Simulation analysis of pushing motion during short distance dash in wheelchair tennis

Abstract

Wheelchair sports have an important role as a tool of rehabilitation for people with physical disabilities in lower limbs, and have been a driving force for innovation in wheelchair technology and practice as well. In wheelchair tennis, it is important to evaluate the pushing motion by players as well as the performance of the wheelchair when pushing. The objective of this study was to construct a comprehensive simulation model which was capable of evaluating the design parameters of a wheelchair as well as the pushing motion by a player in wheelchair tennis, and to investigate the effect of seat height of a wheelchair on the joint torques of the player as an example of analysis. The pushing motion during short distance dash was focused in the present study. The simulation model was constructed based on a multibody dynamics analysis software. Pushing motions by a player were acquired in the experiment by using a motion capture system and a specially developed wheelchair ergometer. Simulations reproducing the experimental conditions were conducted using the acquired pushing motions. The simulation model was validated since it could predict the propulsion torque and angular velocity overall within 10% error, although there was a room for improvement especially for the instantaneous characteristics around the timing of initial contact between the hand and hand rim. A parameter study changing the seat height of the wheelchair was conducted using the constructed simulation model. It was found that the joint torques of the thorax and shoulder decreased according to the decrease in the seat height, while joint torque of the elbow increased. It suggests that there is a trade-off relationship between the joint torques of the thorax and shoulder and that of the elbow with respect to the seat height.

Keywords

• wheelchair tennis
• pushing motion
• sports engineering
• sports biomechanics
• multibody dynamics
• simulation