Changes in squat strength and kendo men-strike biomechanics after velocity-based and percentage-based resistance training: an exploratory comparison

Purpose: This exploratory study compared changes in squat strength and kendo men-strike biomechanics between velocity-based training (VBT) and percentage-based training (PBT) conditions.

Methods: Twelve university kendo athletes completed a 7-week back-squat intervention under VBT (n = 7) or PBT (n = 5). Allocation was based on academic year rather than randomisation. Before and after training, squat one-repetition maximum (1RM), men-strike motion time, push-off-phase rate of force development over 0–100 ms (RFD0–100 ms), and the temporal overlap of high-extension-torque phases among the hip, knee, and ankle joints were assessed.

Results: Absolute and relative squat 1RM increased in both conditions. Between-condition differences in change were 14.1 kg for absolute 1RM (95% CI [4.5, 23.8]) and 0.309 kg · kg–1 for relative 1RM (95% CI [0.136, 0.482]), favouring VBT. The between-condition difference for RFD0–100 ms also favoured VBT (27.62 N · kg–1 · s–1; 95% CI [–11.75, 66.98]), but the CI included zero. Differences were small and uncertain for men-strike motion time (–0.025 s; 95% CI [–0.142, 0.092]) and the overlap index (1.6 percentage points; 95% CI [–4.8, 8.1]).

Conclusions: Between-condition differences were clearest for squat strength, whereas evidence for kendo-specific biomechanical changes was limited. Because academic year was confounded with intervention condition, and the interventions differed in load progression and autoregulation, the

Findings: cannot be attributed to velocity feedback alone. Evidence for transfer to faster men-strike performance remains inconclusive.