Effects of priming exercise on oxygen uptake kinetics, muscle oxygenation, and metabolic load in trained anaerobic athletes: a randomized crossover trial

Background This study aimed to compare the acute and residual physiological responses elicited by three different priming exercise strategies, including high-intensity priming exercise (HIPE), low-intensity priming exercise (LIPE), and low-intensity priming exercise with blood flow restriction (LIPE-BFR), on oxygen uptake kinetics, muscle oxygenation, and metabolic load during severe-intensity cycling in trained anaerobic athletes. Methods Sixteen trained anaerobic athletes completed a randomized crossover protocol with three priming conditions (HIPE, LIPE, and LIPE-BFR) in a randomized order. The experimental protocol began with an incremental exercise test to determine maximal oxygen uptake (VO2max), followed by five submaximal constant-load cycling trials to derive individual power–VO2 regression equations. The three priming interventions included HIPE, LIPE, and LIPE-BFR. Key physiological parameters, including pulmonary oxygen uptake kinetics, muscle oxygen saturation (SmO2), accumulated blood lactate (ABLa) concentration, accumulated oxygen uptake (AVO2), and accumulated oxygen deficit (AOD), were assessed to quantify oxygen utilization and metabolic demand across sessions. Results Compared with HIPE, both LIPE and LIPE-BFR induced significantly lower amplitude (A) and longer time delay (TD), along with reduced reduced minimum SmO2 (SmO2min) and steady-state SmO2 (SmO2ss) during exercise (P < 0.05). HIPE elicited greater metabolic responses, including higher AVO2, AOD, and ABLa. Significant correlations were observed between VO2kinetics and metabolic demand, as well as between SmO2-derived indices and ABLa (P < 0.05). However, no significant differences were found among the three conditions in VO2 kinetics or metabolic outcomes during the subsequent severe-intensity cycling bout (P > 0.05), except for a higher VO2 baseline in the HIPE group (P < 0.05). Conclusion Although the three priming strategies elicited distinct acute physiological responses, their residual effects on oxygen uptake kinetics and metabolic outcomes during subsequent severe-intensity exercise were largely comparable. Future studies should further explore alternative priming protocols and refine experimental designs to better clarify the effects of priming.