party payers have a standard design with non-
adjustable rear axles placed posterior to the user’s center
of gravity and fixed seat positions.
7
New design techniques, materials, and engineer ing
have not only made wheelchairs lighter, but also more
durable, adjustable, and maneuverable.
1, 8–11
However,
there is little published evidence to demonstrate that
differences in wheelchair design produce difference in
the functional mobility of the user in the community
setting. Currently, 96.2% of wheelchair users in the
USA have some degree of functional limitation and
85.7% are unable to perform one or more of the eight
* Author for correspondence; Helen Rogers PT, MA,
Department of Physical Therapy, School of Allied Health
Sciences, UTMB, 301 University Blvd., Route 1144, Galves-
ton, Texas, 77555-1144, USA. e-mail: hrogers@utmb.edu
DISABILITY AND REHABILITATION, 2003; VOL.25,NO. 19, 1083–1088
Disability and Rehabilitation ISSN 0963–8288 print/ISSN 1464–5165 online
#
2003 Taylor & Francis Ltd
http://www.tandf.co.uk/journals
DOI: 10.1080/0963828031000152048
mobility-related functions as defined by the National
Health Interview Survey on Disability (NHIS-D).
12
In
order to prescribe the optimal wheelchair, therapists
need to determine whether there is a baseline difference
in functional mobility at a community level that can be
attributed directly to the wheelchair’s design or config-
uration regardl ess of a users pathology or experience
level.
Until now, wheelchair research has primarily focused
on the metabolic cost,
13 15
joint kinematics
16 18
and
mechanical efficiency
6, 19 21
of specific wheelchair designs
or parameters. In addition, more clinically aimed wheel-
chair studies have looked at differences in metabolic
physiology/functional mobility in patients with identi-
fied pathologies, such as spinal cord injuries.
13, 22, 23
Only
a few studies have attempted to compare one wheelchair
design to another on parameters of function.
23, 24
Most
studies have investigated the effect on propulsion of
changing an individual parameter of a wheelchair, such
as degree of wheel camber or hand rim size, rather than
the effect of changes in overall wheelchair design. Final-
ly, no studies have examined functional mobility in a
community environment versus a laboratory or
controlled setting.
Several studies have looked at differences between
wheelchairs of different design in physiological para-
meters be tween subjects with a disability.
13, 22, 23
Two
studies, Parziale
22
and Beekman, Miller-Porter, and
Schoneberger,
23
both found differences between subjects
with paraplegia and those with tetraplegia but neither
study failed to conclusively attribute these differences
to the type of wheelchair as opposed to the level of the
subject’s lesion. Also, the propulsion tasks in these
studies were carried out in a controlled setting rather
than the community. Hilbers and White
13
found a differ-
ence between the wheelchairs on a controlled velocity
task as well, but with a very homogeneous group of
subjects, none of whom had lesions that involved the
upper extremities.
In a pilot study with able-bodied subjects emphasizing
the effect of wheelchair design on community function,
we determined that there was no significant difference
in time to complete task between a SWC and an UWC
when propelling up a ramp and through a door.
24
We
did, however, find that there were significantly more
errors committed when propelling the UWC through
the door.
Cooper and his team
8, 9, 11
have provided a database of
studies focusing on the durability and cost effectiveness
of depot (SWC), lightweight (LWC) and rehabilitation
(UWC) wheelchairs using the American National Stan-
dards Institute/Rehabilitation Engineering and Assistive
Technology Society of North America (ANSI/RESNA)
standards. They found that, of the three wheelchair
types, the UWC was the most durable and had the best
value over its life span. Their data indicated that the
UWCs lasted 13.2 times longer in fatigue tests and were
3.4 times cheaper to operate than the SWCs tested.
These investigators also commented on the high degree
of adjustability of the UWC and speculated that adjust-
ability can increase the mobility of the user and reduce
the risk of secondary injury or disability.
8, 9, 11
None of these studies can convincingly say that one
wheelchair design is significantly superior to another in
a community setting or that the wheelchair design can
influence function among individuals with varying types
of disability. This study was designed to investigate the
effect of wheelchair design on mobility in a community
setting separate from the effects of pathology or train-
ing. We used a post-test only control group design to
compare the performance of healthy adults using an
UWC and a SWC on an obstacle course in a community
setting. Performance variables included the time to
complete the course, number, location and type of
errors, and a perceived rating of exertion (RPE).
Subjects
We recruited 60 healthy adults who were novice
wheelchair users from a population of University of
Texas Medical Branch at Galveston employees, students
and family/friends of UTMB personnel using e-mail
broadcasts and flyers on campus. This study targeted
adults within an age range of 19 to 55; no attempt was
made to include elderly adults or children. We collected
a sample of convenience that included 29 males and 31
females with a mean age of 28.3 years (range = 20
47). Subjects were randomly assigned to propel either
the UWC (n = 29) or SWC (n = 31) through an obstacle
course. In an attempt to rule out a training effect, we
excluded applicants with more than 3 h of wheelchair
propulsion experience in the past 12 months.
Data collection and analysis
Prior to attempting the obstacle course, all subjects
completed a health screen to rule out any limitations
due to a history of cardio-respiratory or musculoskeletal
impairment involving the hands, arms, shoulders, back
or neck (appendix 1). Even though the risks of complet-
ing this study were minimal, exclusion criteria were strict
to prevent any adverse occurrence. An answer of ‘yes’ to
the presence of any coexisting medical condition (includ-
ing pregnancy) that might compromise a pe rson’s ability
H. Rogers et al.
1084
to propel a wheelchair with maximal effort served as a
criteria for exclusion from the study. Subjects were
informed of the possible health risks including hand blis-
ters, falls, and heat stress. Subjects wore gloves to
prevent blisters, and we fitted the wheelchairs with
anti-tip bars to prevent falls. The trials took place on
an outside obstacle course set on the UTMB campus.
Trials took place in the early morning during the
summer, and subjects were monitored closely for signs
of heat stress. The UTMB Institut ional Review Board
approved the study and exclusion criteria and all
subjects completed a written consent form.
Subjects were given a verbal description of the obsta-
cle course and the various obstacles they would
encounter prior to their first trial. The verbal instruc-
tions were scripted to assure consistency. The subjects
did not receive prompts during the trials except to
assure proper direction on the marked obstacle course.
We chose obstacles commonly encountered on our
campus and considered general to a community setting.
The obstacle course was 1578 feet in length and
included three separate ramps with an average rise to
run of 1 : 16 feet, two doorways of 35-inch width,
two standard 7-inch curb cuts each 85 inches in length,
a simulated elevator task, and a slalom course through
six cones set 7 feet apart. Subjects had to negotiate all
obstacles without help from the examiners or pe des-
trians and were not allowed to use their feet in any
way. We informed the subjects that they were being
timed but instructed them to move at a comfortable
pace because we were also examining other aspects of
wheelchair prop ulsion in addition to the time to
complete the course. Subjects were not given the defini-
tion of errors or informed that errors were being
counted.
Two researchers performed the data collection. One
researcher was responsible for counting errors and iden-
tifying error location while the other timed the trial and
maintained direction on the course. The same researcher
collected each type of data for each subject to assure
maximum inter-trial reliability. The researchers piloted
the course with five non-subject volunteers to reduce
any potential intra-rater variability. We documented
completion time, number of errors, and RPE (rate of
perceived exertion) for each subject as well as the type
of error (castor, contact and veering errors) and the
specific obstacle or position in the course where each
error occurred (doorway, ramps, curb cuts or straight-
aways). Castor errors were defined as loss of contact
between the wheelchair castors and the ground. Contact
errors occu rred when the wheelchair touched any archi-
tectural barriers. Veering errors involved loss of direc-
tional control of the wheelchair, for example, veering
off to one side of the sidewalk during propulsion.
We used a multivariate analysis of variance (MANO-
VA) to analyse the differences in the performance vari-
ables between the trials performed in the SWC and
those performed in the UWC. We analysed all data at
the 0.05 alpha level using SPSS (SPSS, Chicago, Ill.)
statistical software.
Results
Table 1 summarizes the means and standard devia-
tions (SDs) for errors by type (contact errors, castor
errors, veering errors), completion times, and RPEs for
each group. Table 2 identifies the means and SDs of
the types of errors made according to the geography
of the obstacle course (ramps, curbs, steering, and door
errors).
The MANOVA indicated an overall significant differ-
ence in functional mobility between the UWC and SWC
(Hotelling’s T
2
= 0.344, p = 0.006, power = 0.874). Post
hoc univariate analyses indicated significant differences
in the contact (p = 0.021) and castor (p = 0.001) errors
between the two chairs. The number of veering errors
(p = 0.968), RPE (p = 0.492), and completion time
(p = 0.084) did not differ significantly between the two
groups.
When errors were analysed according to location (i.e.,
ramps, curbs, straight aways, and doors), post hoc
univariate analyses indicated significant differences in
errors that occurred with ramps (p = 0.009) , curbs
Table 1 Mean and SD of errors by type, RPE, and completion time
Outcome variables
SWC
MEAN/SD
UWC
MEAN/SD
Univariate
analysis
Contact error 21.06/14.60 13.52/9.26 p = 0.021
Castor error 3.55/4.70 12.62/13.16 p = 0.001
Veering error 1.77/2.17 1.79/1.35 p = 0.968
RPE 5.68/1.89 5.38/1.40 p = 0.492
Completion time 10:19/3:41 8:45/3:10 p = 0.084
Significant at a = 0.05
Table 2 Mean and SD of errors by location
Location of errors
SWC
MEAN/SD
UWC
MEAN/SD
Univariate
analysis
Ramp 2.32/3.37 6.41/7.64 p = 0.009
Curb 1.81/2.64 3.45/3.19 p = 0.034
Steering (straight-away) 3.29/2.62 5.03/5.24 p = 0.105
Door 18.97/13.63 12.76/8.83 p = 0.042
Significant at a = 0.05
A comparison of functional mobility in standard vs. ultralight wheelchairs
1085
(p = 0.034), and doorways (p = 0.042). The incidence of
steering errors (p = 0.105) was similar between the two
wheelchairs.
Discussion
The results of this study indicate that there is a signif-
icant difference in the functional mobility of healthy
adults when using an UWC and a SWC. We attributed
this difference primarily to the number of contact errors
(highest for the SWC) and castor errors (highest for the
UWC). Veering errors were not different between
subjects who used the two wheel chair types, nor did they
differ on their completion times or RPE.
We believe that the significant errors (contact and
castor) are related to the wheel chair design. The SWC
is larger, longer (due to footrest position) and heavier
than the UWC. The increased number of contact errors
supports the supposition that the SWC would be more
difficult to manoeuver especially in narrow spaces or
areas with a greater number of architectural barriers.
Indeed, there were significantly more errors for the
SWC in the location of doorways. The UWC, due to
its forward axle position relative to the center of gravity
of the user, is less stable to the rear and tips more read-
ily.
7
This tendency, combined with the lighter weight of
the UWC, explains the increased caster errors noted for
the UWC; these errors seemed to be primarily associated
with manoeuvering on elevated surfaces such as ramps
and curb cuts. We belie ve the distribution of types of
errors to types of wheelchairs to be clinically significant,
as it appears that the types of errors noted in the UWC
are more easily corrected by user experience than those
of the SWC. The most impor tant factor in controlling
the attitude of the wheelchair around the axis of pitch
(i.e. controlling the ‘tippiness’ of the wheelchair) has
been found to be appropriate manipulation of the user’s
head and upper trunk segment around the center of
gravity.
4
This ability to move and alter the dist ribution
of body weight in relation to the axle is a learned skill.
Rodgers et al. found improvements in the biomechanical
efficiency of propulsion after train ing (including trunk
position).
25
Therefore the number of castor errors can
be affected by user experience as they learn to manipu-
late their body weight in relation to the wheelchair axle
and their own center of gravity. The contact errors
noted in the SWC, however, are due to aspects of the
chair design such as length, width and size that are not
easily affected by the user. Therefore, the UWC users
have more potential to improve fun ction and decrease
errors as their understanding of the biomechanical
advantages of the UWC improves. This improvement
may have a clinically significant effect on functional
propulsion as the user gains experience.
No significant difference was found between the
wheelchairs for veering errors or for RPE. We conclude
that this is due to the inexperience of the subjects.
Because the subjects were able-bodied adults with mini-
mal to no wheelchair experience, both wheelchairs
proved equally difficult to manage initially. Subjects
exhibited an equal amount of difficulty with steering
and propulsion regardless of wheelchair assignment
due to the novelty of the task. Efficiency with wheelchair
propulsion, however, has been shown to improve with
experience.
26
Studies have shown that wheelchair
propulsion differs between skilled and non-skilled users
in the parameters of work output, mechanical efficiency,
and efficiency of propulsion.
27 30
However, we also
believe that the potential to improve in wheelchair func-
tion is higher when using an UWC. The UWC has a rear
axle position and smaller shoulder-to-push rim distance
that has been correlated with better fun ctional perfor-
mance.
6
Studies have shown that as the centre of gravity
is moved in a direction rearward and downward relative
to the axle, the propulsion patterns exhibit improved
mechanical efficiency,
6, 31
lowered EMG readings and
improved biomechanics,
5, 7
and enhanced performance.
4
Because these features of the UWC may improve
propulsion style with training, the user may also experi-
ence relatively fewer errors and lower RPE ratings than
users of a SWC. This would translate into better func-
tional mobility in the community for the UWC user
than for the SWC user.
Although the difference in completion time on this
obstacle course was not statistically different between
the two wheelchair groups, the UWC group demon-
strated a mean speed that was 1 min 34 s faster than
the average SWC speed (SWC = 10 min 19 s,
UWC = 8 min 45 s). This may be clinically significant.
Considering that a long community distance could
require as much as 30 min to traverse, the UWC may
potentially reach the terminal point approximately
4 min faster. If UWC users become more proficient than
SWC users as speculated, this time difference could
reduce overall fatigue and musculoskeletal stress.
This study utilized a populati on of subjects without
physical disabilities. While this helped assure a ‘novice’
status with regards to wheelchair propulsion, we are
unable to address how performance on the obstacle
course might have been affected by experience. There-
fore, one must be cautious not to generalize the results
of this study to individuals with various types of physi-
cal disabilities or to individuals with wheelchair propul-
sion experience. Given the location of the obstacle
H. Rogers et al.
1086
course, this study may not generalize to significantly
different community environments, especially those in
hilly or very urban areas. Further research is needed
to further investigate the effect of wheelch air design on
functional performance, especially the performance of
experienced users who independently manage their
mobility in a community setting.
Conclusion
Novice wheelchair users who manoeuvered a commu-
nity-based obstacle course in UWCs had fewer mobility
errors and faster completion times than those who use
SWCs. This difference may be attributed to design para-
meters of the wheelchairs but is also likely to be dependent
on experience of the user. Further research is needed to
delineate factors inherent in the wheelchair design versus
performance variables attributed to the user in order to
improve wheelchair prescription, maximize functional
mobility in the community, and justify reimbursement.
Acknowledgements
We acknowledge Dr. Martha Hinman PT, EdD with gratitude for
her expertise and advice with editing.
References
1 Ragnarsson K. Prescription characteristics and a comparison of
conventional and lightweight wheelchairs. Journal of Rehabilitation
Research and Development 1990; 2: 8 16.
2 Mattingly D. Wheelchair selection. Orthopedic Nursing 1993; 2:
17 27.
3 Crase N. Survey of lightweight wheelchair manufacturers: The
sport chair of yesterday is the everyday chair of today. Sports’ N
Spokes. 1985; 10: 30 35.
4 Brubaker C. Wheelchair prescription: an analysis of factors that
affect mobility and performance. Journal of Rehabilitation Research
and Development 1986; 23(4): 19 26.
5 Masse L, Lamontagne M, O’Riain M. Biomechanical analysis
of wheelchair propulsion for various seating positions. Journal
of Rehabilitation Research and Development 1992; 29(3):
12 28.
6 van der Woude L, Veeger D, Rozendal R, Sargent T. Seat height in
handrim wheelchair propulsion. Journal of Rehabilitation Research
and Development 1989; 26(4): 31 50.
7 Boninger M, Baldwin M, Cooper R, Koontz A, Chan L. Manual
wheelchair pushrim biomechanics and axle position. Archives of
Physical Medicine and Rehabilitation 2000; 81(5): 608 613.
8 Cooper R, Gonzalez J, Lawrence B, Renschler A, Boninger M, van
Sickle D. Performance of selected lightweight wheelchairs on
ANSI/RESNA tests. Archives of Physical Medicine and Rehabilita-
tion 1997; 78: 1138 1144.
9 Cooper R, Boninger M, Rentschler A. Evaluation of selected
ultralight manual wheelchairs using ANSI/RESNA standards.
Archives of Physical Medicine and Rehabilitation 1999; 80: 462
467.
10 Fitzgerald S, Cooper R, Boninger M, Rentschler A. Comparison of
fatigue life for three types of manual wheelchairs. Archives of
Physical Medicine and Rehabilitation 2001; 82: 1484 1488.
11 Cooper R, Robertson R, Lawrence B, Heil T, Albright S, van
Sickle D, Gonzales J. Life-Cycles analysis of depot vs. rehabilita-
tion manual wheelchairs. Journal of Rehabilitation Research and
Development 1996; 33(1): 45 55.
12 Kaye H, Kang T, la Plante M. Mobility Device Use in the United
States. Disability Status Report 2000; 14 (National Institute on
Disability and Rehabilitation Research).
13 Hilbers P, White T. Effects of wheelchair design on metabolic and
heart rate responses during propulsion by persons with paraplegia.
Physical Therapy 1987; 67(9): 1355 1358.
14 Mossberg K, Rogers H. Standard vs. Lightweight wheelchairs: A
comparison of metabolic efficiency in treadmill propulsion.
Physical Therapy 2000; 80(5): 45.
15 Veeger D, van der Woude L, Rozendal R. The effect of rear wheel
camber in manual wheelchair propulsion. Journal of Rehabilitation
Research and Development 1989; 26(2): 37 46.
16 Harms M. Effect of wheelchair design on posture and comfort of
users. Physiotherapy 1990; 76(5): 266 271.
17 Shimada S, Robertson R, Bonninger M, Cooper R. Kinematic
characterization of wheelchair propulsion. Journal of Rehabilitation
Research and Development 1998; 35(2): 210 218.
18 Boninger M, Souza A, Cooper R, Fitagerald S, Koontz A, Fay B.
Propulsion patterns and pushrim biomechanics in manual wheel-
chair propulsion. Archives of Physical Medicine and Rehabilitation
2002; 83(5): 718 723.
19 Ruggles D, Cahalan T, An K. Biomechanics of wheelchair
propulsion by able bodied subjects. Archives of Physical Medicine
and Rehabilitation 1994; 75: 540 544.
20 van der Woude L, Botden E, Vriend I, Veeger D. Mechanical
advantage in wheelchar lever propulsion: effect on physical strain
and efficiency. Journal of Rehabilitation Research and Development
1997; 34(3): 286 294.
21 van der Woude L, Dallmeijer A, Janssen T, Veeger D. Alternative
modes of manual wheelchair ambulation: An overview. American
Journal of Physical Medicine and Rehabilitation 2001; 80(10): 765
777.
22 Parziale J. Standard vs Lightweight wheelchair propulsion in spinal
cord injured patients. American Journal of Physical Medicine and
Rehabilitation 1991; 70(2): 76 80.
23 Beekman C, Miller-Porter L, Schoneberger M. Energy cost of
propulsion in standard and ultralight wheelchairs in people with
spinal cord injuries. Physical Therapy 1999; 79(2): 146 158.
24 Rogers H, Brutscher M, Dufilho M, Kurz R. Standard vs.
ultralight wheelchairs: A comparison of functional mobility tasks.
Neurology Report 1998; 24(5): 2000.
25 Rodgers M, Keyser R, Rasch E, Gorman P, Russell P. Influence of
training on biomechanics of wheelchair propulsion. Journal of
Rehabilitation Research and Development 2001; 38(5): 505 511.
26 Dallmeijer A, van der Woude L, Hollander A, van As H. Physical
performance during rehabilitation in persons with spinal cord
injuries. Medicine and Science in Sports and Exercise 1999; 31(9):
1330 1335.
27 McLaurin C, Brubaker C. Biomechanics and the wheelchair.
Prosthetics and Orthotics International 1991; 15: 24 37.
28 Robertson R, Boninger M, Cooper R, Shimada S. Pushrim forces
and joint kinetics during wheelchair propulsion. Archives of
Physical Medicine and Rehabilitation 1996; 77: 856 864.
29 Patterson P, Draper S. Selected comparisons between experienced
and non-experienced individuals during manual wheelchair propul-
sion. Biomedical Sciences Instrumentation 1997; 33: 477 481.
30 de Groot S, Veeger H, Hollander A, van der Woude L. Wheelchair
propulsion technique and mechanical effeciency after 3 week
practice. Medicine and Science in Sports and Exercise 2002; 34(5):
756 766.
31 Richter W. The effect of seat position on manual wheelchair
propulsion biomechanics: a quasi-static, model-based approach.
Medical Engineering and Physics 2001; 23(10): 707 712.
A comparison of functional mobility in standard vs. ultralight wheelchairs
1087
Appendix 1
ID# _________
(1) Sex: Male & Female &
(2) Age: ____________________
(3) Have you been diagnosed with any of the following medical conditions or do you presently have any coexisting
medical conditions that might compromise your ability to propel a wheelchair with maximal effort?
Asthma Yes & No &
Uncontrolled Diabetes Yes & No &
Heart condition (i.e. murmur) Yes & No &
Neurological impairment Yes & No &
(i.e. balance or equilibrium problems)
Recent fracture or joint sprain Yes & No &
Limitation in joint range of motion Yes & No &
Back pain Yes & No &
Upper extremity tendonitis or overuse injury Yes & No &
Mental Disability (i.e. dementia) Yes & No &
Other (please list) Yes & No &
If you checked yes to any box, please give a brief explanation:
___________________________ ______________________________________________________________________
___________________________ ______________________________________________________________________
___________________________ ______________________________________________________________________
(4) Please estimate the amount of prior wheelchair experience you have had within the past year.
& 0 3 hours & 3 10 hours
& 10 20 hours &4 20 hours
(5) For female subjects only:
Are you pregnant? Yes & No &
H. Rogers et al.
1088
... Nonetheless, the standardization of clinical settings may help clients to better perform some tasks. For example, those requiring better lighting and clutter-free spaces rather than environment familiarity to successfully perform the task [23,24]. ...
... Research has shown that changes in the design of a wheelchair can result in positive changes in energy cost, joint kinematics and propulsion biomechanics [50]. For example, the high degree of adjustability of the ultra-light wheelchairs (UWC), namely the ability to adjust the seat height in relation to axle position as well as place the axle forward of the center of gravity of the user, has been shown to increase the mobility of the user by decreasing rolling resistance, increasing propulsion efficiency and smoothness, and preserving upper extremity integrity [24]. Cooper and his team also reported that the high degree of adjustability of the UWC can increase the mobility of the user and reduce the risk of secondary injury or disability [50][51][52]. ...
... The primary difference in the testing procedure was that the clinic was an unfamiliar, supportive environment, whereas the home was the familiar, naturalistic one. Hence, the actual performance differences were most likely due to environmental factors and that is consistent with previous literature [23,24,65]. For the total scores, and individual item scores the results of our study indicated that at pretest, the effect of the environment was neutral. ...
Book
The main objective of this study was to investigate associations, concordance and differences among self-report and performance-based measures, and reveal new factors associated with changes in wheelchair function. The Functioning Everyday with a Wheelchair (FEW); a self-report measure, the FEW-Capacity (FEW-C); a performance-based measure for the clinic, and the FEW-Performance (FEW-P) that measures clients’ skills in the home were the measures used in this study. The literature review in Chapters 1 and 2 synthesizes research studies that describe assessment of functioning with a wheelchair, and examine associations, concordance, and comparisons between the different methods used to assess everyday functional abilities of wheelchair users. Chapter 3 describes the associations among the three FEW instruments at pretest and posttest. Chapter 4 examines specific demographics, wheelchair characteristics, and functional status indicators associated with better and worse outcomes of the FEW instruments. Chapter 5 investigates the concordance of the FEW and the FEW-C with the criterion instrument, the FEW-P, and examines the differences between the FEW-C and the FEW-P at pretest and posttest. Finally, Chapter 6 provides a summary of all study objectives and results as well as implications for future research using the FEW instruments. Relevant literature yielded few studies that examined the associations and concordance between subjective and objective methods of assessment with wheelchair users. We conducted secondary analyses of data collected by Mills et al. (2002) and Schmeler (2005), in which participants were assessed with their current wheelchairs at pretest, and later at posttest after they received their new wheelchairs. The strength of the associations varied by time, item, and environment, and there was a stronger association between the three tools at the pretest when compared with the posttest, perhaps due to the familiarity of their current wheeled mobility device and their desire for a new wheelchair. Exhaustive CHAID analysis revealed new factors that were significantly associated with pretest to posttest changes in wheelchair function, and should therefore be assessed at pretest and targeted for intervention, namely, independence, number of physical assists, safety, and tasks related to Outdoor Mobility at pretest. Furthermore, for total scores, at pretest, there was no significant difference between the FEW-C and the FEW-P, whereas, at posttest, the Clinic total safety and quality scores were significantly better than the Home scores. We also found that the FEW-C was more concordant with the FEW-P compared to the FEW; therefore, clinicians may get a more accurate estimation of performance in the home from a clinic assessment compared to self-report. Clinically, the FEW tools provide complementary data which can contribute to clinical and research assessments of clients’ everyday functioning with their wheelchairs.
... Nonetheless, the standardization of clinical settings may help clients to better perform some tasks. For example, those requiring better lighting and clutter-free spaces rather than environment familiarity to successfully perform the task [23,24]. ...
... Research has shown that changes in the design of a wheelchair can result in positive changes in energy cost, joint kinematics and propulsion biomechanics [50]. For example, the high degree of adjustability of the ultra-light wheelchairs (UWC), namely the ability to adjust the seat height in relation to axle position as well as place the axle forward of the center of gravity of the user, has been shown to increase the mobility of the user by decreasing rolling resistance, increasing propulsion efficiency and smoothness, and preserving upper extremity integrity [24]. Cooper and his team also reported that the high degree of adjustability of the UWC can increase the mobility of the user and reduce the risk of secondary injury or disability [50][51][52]. ...
... The primary difference in the testing procedure was that the clinic was an unfamiliar, supportive environment, whereas the home was the familiar, naturalistic one. Hence, the actual performance differences were most likely due to environmental factors and that is consistent with previous literature [23,24,65]. For the total scores, and individual item scores the results of our study indicated that at pretest, the effect of the environment was neutral. ...
Preprint
The main objective of this study was to investigate associations, concordance and differences among self-report and performance-based measures, and reveal new factors associated with changes in wheelchair function. The Functioning Everyday with a Wheelchair (FEW); a self-report measure, the FEW-Capacity (FEW-C); a performance-based measure for the clinic, and the FEW-Performance (FEW-P) that measures clients’ skills in the home were the measures used in this study. The literature review in Chapters 1 and 2 synthesizes research studies that describe assessment of functioning with a wheelchair, and examine associations, concordance, and comparisons between the different methods used to assess everyday functional abilities of wheelchair users. Chapter 3 describes the associations among the three FEW instruments at pretest and posttest. Chapter 4 examines specific demographics, wheelchair characteristics, and functional status indicators associated with better and worse outcomes of the FEW instruments. Chapter 5 investigates the concordance of the FEW and the FEW-C with the criterion instrument, the FEW-P, and examines the differences between the FEW-C and the FEW-P at pretest and posttest. Finally, Chapter 6 provides a summary of all study objectives and results as well as implications for future research using the FEW instruments. Relevant literature yielded few studies that examined the associations and concordance between subjective and objective methods of assessment with wheelchair users. We conducted secondary analyses of data collected by Mills et al. (2002) and Schmeler (2005), in which participants were assessed with their current wheelchairs at pretest, and later at posttest after they received their new wheelchairs. The strength of the associations varied by time, item, and environment, and there was a stronger association between the three tools at the pretest when compared with the posttest, perhaps due to the familiarity of their current wheeled mobility device and their desire for a new wheelchair. Exhaustive CHAID analysis revealed new factors that were significantly associated with pretest to posttest changes in wheelchair function, and should therefore be assessed at pretest and targeted for intervention, namely, independence, number of physical assists, safety, and tasks related to Outdoor Mobility at pretest. Furthermore, for total scores, at pretest, there was no significant difference between the FEW-C and the FEW-P, whereas, at posttest, the Clinic total safety and quality scores were significantly better than the Home scores. We also found that the FEW-C was more concordant with the FEW-P compared to the FEW; therefore, clinicians may get a more accurate estimation of performance in the home from a clinic assessment compared to self-report. Clinically, the FEW tools provide complementary data which can contribute to clinical and research assessments of clients’ everyday functioning with their wheelchairs.
... In-home performance (FEW-P) was selected as the criterion method because 1) the home is the environment where persons usually perform their routine activities of daily living and either offers the most support or challenges functional performance, 2) the home is a familiar real-world environment where persons wish to remain [3]. ...
... The primary difference in the testing procedure was that the clinic was an unfamiliar, supportive environment, whereas the home was the familiar, naturalistic one. Hence, the actual performance differences were most likely due to environmental factors and that is consistent with previous literature [2,3,11]. For the total scores, and individual item scores the results of our study indicated that at pretest, the effect of the environment was neutral. ...
Article
Objective: the main objective of this study was to investigate concordance and differences among self-report and performance-based measures for wheelchair users. Method: the Functioning Everyday with a Wheelchair (FEW); a self-report measure, the FEW-Capacity (FEW-C); a performance-based measure for the clinic, and the FEW-Performance (FEW-P) that measures clients’ skills in the home were the measures used in this study. We examined the concordance of the FEW and the FEW-C with the FEW-P as the criterion measure, and investigated the differences between the FEW-C and the FEW-P at pretest and posttest following the provision of a new wheeled mobility and seating device. Results: our results suggested that the FEW-C was most concordant with the FEW-P for majority of the items compared to the FEW. At both pretest and posttest, for most of the tasks, the FEW-C and FEW-P were comparable suggesting that the environment may have a neutral effect. However, at posttest, the clients’ safety scores for the Outdoor Mobility task and the clients’ quality scores for the Personal Care task improved significantly suggesting that the standard supportive environment of the clinic may have enabling effect on activity performance. Conclusion: Clinically, rehabilitation clinicians may get a more accurate estimation of functional performance in the home from a clinic assessment, and they are cautioned that the inclusion of self-report assessment and data obtained from clients’ perceptions may be discrepant with actual performance. We also concluded that the impact of the environment on activity performance of wheelchair users can be neutral or enabling depending on time of assessment and tasks being assessed.
... Wheelchairs (UWC), namely the ability to adjust the seat height in relation to axle position as well as place the axle forward of the center of gravity of the user, has been shown to increase the mobility of the user by decreasing rolling resistance, increasing propulsion efficiency and smoothness, and preserving upper extremity integrity [8]. Cooper and his team also reported that the high degree of adjustability of the UWC can increase the mobility of the user and reduce the risk of secondary injury or disability [7,9,10]. ...
... Also, even though no data were missing, surprisingly, no demographics were indicated and only one wheelchair characteristic was included in the Exhaustive CHAID analyses, namely, whether the participants had a removable arm support at pretest. This finding is not consistent with the current body of literature which reports that demographic variables such as age, race, employment status, and type of wheelchair can contribute to different functional performance outcomes [7][8][9][10][11]28]. This finding warrants further investigation to examine the dynamic interaction between the various demographics and wheelchair characteristics and change scores of the FEW, FEW-C, and FEW-P tools that measure functional performance of wheelchair users. ...
Article
Objective: The main objective of this study was to explore demographics, wheelchair characteristics, and functional status indicators associated with changes in perceptions and functional performance of wheelchair users. Method: Nineteen wheelchair users were selected for this exploratory study. Utilizing Exhaustive Chi-Squared Automatic Interaction Detector (CHAID) analysis, seven models were generated to examine specific demographics, wheelchair characteristics, and functional status indicators associated with pretest to posttest change scores in perceptions and performance of everyday tasks over time of three target variables. Validation of the models generated by Exhaustive CHAID analyses was conducted through the n-fold cross-validation procedure. The Functioning Everyday with a Wheelchair (FEW), the FEW-Capacity (FEW-C), and the FEW-Performance (FEW-P) were the measures used in this study. Results: The means for the change score were larger for the FEW (1.08 ± 0.59) followed by the FEW-C (0.69 ± 0.63), and then the FEW-P (0.33 ± 0.45). Most of the factors identified in each model were derived from the pretest. Our study explored factors that were significantly associated with change scores of the FEW tools. Independence, number of physical assists, safety, and tasks related to Outdoor Mobility at pretest were the functional status indicators found to be of greatest importance and significantly associated with changes in perceptions and performance of everyday tasks over time in our models. For all analyses, the values of the Risk Estimate for the Risk Statistics and Cross-validation were close with relatively small differences, suggesting strong and reasonable confidence in the validity of the seven models. Conclusion: This study may suggest specific focus areas for assessment and intervention and may highlight the importance of some factors that influence changes in functional performance among clients who have been referred for, and prescribed, a wheeled mobility device.
... The frame is usually made of aluminum, titanium, manganese, and graphite that weighed half of steel-made wheelchairs [69]. In comparison between lightweight and standard wheelchairs, the prior one presented a reduction in the frequency of vibrations in parallel with increasing frequency of casters' floor detaching [70]. Lightweight wheelchairs can reduce the pain in the upper extremities effectively in users having spinal cord problems [71]. ...
Chapter
Fall is one of the leading causes of fatal and nonfatal injuries in older adults. Fall may lead to different kinds of harms such as physical and cognitive problems, psychological impairments or even death. More than 30% of older adults aged 65 and above experience fall every year. As people age, their ability in maintaining balance reduces, causing an increase in the incidence of fall. There are many prevention strategies and interventions presented to minimize the incidence of fall over the last decades in terms of exercising, improving fall-related knowledge, modifying home facilities, and assistive devices. This chapter presents a review of mobility-assistive devices including canes, wheelchairs, exoskeletons, and walkers for mobility-impaired people. In particular, the chapter also focuses on smart walking devices and highlights their features and subsystems with the aim to investigate their limitations.
... Given that the FEW is a self-report measure of functional performance and there are ongoing questions related to self-report measures and whether self-reported measures are associated with performance-based measures [3,22], the primary purpose of this study was to examine the associations among the self-report (FEW), and the performance-based (FEW-C, FEW-P) measures at pretest and posttest, before and after the provision of a new wheeled mobility and seating device provided by a qualified interdisciplinary team of clinicians. ...
Article
Objective: The main objective of this study was to investigate associations of self-report and performance-based measures of functional performance for wheelchair users. Method: The Functioning Everyday with a Wheelchair (FEW); a self-report measure, the FEW-Capacity (FEW-C); a performance-based measure for the clinic, and the FEW-Performance (FEW-P); a performance-based measure that measures clients’ skills in the home were the measures used in this study. The current study examines the associations among the different methods used with the FEW, FEW-C and FEW-P at pretest when participants used their customary wheel chairs and post test when participants used their new wheelchairs. Results: Our hypothesis that there would be a stronger association between the FEW, FEW-C, and FEW-P at the pretest than the posttest due to the familiarity with the wheeled mobility device was partially confirmed. Overall, the relationships among the self-report (FEW) and the performance-based (FEW-C, FEW-P) total independence scores were significantly associated at both pretest and posttest as were the relationships between the two performance-based tools. However, these significant relationships were stronger at the pretest compared to the posttest. Conclusion: Our hypothesis that there would be a stronger association between the FEW, FEW-C and FEW-P at the pretest when compared with the posttest was accepted for the total scores but was only partially confirmed for the individual items of these tools. Our findings indicate that both methods (self-report and performance-based) can yield useful information, may have potential roles in clinical and research settings, and may have complementary relationships.
... Both subjective and objective methods are useful and are complementary. Decisions on which of these assessment methods to use are based on the purpose of the evaluation and, clinically, a combination of methods is typically used [21].Furthermore, wheelchair assessments can be categorized into three different settings: real (daily environments; home, workplace), controlled (clinical setting and obstacle course), or virtual environments (computerized driving simulators) [22]. Prior research on persons with disabilities and wheelchair users has documented that these different settings could be more or less realistic and could be more or less facilitative/challenging. ...
Article
Wheelchairs are enablers of community participation and are used to enhance function, to improve independence, and to enable a person to successfully live at home and in the community. It is estimated that 70 million people require wheelchairs worldwide (World Health Organization [WHO], 2017). The most current available data on persons who use wheelchairs comes from the 2008 National Survey of Income and Program Participation, which indicated that there were about 56.7 million people with disabilities (number increased by 2.2 million since 2005) and 3.6 million wheelchair/scooter users in the United States (USA) in 2010. Despite the vital role of wheelchairs, the substantial number of wheelchair users and the increasing demand on providers to meet their needs, there is currently a lack of comprehensive outcome measures that focus on everyday functioning with a wheelchair. Therefore, appropriate outcome measurements are needed.
... While UW were originally developed for sports [11,14], clinicians are increasingly recommending them as a primary source of mobility for independent, active users who can benefit from their responsive wheeling performance throughout the day [12][13][14]. Research points to numerous benefits of UW including improved maneuverability, propulsion mechanics and mobility [15]. Current clinical guidelines recommend UW for the preservation of upper limb function [16]. ...
Article
A “kneeling” ultralight wheelchair prototype has been developed that allows users to adjust seat position “on the fly” for different activities throughout the day. The wheelchair includes independent adjustment functions for rear seat height, front seat height (“kneeling”) and backrest angle. Aim: This work aimed to gather feedback about the wheelchair’s functionality and performance through end user evaluation trials. Methods: Eight manual wheelchair users evaluated the prototype Kneeling Wheelchair for a range of activities. User perspectives on parameters such as usability, comfort, stability and effectiveness were obtained through both open-ended and Likert-scale rating questions. Results: Results indicate several potential benefits of the adjustment functions of the Kneeling Wheelchair. Rear seat height adjustment may facilitate a number of activities of daily living, as well as provide benefits for comfort and social interactions. Back rest adjustment may increase comfort and stability on slopes. Front seat height adjustment may be beneficial for transfers and conducting sustained low-to-the-ground activities. While benefits of this adjustment function were described by many participants, some struggled with usability of the kneeling mechanism and rated this function less favourably than the other two. Conclusion: The findings of this study will inform future iterations of the Kneeling Wheelchair design and may spur future developments in wheeled mobility. In the long-term, it is anticipated that novel wheelchair solutions, such as the one described in this paper, may support improved health, quality of life and community participation for people with mobility impairments. • Implications for rehabilitation • Wheelchairs that allow users to easily adjust seat and backrest position “on the fly” to better suit different tasks throughout the day may provide benefits such as facilitating activities of daily living. • A front seat height adjustment feature on a new wheelchair prototype may be beneficial for transfers and conducting sustained low-to-the ground activities. • End user evaluations can provide valuable insight to direct future design modifications and innovation.
Article
Background: The clinimetric properties of the Wheelchair Propulsion Test (WPT) have not been developed thoroughly. Objective: To determine inter-rater reliability and reference values for the Wheelchair Propulsion Test (WPT) for active wheelchair users and to compare WPT performance between various types of manual wheelchairs at different paces. Methods: This was a cross-sectional, descriptive study. Participants propelled a manual wheelchair 10 m while time and the number of pushes were recorded. Trials were performed in three different manual wheelchairs (a lightweight wheelchair (LW), an ultralightweight wheelchair (ULW), and the participant's personal, customized wheelchair) at a comfortable pace and a fast pace. Results: The ICC values ranged from 0.861 to 0.999 for both speed and number of pushes. Comfortable wheelchair propulsion speed ranged from 1.51 (0.31) m/s to 1.65 (0.33) m/s depending on the wheelchair utilized. Across both pace conditions, participants were significantly faster when using their personal wheelchair compared to the ULW (P < 0.001) and LW (P < 0.001). Push frequency was significantly greater during the fast pace condition compared to the comfortable pace condition (P < 0.001). Conclusions: Reference values for the WPT in active wheelchair users have been identified. Participants who utilize their personal wheelchair demonstrate faster wheelchair propulsion speeds complemented by greater push frequencies.
Article
Manual wheelchair (MWC) users face a variety of obstacles limiting their participation. Different MWC models and new add-on components intended to improve propulsion may impact users’ function and participation, although there is a lack of research on this topic. The aims of this study were to: 1) identify MWC propelling aids (PA) that are reported in the literature; 2) classify the outcomes used to evaluate the influence of PA according to the International Classification of Functioning, Disability and Health (ICF); and 3) summarize evidence for the influence of PA. A scoping review was conducted in 2017 using Pubmed, Medline, Embase, CINAHL, Compendex, IEEE Xplore, RESNA and ISS proceedings, Google, and Google Scholar. The content of each manuscript was assessed by two independent reviewers. A total of 28 PA (19 human-powered; 9 power-assisted) were identified from 163 manuscripts. The three most cited ICF subdomains were “Activity & Participation” (n = 125), “Body Function” (n = 100), and “Personal Factors” (n = 55). The findings suggest an overall positive influence of PA on various ICF domains/subdomains, but initial findings should be interpreted with caution. Confirmation of the effect and safety of PA requires higher levels of evidence.
Article
Full-text available
Wheelchair biomechanics involves the study of how a wheelchair user imparts power to the wheels to achieve mobility. Because a wheelchair can coast, power input need not be continuous, but each power strike can be followed by a period of recovery, with the stroking frequency depending on user preferences and the coasting characteristics of the wheelchair. The latter is described in terms of rolling resistance, wind resistance and the slope of the surface. From these three factors the power required to propel the wheelchair is determined, and must be matched by the power output of the user. The efficiency of propulsion is the ratio of this power output to the metabolic cost and is typically in the order of 5% in normal use. The features required in a wheelchair depend upon user characteristics and intended activities. The ideal wheelchair for an individual will have the features that closely match these characteristics and activities. Thus prescription is not just choosing a wheelchair, but choosing the components of the wheelchair that best serve the intended purpose. In this paper, each component is examined for available options and how these options effect the performance of the wheelchair for the individual. The components include wheels, tyres, castors, frames, bearings, materials, construction details, seats, backrests, armrests, foot and legrests, headrests, wheel locks, running brakes, handrims, levers, accessories, adjustments and detachable parts. Each component is considered in relation to performance characteristics including rolling resistance, versatility, weight, comfort, stability, maneouvrability, transfer, stowage, durability and maintenance. Where they exist, wheelchair standards are referred to as a source of information regarding these characteristics.
Article
Full-text available
To study the effect of seat height on the cardiorespiratory system and kinematics in handrim wheelchair ambulation, nine non-wheelchair users participated in a wheelchair exercise experiment on a motor-driven treadmill. The subjects conducted five progressive exercise tests. After an initial try-out test, four tests were performed at different standardized seat heights of 100, 120, 140, and 160 degrees elbow extension (subject sitting erect, hands on the rim in top-dead-center = 12.00 hrs; full extension = 180 degrees). Each test consisted of four 3-minute exercise blocks at speeds of respectively 0.55, 0.83, 1.11, and 1.39 m.s-1 (2-5 km.hr-1). Analysis of variance revealed significant effects of seat height (P less than 0.05) on gross mechanical efficiency (ME), oxygen cost, push range, and push duration, and on the ranges of motion in the different arm segments and trunk. Mean ME appeared higher at the lower seat heights of 100 and 120 degrees elbow extension. This is reflected in an enhanced oxygen consumption at seat heights of 140 and 160 degrees elbow extension. Simultaneously, the push range showed a 15 to 20 degree decrease with increasing seat height, which is reflected in a decreased push duration. In the push phase, decreases in retroflexion and abduction/adduction of the upper arm were seen. The trunk shifted further forward, and the motion range in the elbow joint shifted to extension with increasing seat height. No shifts in minimum and maximum angular velocities were seen with increasing seat height. The results showed an interrelationship between wheelchair seat height and both cardiorespiratory and kinematic parameters. With respect to the cardiorespiratory system, the optimization of the wheelchair geometry, based on functional characteristics of the user, appears beneficial.
Article
Full-text available
Eight nonimpaired subjects participated in a wheelchair exercise test using a motor-driven treadmill in order to study the effect of rear wheel camber on wheelchair ambulation. The test consisted of four runs with rear wheels in 0, 3, 6, and 9 degrees camber at four speed steps of 2, 3, 4, and 5 km/hr. There were no significant effects upon oxygen cost, heart rate, and mechanical efficiency. The kinematic parameters of push time, push angle, and abduction showed differences between 3 and 6 degrees camber. The relationship between the findings, using surface EMG results for six shoulder muscles, is discussed. For one subject, data were extended to study the angular velocities of shoulder and elbow.
Article
This study examines three different types (depot, lightweight, ultralight) of manual wheelchairs that have been tested to fatigue according to ISO standards. Results indicate that ultralight wheelchairs were significantly better than lightweight and depot with regard to fatigue life
Article
The canvas sling seat and backrest incorporated into a conventional wheelchair provide a seating system which fails short of many basic ergonomic requirements, which may compromise the comfort, health and level of dependency of the user. The high incidence of back pain among able-bodied people gives rise to much concern. Yet although there are indications that a similar proportion suffer, back pain in the disabled population receives less specific attention. Two prospective studies were undertaken involving a total of 58 subjects. The first evaluated the effects of wheelchair design on posture and the second looked at the effects that this had on the comfort of the user. Posture was recorded using a technique for measuring spinal curves, and data on the comfort of each seat were collected by questionnaire. The studies evaluated three different seating systems. The first was that of a conventional model 8BL wheelchair; the second and third were experimental rigs incorporated into an 8BL frame. One rig had cushions chamfered to fit the concavities of the canvas seat and backrest and the second had a rigid base on which was mounted cushioning material. The unmodified 8BL was shown to encourage a kyphotic posture and caused discomfort in both able-bodied and disabled subjects especially in the neck and back. The two experimental rigs promoted an acceptable degree of lordosis and, although both proved more comfortable than the canvas seat, of the two the hard-based seat was preferred.
Article
Objective: This study provides data for clinicians and wheelchair users to compare the durability, stability, and cost effectiveness of three different lightweight wheelchair models: the Everest & Jennings EZ Lite, the Invacare Rolls 2000, and the Quickie Designs Breezy. A second objective was to compare the results from this study to those published for ultralight and institutional depot wheelchairs.Design: Randomized standards testing of three wheelchair models from each manufacturer (nine wheelchairs total).Results: There were no significant differences (p > .05) in fatigue life, life-cycle cost, or static stability between the three models of lightweight wheelchairs (ie, EZ Lite, Rolls 2000, or Breezy). There were, however, significant differences (p < .05) in fatigue life among the lightweight wheelchairs of this study and the published results for ultralight rehabilitation wheelchairs and for depot wheelchairs. The lightweight wheelchairs had an average fatigue life greater than the depot wheelchairs but less than the rehabilitation wheelchairs. A depot-type wheelchair was defined as a manual wheelchair designed for hospital or institutional use. A lightweight wheelchair was defined as a manual wheelchair with minimal adjustments designed for individual or institutional use. An ultralight rehabilitation wheelchair was defined as a manual wheelchair designed for an individual's use as a long-term mobility aid.Conclusion: The three models of lightweight wheelchairs tested are substantially similar and their fatigue lives are significantly (p < .05) lower than rehabilitation wheelchairs. Ultralight rehabilitation wheelchairs are the most cost effective over the life of the wheelchair, costing 3.4 times less (dollars per life cycle) than depot wheelchairs, and 2.3 times less (dollars per life cycle) than the lightweight wheelchairs tested in this study.
Article
The pattern of propulsion was investigated for five male paraplegics in six seating positions. The positions consisted of a combination of three horizontal rear-wheel positions at two seating heights on a single-purpose-built racing wheelchair. To simulate wheelchair propulsion in the laboratory, the wheelchair was mounted on high rotational inertia rollers. For three trials at each seating position, the subjects propelled the designed wheelchair at 60 percent of their maximal speed, which was determined at the beginning of the test session. At each trial, the propulsion technique of the subject was filmed at 50 Hz with a high-speed camera for one cycle, and the raw electromyographic (EMG) signal of the biceps, brachii, triceps brachii, pectoralis major, deltoid anterior, and deltoid posterior muscles were simultaneously recorded for three consecutive cycles. The digitized film data were used to compute the angular kinematics of the upper body, while the EMG signals were processed to yield the linear envelope (LE EMG) and the integrated EMG (IEMG) of each muscle. The kinematic analysis revealed that the joint motions of the upper limbs were smoother for the Low positions-since they reached extension in a sequence (wrist, shoulder, and elbow), when compared to the High positions. Also, the elbow angular velocity slopes were found to be less abrupt for the Backward-Low position. It was observed that in lowering the seat position, less IEMG was recorded and the degrees of contact were lengthened. Among the seat positions evaluated, the Backward-Low position had the lowest overall IEMG and the Middle-Low position had the lowest pushing frequency. It was found that a change in seat position caused more variation in the IEMG for the triceps brachii, pectoralis major, and deltoid posterior. The trunk angular momentum was not found to be affected by a change in seat position which may be related to the variability among the subject's technique of propulsion or to a posture compensation.
Article
Twenty-six male SCI subjects (six quadriplegics, eight "high paraplegics," and 12 "low paraplegics") propelled both standard and lightweight wheelchairs at a "sprint pace" (Sp) for 400 feet, and at a "duration pace" (Du) for four continuous minutes. Pulse, blood pressure and respirations were measured before and after each trial, and V was calculated. Appropriate training and rest periods were given; order of wheelchair testing was randomized. A questionnaire was later administered. Variations in pulse, systolic blood pressure, and respirations were significant between myelopathic levels (P less than 0.01), but were not affected by the type of wheelchair used. Quadriplegic V was less (P less than 0.01) than that of either paraplegic group for Sp and Du trials; for Sp, lightweight wheelchair V is faster (P less than 0.01) than standard wheelchair V for all groups.