Acute effect of inspiratory resistive loading on sprint interval exercise performance in team-sport athletes.

This study examined acute effects of inspiratory resistive loading (IRL) during rest intervals on sprint interval exercise (SIE) performance. In a randomized crossover design, nine collegiate basketball players performed IRL (15 cmH2O) or passive recovery (CON) at 5-min rest intervals during and immediately after 6 sets of a 30-s SIE test. Performance, muscular oxygenation of vastus lateralis, blood lactate and pH were measured at each condition. Blood lactate at 5-min (-20.5 %) and 20-min (-21.3 %) after SIE were significantly lower in IRL than in CON. The pH at 5-min after SIE was significantly higher in IRL than in CON (+0.8 %, p <  0.05). However, the total work in IRL was significantly lower than in CON (-2.7 %, p <  0.05). Average changes in total hemoglobin at rest intervals in IRL were significantly lower than in CON (-34.5 %, p <  0.05). The IRL could attenuate exercise-induced metabolic acidosis; however, the decreased blood flow at rest intervals might increase the physical challenge in SIE.