The effect of fatiguing lower-body exercise on punch forces in highly-trained boxers

This study aimed to examine the effect of intense intermittent lower-body and trunk exercise (rowing) on punching performance in 28 highly-trained male amateur boxers. Straight- and bent-arm punch performances were assessed with a custom-built punch integrator using a 3-min maximal-effort punch test, completed in both non-fatigued (ROW_pre) and fatigued (ROW_post) states. A within-subject repeated measures design was implemented; subjects completed ROW_pre, then 9 × 1-min bouts of rowing (1-min rest intervals), followed by ROW_post. Peak punch force and force-time variables, including impulse and rate of force development (RFD; calculated to five time points), were assessed. Differences between ROW_pre and ROW_post for each punch type (jab, cross, lead- and rear-hand hook) were tested with a linear mixed model, and effect sizes (Cohen's d) were calculated. Results showed significant (p < 0.05) reductions in punch force in ROW_post compared to ROW_pre for all punch types as well as significant delays in the time to reach specific force levels, and relative percentages of peak force (RFD) in all punches except the jab. It is likely that fatigue of the lower body and trunk muscles impaired ground reaction force, and thus punch force, production. This effect was larger in punches that involved a greater degree of trunk rotation, crosses and hooks, than in the jab which relies predominantly on arm extension. These findings reveal the negative effect of fatigue on punch force production, and provide evidence that lower-body and trunk force are important for generating punch force. HighlightsThe ability of the lower body to generate force affects the magnitude of punch force produced in trained boxers.A bout of intense rowing exercise significantly reduces punch force, and rate of force development. This should be carefully considered when programming and scheduling boxing specific training sessions and strength and conditioning sessions.While non-specific fatigue affected the punch performance of boxers, the authors call for further research to examine the effects of fatigue sustained during a boxing bout in comparison to non-boxing muscular fatigue and a non-exercise control.