The Role of Lower Limb Kinetics in Boxing Punches and the Impact of Fatigue on Biomechanical Performance

<b>Purpose:</b> This study investigated the contribution of lower limb kinetics to punch performance in amateur boxing and examined the effects of fatigue on biomechanical efficiency. <b>Methods:</b> Ten male amateur boxers performed six punch types (jab, cross, left hook, right hook, left uppercut, right uppercut) under non-fatigued and post-fatigue conditions. Ground reaction force (GRF) and rate of force development (RFD) were measured using dual force plates, while punch outputs were assessed via a boxing force sensor. Fatigue was induced using a 9.5 min lower-body circuit. <b>Results:</b> Pre-fatigue, the cross punch generated the highest outputs for punch force (1475.42 N), GRF (947.54 N), and RFD (3973.38 N/s). Post-fatigue, punch force declined significantly across all punches (-4.26%, <i>p</i> = 0.027), with the greatest reductions in the cross and left hook. RFD responses were variable, with compensatory increases observed in some punches. Intra-individual analysis revealed greater fatigue-induced declines in the weakest punches (-9.84%, <i>p</i> = 0.001) compared with the strongest (-4.63%, <i>p</i> = 0.027). <b>Conclusions:</b> Lower limb force generation, particularly rear-leg drive, is critical to punch effectiveness and fatigue resilience. Conditioning programs should prioritise lower limb endurance while addressing performance variability across punch types.