Prior heavy-intensity exercise's enhancement of oxygen-uptake kinetics and short-term high-intensity exercise performance independent of aerobic-training status.

Abstract

Prior high-intensity exercise can improve exercise performance during severe-intensity exercise. These positive alterations have been attributed, at least in part, to enhancement of overall oxygen-uptake (VO2) kinetics. To determine the effects of prior heavy-intensity exercise on VO2 kinetics and short-term high-intensity exercise performance in individuals with different aerobic-training statuses. Fifteen active subjects (UT; VO2max = 43.8 ± 6.3 mL · kg-1 · min-1) and 10 well-trained endurance cyclists (T; VO2max = 66.7 ± 6.7 mL · kg-1 · min-1) performed the following protocols: an incremental test to determine lactate threshold and VO2max, 4 maximal constant-load tests to estimate critical power, and two 3-min bouts of cycle exercise, involving 2 min of constant-work-rate exercise at severe intensity followed by a 1-min all-out sprint test. This trial was performed without prior intervention and 10 min after prior heavy-intensity exercise (ie, 6 min at 90% critical power). The mean response time of VO2 was shortened after prior exercise for both UT (30.7 ± 9.2 vs 24.1 ± 7.2 s) and T (31.8 ± 5.2 vs 25.4 ± 4.3 s), but no group-by-condition interaction was detected. The end-sprint performance (ie, mean power output) was improved in both groups (UT ~4.7%, T ~2.0%; P < .05) by prior exercise. The effect of prior heavy-intensity exercise on overall VO2 kinetics and short-term high-intensity exercise performance is independent of aerobic-training status.