Acute effects of bench press conditioning performed with different velocity-loss thresholds on punch performance in elite adolescent boxers

Velocity-loss (VL) thresholds may help regulate the balance between potentiation and fatigue during post-activation performance enhancement protocols; however, their effects on boxing-specific performance remain unclear. This study investigated the acute effects of bench press conditioning regulated by different VL thresholds on straight-punch performance in adolescent boxers.

Eighteen male boxers (17.6 ± 0.7 years) completed four conditions in a randomized, counterbalanced crossover design: an active control condition (CON; two sets of 10 bench press repetitions using a habitual warm-up load below 30% one-repetition maximum [1RM]) and three VL conditions consisting of two sets of bench press at 85% 1RM terminated at 10% (VL10%), 20% (VL20%), or 30% (VL30%) velocity loss. Lead- and rear-hand peak punch velocity (PPV), peak punch force (PPF), and an estimated peak punch-power index (PPP) were assessed at baseline and 4, 8, 12, and 16 min after conditioning. Outcomes were analyzed using linear mixed-effects models, followed by Dunnett-adjusted comparisons of each VL condition with CON. Additional Tukey-adjusted pairwise comparisons were performed among VL10%, VL20%, and VL30%.

Significant condition × time interactions were observed for rear-hand PPV, lead- and rear-hand PPF, and lead- and rear-hand PPP (all p ≤ 0.046), but not for lead-hand PPV (p = 0.391). At 8 and 12 min, VL10% and VL20% produced higher rear-hand PPV, PPF, and PPP and higher lead-hand PPP than CON (p ≤ 0.039; Hedges' g = 0.835-1.267). In contrast, VL30% produced lower rear-hand PPV, lead- and rear-hand PPF, and rear-hand PPP than CON at 4 min and remained lower for selected outcomes at 8-12 min (p ≤ 0.046; g = -2.439 to -0.814). Direct VL comparisons showed no significant differences between VL10% and VL20%, whereas both conditions produced higher values than VL30% for several outcomes at selected time points (p ≤ 0.045). Most between-condition differences were no longer evident at 16 min.

Under the present protocol in the 18 male adolescent boxers studied, VL10% and VL20% were associated with favorable differences in several punch-performance outcomes after 8-12 min of recovery, whereas VL30% was associated with lower performance during the earlier recovery period. Direct comparisons showed no significant differences between VL10% and VL20%, whereas both conditions produced higher values than VL30% for several outcomes at selected time points. However, because repetition volume was not matched, these findings do not isolate the effect of VL threshold or establish an optimal threshold.