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 (VO 2 max), followed by five submaximal constant-load cycling trials to derive individual power–VO 2 regression equations. The three priming interventions included HIPE, LIPE, and LIPE-BFR. Key physiological parameters, including pulmonary oxygen uptake kinetics, muscle oxygen saturation (SmO 2 ), accumulated blood lactate (ABLa) concentration, accumulated oxygen uptake (AVO 2 ), 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 SmO 2 (SmO 2 min) and steady-state SmO 2 (SmO 2 ss) during exercise ( P < 0.05). HIPE elicited greater metabolic responses, including higher AVO 2 , AOD, and ABLa. Significant correlations were observed between VO 2 kinetics and metabolic demand, as well as between SmO 2 -derived indices and ABLa ( P < 0.05). However, no significant differences were found among the three conditions in VO 2 kinetics or metabolic outcomes during the subsequent severe-intensity cycling bout ( P > 0.05), except for a higher VO 2 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.