Abstract
The purpose of this study was to formulate the dynamic contribution of estimated muscle force in consideration of muscle contraction mode. The upper body with a racket was modeled as a linked eleven-segment system. The analytical form of the equation for the system was obtained from the combination of 1) equations of motion for individual segments, 2) equations for constraint condition in which adjacent segments are connected by individual joint, and 3) geometric equations for anatomical constraint axes of wrist and elbow joints. Motion dependent term, which shows large contribution in generation of racket head speed, is converted into other terms by using a recurrent equation with respect to the generalized velocity vector in discrete time system. Individual muscle torques, which are generated by the muscle forces, are estimated by using a musculoskeletal modeling software (SIMM; MusculoGraphics Inc.). With the estimated muscle torques, the formula for muscle torque contribution to the generation of generalized velocity vector of the system in consideration of muscle contraction mode is derived.
