Five-year longitudinal predictors of clubhead speed in elite junior golfers: Predominant contribution of lean body mass and dietary patterns

Objectives This study aimed to identify longitudinal predictors of clubhead speed (CHS) in elite junior golfers and investigate the associations between physical development and habitual dietary patterns across 5 years. Design Five-year longitudinal study. Method Elite junior golfers (n = 323; aged 11–17 years; approximately 50% male) were assessed for CHS, lean body mass (LBM) and dietary intake via a validated questionnaire. The final analysis used n = 244 observations obtained through a standardised CHS measurement protocol. Principal component analysis was used to identify key dietary patterns. Linear mixed models were employed to identify CHS predictors, incorporating age, LBM, sex and dietary factors as fixed effects. Results LBM emerged as the strongest modifiable predictor of CHS (β = 0.43, p < 0.001), with a standardised coefficient threefold greater than chronological age (β = 0.14, p < 0.001). Each 1-kg increment in LBM predicted a 0.21 m/s increase in CHS (B = 0.21). Total energy intake positively predicted CHS (β = 0.09, p = 0.029), whereas a dietary pattern marked by comparatively lower protein and fat intake was negatively associated with improvements (β = −0.07, p = 0.041). Overall, the cohort exhibited a mean energy deficit of 8%. Conclusions CHS development in elite junior golfers is predicted by functional muscle mass gains rather than passive maturation. For coaches, long-term athletic development programmes may benefit from integrating strength-focused training alongside strategies ensuring adequate energy, protein and fat intake.