Effects of 20% and 30% velocity loss threshold-based resistance priming on short-term lower-body jumping performance in athletes

Abstract This study aimed to investigate the short‑term effects of resistance priming sessions at 20% and 30% velocity‑loss thresholds (VLTs) on countermovement‑jump (CMJ) performance. Twenty‑four male athletes completed all three experimental conditions in a randomized crossover design: the 20% VLT condition performed three sets of moderate‑load back squats terminated at a 20% velocity loss, the 30% VLT condition performed three sets terminated at a 30% velocity loss, and the control condition involved passive rest. CMJ performance was evaluated pre‑exercise and at 6 h, 24 h, and 30 h post‑priming. No meaningful between‑condition differences were observed at 6–24 h. Within‑group comparisons revealed improvements in CMJ height at 30 h under both priming conditions (20% VLT: +5.5%, d = 0.59; 30% VLT: +2.8%, d = 0.38), with the 20% VLT condition also showing improvements in theoretical maximal velocity (V₀) and force (F₀). For our primary outcome CMJ height, the condition × time interaction did not reach statistical significance ( P = 0.088). These within‑group findings suggest delayed CMJ improvements following moderate‑load priming, but do not confirm a differential effect between the 20% and 30% VLT conditions.