A subject-specific, torque-driven, 3D computer simulation model with eight segments was developed to investigate the effects of different variables belonging to the racket and player on the wrist and elbow loadings in one-handed tennis backhand groundstrokes. Wobbling masses were included to represent soft tissue movement. The string-bed was represented by nine-point masses connected to each other and the racket frame with elastic springs. There were twelve rotational degrees of freedom: three at the shoulder, two at the elbow, two at the wrist, three at the grip and two between the racket handle and racket head. Seven pairs of torque generators were used to control (via activation profiles) the joint angle changes in the model. An elite player was chosen to perform consistent and high standard backhand topspin strokes and a Vicon System was used to record the performances.