Ischemic preconditioning enhances 6-hour sprint, jump, and isometric strength responses to complex training in resistance-trained males: a randomized controlled pilot trial

Objective Optimization of the recovery-adaptation timeline following high-intensity training is critical for athletic performance. However, the specific time-course effects of ischemic preconditioning (IPC) when combined with complex training (CT) remain unclear. This study aimed to examine the delayed potentiation effects of IPC applied prior to a CT protocol on power and speed performance over a 48-hour period in resistance-trained males. Methods Sixteen resistance-trained males (relative back squat one-repetition maximum (1RM) ≥ 1.5×body mass) with at least one year of resistance training experience participated in this randomized controlled trial. Participants were assigned to either an IPC with CT group (IPC+CT; n = 8) or a CT-only control group (CT-only; n = 8). The IPC protocol involved five 5-minute cycles of bilateral thigh occlusion (220 mmHg) alternating with 5-minute reperfusion periods, before receiving a lower-body CT intervention. Sprint performance (10-m and 30-m sprint), change-of-direction ability (5-0-5 test), jump performance (standing long jump (SLJ), countermovement jump [CMJ], squat jump (SJ), drop jump (DJ), and continuous vertical jump (CVJ)), maximal strength (1RM back squat), and isometric strength (isometric mid-thigh pull (IMTP)) were assessed at baseline and at 6, 24, and 48 hours post-intervention. This trial was registered at the Chinese Clinical Trial Registry (ChiCTR2500114472). Results At 6 h post-intervention, the IPC+CT group showed more favorable responses than the CT-only group in the 10-m sprint, SLJ, CMJ, SJ, DJ, CVJ, and IMTP outcomes (all P < 0.045). Bonferroni-adjusted within-group comparisons indicated that the 6 h response was partially attenuated at 24 h and 48 h, although the pattern differed between groups and outcomes. These outcome-specific findings should be interpreted as exploratory because no multiplicity adjustment was applied across the different performance outcomes. Conclusions These preliminary findings suggest that IPC applied before CT may promote a short-term improvement in selected power, speed, and isometric strength outcomes, particularly at 6 h post-intervention. Larger sham-controlled studies with physiological measurements are needed to confirm these effects and clarify the underlying mechanisms.