ABSTRACT
A study was undertaken to investigate the influence of shaft flexibility on the positioning of the club face during the downswing. To accomplish this task, a computerized model of deflections occurring in the shaft over the period of the down-swing was developed. Employing Lagrangian dynamics, equations of motion for bending and for twist coordinates of the shaft are produced. In addition to being dependent on stiffness, these deformations are a function of the forces generated by the acceleration of the shaft during the swing. To determine these forces, video images of a real swing are converted to digital data using a motion analysis software package. The equations of motion can then be solved numerically, yielding the position and orientation of the club face over the course of the swing.
