Upper Limb Joint Torque Distribution Resulting from the Flat Tennis Serve Impact Force

The serve is a vital part of a tennis player’s game. Serve has to be fast and powerful to enhance the chance of winning the initial point. The extreme intensity and severity of the ball racket collision involved at the service often lead to various upper limb injuries. Detailed biomechanical models of the human upper arm are needed to study how the impulse force propagates to individual joint or muscle level. This study investigates the torque distribution resulting from the impact force of the flat service stroke based on a detailed 9- Degrees of Freedom (DoF) kinematic model. Five trials were sampled from a professional level tennis player during the flat service scenario. A Qualisis motion capturing system with six cameras was used to capture 3 Dimensional (3D) position data of the subject, at a sampling rate of 240 Hz. The torque distribution was quantitatively analyzed using a Jacobian matrix. The results of the analysis reflected that the highest torque was apportioned to sterno-clavicular joint followed by elbow, sterno-clavicular joint and wrist joint respectively. A statistical based sensitivity analysis has been carried out on upper limb joints. The proximal radioulnar Joint was found to be the most sensitive joint with respect to torque distribution.