Effects of In-Season Velocity-Based Resistance Training on Boxing-Specific Performance in Collegiate Boxers: A Companion Report from a Randomized Controlled Trial

Objective: This article reports the prespecified boxing-specific component of a randomized controlled trial comparing velocity-based resistance training (VBT) with percentage-based training (PBT) in collegiate boxers. Boxing-specific performance was specified as a parallel primary outcome domain in the original ethics-approved protocol, although no single boxing-specific measure was designated as the sole primary endpoint; the five measures are therefore reported as prespecified exploratory outcomes. Methods: The trial was designed before participant recruitment to address two parallel research objectives: changes in general lower-limb performance and changes in boxing-specific performance. Twenty-eight male collegiate boxers were randomly allocated to VBT (n = 14) or PBT (n = 14). Results for lower-limb strength, jumping, and sprinting from the same trial have been reported previously. The present report focuses on lead and rear straight-punch (LSP and RSP) force and continuous-punch (CP) frequency over 10 s, 30 s, and 1 min. Both groups were prescribed the back squat, Bulgarian split-squat, and deadlift twice weekly for eight weeks. PBT participants completed four sets of five repetitions at 70% of one-repetition maximum (1RM), whereas VBT participants were prescribed four sets using the velocity associated with 70% 1RM and ended each set at 10% velocity loss. Results: The between-group differences in mean change, calculated as VBT minus PBT, were 6.97 kg for lead straight-punch force (95% CI: 0.40 to 13.54), 7.21 kg for rear straight-punch force (95% CI: 3.56 to 10.86), 4.47 punches·10 s−1 for 10 s continuous-punch frequency (95% CI: 0.33 to 8.62), 5.05 punches·30 s−1 for 30 s continuous-punch frequency (95% CI: 0.14 to 9.96), and −2.65 punches·min−1 for 1 min continuous-punch frequency (95% CI: −13.97 to 8.67). Conclusions: Greater mean improvements in straight-punch force and short-duration continuous-punch performance were observed in the VBT group, although the precision of several estimates was limited and the findings should be interpreted cautiously because multiple exploratory outcomes were analyzed without formal multiplicity adjustment. For the 1 min test, there was no statistically conclusive evidence of a between-group difference. Registration: The trial was retrospectively registered with the Chinese Clinical Trial Registry (ChiCTR2500111377), and the study materials were subsequently registered on the Open Science Framework (OSF; DOI: 10.17605/OSF.IO/VY6TS).