This study aimed to compare VO2max scores in wheelchair athletes using an upper-body ergometer and a new wheelchair ergometer prototype. Ten male wheelchair basketball players performed VO2max tests on both ergometers. No significant differences were found between the ergometers, though there was a trend toward higher scores on the wheelchair prototype. Data screening removed outliers due to large differences in body mass. While inconclusive, the study provided insights to improve the wheelchair ergometer prototype for better testing wheelchair athletes' aerobic fitness.

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Glaser, R. M., & Sawka, M. N. (1980). Physiological Responses to Maximal Effort Wheelchair
and Arm Crank Ergometry. Journal of Applied Physiology, 48(6), 1060-1064.
Goosey-Tolfrey, V. (2010). Wheelchair Sport; A complete guide for athletes, coaches, and
teachers. Champaign, IL: Human Kinetics.
Haisma, J. A., L H V Van Der Woude, Stam, H. J., Bergen, M. P., Sluis, T. A., & Bussmann, J. B.
(2006). Physical capacity in wheelchair-dependent persons with a spinal cord injury: A
critical review of the literature. Spinal Cord, 44(11), 642-652.
Knechtle, B., & Kopfli, W. (2001). Treadmill Exercise Testing with Increasing Inclination as
Exercise Protocol for Wheelchair Athletes. International Medical Society of Paraplegia,
39, 633-636. Retrieved February 22, 2016.
Köklü, Y., Alemdaroğlu, U., Koçak, F., Erol, A., & Fındıkoğlu, G. (2011). Comparison of Chosen
Physical Fitness Characteristics of Turkish Professional Basketball Players by Division
and Playing Position. Journal of Human Kinetics, 30(-1).
Lakomy, H. K., Campbell, I., & Williams, C. (1987). Treadmill performance and selected
physiological characteristics of wheelchair athletes. British Journal of Sports Medicine,
21(3), 130-133.
Larry, K. W., Costill, D. L., & J. H. (2015). Physiology of sport and exercise (6th ed.).
Champaign, IL: Human Kinetics.
Mason, B. S., & Van Der Woude, L. H. (2012). Effects of Wheel and Hand-Rim Size on
Submaximal Propulsion in Wheelchair Athletes. Medicine & Science in Sports &
Exercise,44(1), 126-134. Retrieved February 20, 2016.
Price, D. T., MD, Davidoff, R., MBBCh, & Balady, G. J., MD. (2000). Comparison of
Cardiovascular Adaptations to Long-Term Arm and Leg Exercise in Wheelchair
Athletes Versus Long-Distance Runners. The American Journal of Cardiology, 85, 996-1001.
Retrieved February 20, 2016.
SOUTHWESTM I N N E S O T A S T A T E U N I V E R S I T Y
VO2max Scores using an Upper-Body Ergometer and Wheelchair
Ergometer Prototype in Wheelchair Athletes
Aaron Madson and Shawn Jensen
Southwest Minnesota State University
Discussion
References
Abstract
Introduction
Acknowledgement
The standard measure of aerobic fitness is VO2max. Aerobic fitness is an
important determinant of sport performance, including wheelchair
basketball players. Testing aerobic fitness in wheelchair athletes is difficult
due to equipment limitations. In order to more effectively determine VO2max
in wheelchair athletes, sport-specific testing equipment needs to be used.
However, these are currently not available on the market. The purpose of
this study is to determine if there is a difference in VO2max scores in
wheelchair athletes using two different ergometers: an upper-body crank
ergometer and a wheelchair ergometer prototype. Our study will explore
three major points: 1) if testing specificity will positively affect VO2max
scores for the wheelchair ergometer prototype, 2) to determine a maximal
aerobic test protocol for the wheelchair ergometer prototype, 3) to find
faults in the current prototype in order to effectively modify the prototype.
We hypothesized the wheelchair ergometer prototype VO2max scores will
be higher than those of the upper body ergometer machine, due to the
relation of sport-specific movement. No differences were detected between
ergometers, the upper-body arm crank mean was 28.09 ± 5.39 ml/kg/min,
while the wheelchair ergometer prototype mean was 32.33 ± 6.49
ml/kg/min. After removing outliers, we saw a trend for increased VO2max
values from the upper-body crank ergometer to the wheelchair ergometer
prototype.
10 male wheelchair basketball athletes from the campus of Southwest Minnesota State University were recruited for this study. They were
randomly placed into two groups, one beginning the VO2max tests on the upper-body ergometer and finishing with the wheelchair ergometer prototype,
and the other beginning on the wheelchair ergometer prototype and ending on the upper-body ergometer. A seven day recovery period was allowed
between each test. The data was analyzed in SPSS using a one-way ANOVA.
Because of convenience and the athlete’s comfort and familiarity, each subject performed the tests in their own basketball chairs. Each subject
was fitted with a Polar heart rate monitor before being rolled into place at each apparatus. They were then fitted with a headset and mouthpiece then
attached to the measurement system. The data was collected by using a PARVO Medics TrueOne2400 metabolic measurement system, with the
subjects performing the tests on an upper body ergometer machine and a wheelchair ergometer prototype.
We began the test on the upper-body ergometer at 25 Watts, increasing in increments of 25 Watts every two minutes until exhaustion (figure 1).
The wheelchair ergometer prototype was set at four “clicks” of initial resistance, and increased by two clicks every two minutes until maximum resistance
was reached. The quantification of a single “click” on magnetic resistance has not been performed for this prototype. The athlete then completed either
one last two minute stage on the highest resistance while pushing at maximal effort, or pushed for one minute at 90%, 95%, and complete maximum
effort to complete the test (figure 2).
In the sport of basketball, an athlete’s aerobic endurance is a
key determinant of an athlete’s stamina in late-game situations. This
is the case, not just for able-body basketball players, but wheelchair
basketball players as well. VO2max scores are the standard way to
determine an athlete’s aerobic fitness.
Researchers and coaches of wheelchair basketball athletes
face a difficult obstacle when testing VO2max in such athletes, because
either the athlete uses a machine that prevents them from moving in a
sport-specific movement, or they have to perform the test on an
impractical apparatus (Knechtle, Price). Examples of these would
include an upper-body ergometer, placing a wheelchair on an actual
treadmill, or a wheelchair ergometer that only places resistance on
one wheel (Knechtle, Glaser, Martel).
During incremental aerobic exercise, able-body athletes are
able to increase exercise intensity until exhaustion, when maximum
oxygen uptake is occurring. During upper body exercise, this is not
the case. Local muscle fatigue begins to set in before maximum
oxygen uptake occurs, in which case a VO2peak is used (Goosey-
Tolfrey 2010).
These obstacles led to the development of the current
wheelchair ergometer prototype, which allows the wheelchair athletes
to incorporate sport-specific pushing movements to their aerobic
training, and to minimize local muscle fatigue in order to find true
VO2max values for wheelchair athletes. The wheelchair ergometer
makes use of more sport-specific movement, which means training on
it would increase wheelchair athletes’ aerobic capacity more so than
the upper-body crank ergometer would (Larry). They would also be
more familiar with the pushing motion, which should lessen the
localized fatigue that is typically seen when testing wheelchair
athletes.
VO2max values for wheelchair users who are non-athletes is
around 1.51 l/min (Haisma), while values for wheelchair athletes is
around 1.82 l/min (Lakomy). These differ from able-body basketball
players, who average 2.55 l/min (Köklü). The VO2max values are
smaller for wheelchair athletes because not as much muscle mass is
needed to push than is needed for able-body athletes to run.
Thank you to Derek Klinkner and the wheelchair basketball team for
participating in our study. Also thank you to Jeffrey W. Bell, Ph.D. for his
leadership and his consistent effort. Thank you also to Demi Rorvick for
her assistance with testing.
Materials and Methods
Data screening showed that there was not a normal distribution
among the subjects. The outliers were identified and removed from
statistical analysis. The outliers were determined based on body mass
and were removed because their average weight was 290 pounds,
whereas the rest of the subjects’ average weight was 149 pounds. This
difference in weight negatively impacted their performance on the
wheelchair ergometer because the magnet that controls the resistance
was not strong enough to account for the difference in body mass.
obtained the desired response.
The data we obtained showed no statistical significance between
the two ergometers (28.09 ± 5.39 ml/kg/min vs 32.33 ± 6.49 ml/kg/min,
p = 0.39, figure 3). However, there was a trend for higher scores on the
wheelchair ergometer than on the upper-body crank ergometer which is
shown by individual participant results in figure 4.
Results
Figure 1. Subject performing VO2max test on
upper-body crank ergometer.
Figure 2. Subject performing VO2max test on
wheelchair ergometer prototype.
This study was underpowered, possibly leading to the lack of
statistical significance. Post-hoc power analysis showed that in order to
detect a change of 0.3 liters +/- 0.68 , with a level of significance of 0.05
and an upper limit of 0.8, we would need 81 total subjects. We saw a
bigger difference in some subjects because their specific physical
disability inhibited their performance. For example, a subject with spina
bifida wouldn’t improve as much from the arm-crank to the wheelchair
ergometer as an amputee subject would. Specific disability populations
need to be tested in the future.
While the data obtained showed no statistical significance, we
were able to find mechanical changes needed to improve the prototype.
These changes include installing a more powerful magnet for resistance,
installing a dashboard to monitor instantaneous power outputs, and
some other mechanical details to help the loading of subjects onto the
roller. This study indicated that future development of the prototype may
be necessary to find differences in smaller samples.
Figure 4. Individual subject VO2max values on
each apparatus presented as actual score.
Outliers have been removed.
Figure 3. Oxygen consumption presented as means
with standard error for each apparatus. Outliers
have been removed.