Data Sheet 1_Foot–ground interaction and clubhead speed: impulse-based energy transfer as the key mechanism in the golf swing.docx

IntroductionClubhead speed is a primary determinant of golf performance, typically linked to the kinetic chain. Although foot–ground interaction variables such as plantar pressure and center-of-pressure behavior associate with performance, the mechanisms linking these factors to clubhead speed remain unclear. This study investigated whether foot–ground interaction influences clubhead speed directly or through intermediate mechanisms, such as segmental sequencing and energy transfer.
MethodsThirty right-handed golfers (15 professionals, 15 high-level amateurs) performed maximal swings using a driver and a 7-iron. Data from both club types were pooled to identify generalized biomechanical mechanisms across equipment. Kinematics, ground reaction forces, and plantar pressure were recorded. Impulse-based energy transfer efficiency—defined as the effectiveness of mechanical impulse transmission from proximal segments to the club head—was computed. Principal component analysis-derived constructs for hierarchical regression and serial mediation models, controlling for skill level.
ResultsFoot–ground interaction variables explained 35.5% of the variance in clubhead speed. Adding trunk sequencing and impulse-based energy transfer efficiency increased the explained variance to 75.4% (adjusted R2=0.715). Mediation analysis revealed that early-phase center-of-pressure behavior did not directly influence clubhead speed. Instead, a significant indirect pathway through impulse-based energy transfer efficiency was found (accounting for 55% of the total variance in the mediation model); trunk sequencing did not independently mediate this relationship, while skill level remained a significant covariate.
ConclusionFoot–ground interaction enhances clubhead speed primarily by facilitating efficient impulse-based energy transfer along the kinetic chain rather than through direct mechanical effects. These findings support integrating foot-pressure and energy-flow analyses for performance assessment and evidence-based training.