Contribution of limb momentum to power transfer in athletic wheelchair pushing
Introduction
One way to improve athletic wheelchair racing speed is to increase energy transfer to the wheelchair. Several variables may affect energy transfer, ranging from equipment design (Slowik and Neptune, 2013, Costa et al., 2009, Jacobson, 1995, MacLeish et al., 1993), athlete anthropometry, handicap and neuromuscular capabilities (Vanlandewijck et al., 2011), to the specific motor control strategy chosen to accomplish the task (Vegter et al., 2015, Rankin et al., 2012, Goosey et al., 1997). In fact, upper limb configuration adopted by an athlete while pushing directly influences a number of limb characteristics likely involved in energy transfer to the wheelchair, including: force production capability, hand stiffness (Rancourt and Hogan, 2009), dexterity and manipulating ability (Yoshikawa, 1990) i.e. its ability to maneuver the hand in space. In addition, athletes are free to choose a specific pushing range, contacting the pushrim at a given attack angle, to further leave it at the release angle, after a given wheel rotation. Specific reasons for selecting one pushing range over another are not yet well understood. For instance, athletes could choose a pushing range to maximize energy transfer to the wheelchair, or to simply reduce muscle fatigue.
Energy transfer to the wheelchair can be achieved in two ways during the push phase, defined as the time period while the hand contacts the pushrim. Firstly, athletes can transfer energy to the wheelchair through muscular exertion during the push phase. Secondly, athletes may take advantage of their upper limb momentum, both angular and linear. Indeed, considerable limb momentum can be accumulated during the recovery phase, defined as the time period while the hand does not contact the pushrim. This momentum can be exploited during the push phase to exert forces on the pushrim. Currently, the contribution of limb momentum to wheelchair pushing is unknown. This question is relevant since it may provide new insights on training strategies that may enhance performance or for prevention of musculo-skeletal injuries (Sosnoff et al., 2015, Boninger et al., 2002).
The purpose of this study was to estimate the potential contribution of upper limb momentum to pushing by computing the power transferred to the wheelchair by a passive, four-bar linkage during a single push. Pushing contribution was compared to the actual power produced by two T54 Paralympic athletes, seated in their own wheelchairs fixed on a high performance ergometer.
Section snippets
Origin of upper limb momentum
At the end of the recovery phase, the upper limb is quickly extended forward and downward to contact the pushrim at an attack angle θin from the horizontal (Fig. 1, adapted from Vanlandewijck et al., 2001). During that time period, the overall angular momentum HO of the wheelchair-athlete-roller system, about any fixed point O in space (e.g. wheel contact point with ground when rolling on a track or alternatively, rear wheel axle when the wheelchair is on an ergometer), is progressively
Results
Experimental data from the all-out test showed that the time-dependent velocity profile followed an exponential curve similar to data previously published (Masson et al., 2013), reaching a maximal speed at the end of the acceleration phase, after which the velocity slowly decreased over time in a linear-like fashion, during the deceleration phase or fatigue phase. For athlete 1, instantaneous power transferred to the wheel during the all-out test initially peaked at about 1500 W, to
Discussion
Contribution of limb momentum was estimated by simulating the time response of a simplified dynamic model fitted to two T54 Paralympic racing wheelchair athletes. Although previous studies made use of sophisticated musculo-skeletal models to predict upper limb-wheelchair time response (Vegter et al., 2015, Slowik and Neptune, 2013, Rankin et al., 2012), a simpler model was preferred to reduce the number of model parameters, along with three fundamental assumptions.
Firstly, the system response
Conclusions
A forward dynamic passive model of the upper limb/wheelchair system was developed and showed that upper limb momentum alone can transfer as much as 40 J to a wheelchair moving at 10 m/s, at each push cycle. The actual amount of energy depends on a number of parameters, including wheelchair speed and pushing range. Experimental results show that both muscle exertion and upper limb momentum likely contribute to pushing at high speeds, but determining their relative contribution is not trivial.
Conflict of interest statement
None of the authors have conflict of interest regarding the paper.
Acknowledgments
This work was supported by the Natural Sciences and Engineering Research Council of Canada (Grant no. 155048) and the Institut National du Sport de Montréal. We are grateful to all Canadian Paralympic athletes that contributed to our understanding of the pushing task in athletic wheelchair racing.
References (20)
- et al.
Propulsion patterns and pushrim biomechanics in manual wheelchair propulsion
Arch. Phys. Med. Rehabil.
(2002) - et al.
The influence of wheelchair propulsion technique on upper extremity muscle demand: a simulation study
Clin. Biomech.
(2012) - et al.
A theoretical analysis of the influence of wheelchair seat position on upper extremity demand
Clin. Biomech.
(2013) Preservation of upper limb function following spinal cord injury: a clinical practice guideline for health-care professionals
J. Spinal Cord. Med.
(2005)- et al.
Case study: effect of handrim diameter on performance in a paralympic wheelchair athlete
Adapt. Phys. Act. Quat.
(2009) Influence of mass on the speed of wheelchair racing
Sports Eng.
(2009)- et al.
A kinematic analysis of wheelchair propulsion techniques in senior male, senior Female, and junior Male Athletes
Adapt. Phys. Act. Quat.
(1997) An evaluation of wheelchair racing hand gear
(1995)- et al.
Design of a composite monocoque frame racing wheelchair
J. Rehabil. Res. Dev.
(1993) - Masson, G., Lessard, J.-L., Smeesters, C., Berrigan, F., Langelier, E., Rancourt, D., 2013. Performance enhancement...
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