The role of pelvis-thorax coupling in controlling within-golf club swing speed

Abstract

Pelvis-thorax coordination has been recognised to be associated with swing speed. Increasing angular separation between the pelvis and thorax has been thought to initiate the stretch shortening cycle and lead to a more forceful downswing. The purpose of this study was to determine whether pelvis-thorax coupling played a significant role in scaling single-club swing speed in a group of low-handicap golfers (mean handicap = 4.1). Sixteen participants played shots to target distances determined based on their typical 5- and 6-iron shot distances. Half the inter-club distance was used to create three swing effort conditions: `minus', `norm', and `plus'. Ten shots were played under each swing effort condition using both the 5-iron and 6-iron, resulting in six shot categories and 60 shots per participant. No significant differences were found for X-factor for either club or swing effort. X-factor stretch showed significant differences for both club and swing effort. Continuous relative phase (CRP) results mainly showed evidence of the stretch shortening cycle in the downswing and that it was more pronounced late in the downswing as swing effort increased. Inter-individual variability in CRP curves was substantial, demonstrating the need for individual analyses when investigating complex coordination patterns such as the golf swing.