F . H . ( Sam ) Froes andS . J . Haake Materials and Science in Sports The Effect of Golf Club Shaft Stiffness on Golf Performance Variables — Implications for Club - Fitting

The process of matching clubs with appropriate shafts to individual players is largely one of trial and error. Bending stiffness or shaft flex, mass, damping, torsional stiffness, and bend point are widely accepted as being the five main shaft properties that affect performance in golf. Considerable debate surrounds the individual and combined dynamic influence of these factors during the golf swing. The aim of this paper was to examine the effects of 5-iron clubs with shafts of different bending stiffness on selected golf performance measures. A laboratory-based experimental approach was used in the study. Eighty-four right-handed male amateur golfers gave their informed consent and participated in this investigation. Anthropometric and physical fitness measures were obtained for each subject and used in correlational analyses with shot performance measures. Objective measurements of the stance/ set-up and swing kinematics along with clubhead presentation variables were obtained for each of the golfers during swings for each of three experimental clubs. A visual inspection of body kinematics data revealed differences in shaft stiffness had no observable effect within a given subject, although obvious and expected differences were noted between subjects. While statistically significant differences were noted among shaft types for clubhead speed, solid hit factor and ball/ clubhead impact location, the actual magnitudes of these differences were considered negligible. No significant differences were noted for any of the postural variables at address due to shaft stiffness. These scientific findings lend support to conventional wisdom that shaft bending stiffness is perhaps most relevant to feeP of the golf club. However, the present study did not take into account other important launch conditions of the ball such as launch angle and spin rate. Materials and Science in Sports Edited by F.H. (Sam) Froes IMS (The Minerals, Metals & Materials Society), 2001