Abstract
The purpose of this study was to formulate a methodology to evaluate dynamical functional roles of upper joint torques during golf swing motion in considering deformation of club shaft. The upper limb segments and grip handle part of golf club were modeled as a system of seven-rigid linked segments, and constraint axes of the elbow and wrist joints were modeled with constraint equation in order to consider the anatomical degree of freedom of the joint. The deformation of club shaft was modeled as angular displacements of virtual joint settled between adjacent segments by dividing club shaft into rigid segments. The angular displacements were defined as roll-pitch-yaw angles, and joint torques at each virtual joint were calculated by assuming rotational spring and damper about each axis of the virtual joints. A recurrent equation with respect to the expanded generalized velocity vector, which consists of generalized velocity vector and the time integration of the velocity vector, is derived to calculate the contribution of the joint torque terms, external joint force term, and gravity term to the generation of the expanded generalized velocity vector.
