The effect of high-intensity interval training on stroke volume and endurance performance in trained endurance athletes

This study compared the effects of two training protocols, high intensity (HIT) and low intensity training (LIT) on cardiovascular and performance adaptations. Twelve male cyclists (V02 max 61.7±3.6 mL·ki1 ·min-1) completed an HIT or LIT, volume-matched periodized training plan. Maximum stroke volume increased for all subjects following long duration training and decreased with HIT and LIT (p=0.002). V0 max and 2 maximum cardiac output did not change. Lactate minimum power output increased 5% following duration training, and then a further 9% (275 to 297W) with HIT but not LIT. Peak aerobic power output increased from 425W to 460W with HIT, 405W to 425W for the LIT group with taper. Time trial performance increased linearly for both groups (p < 0.001). The data demonstrates that HIT does not change maximal cardiac output when following long duration training, and time trial per