Endurance Performance during Severe-Intensity Intermittent Cycling: Effect of Exercise Duration and Recovery Type.

Slow component of oxygen uptake (VO2 SC) kinetics and maximal oxygen uptake (VO2 max) attainment seem to influence endurance performance during constant-work rate exercise (CWR) performed within the severe intensity domain. In this study, it was hypothesized that delaying the attainment of VO2 max by reducing the rates at which VO2 increases with time (VO2 SC kinetics) would improve the endurance performance during severe-intensity intermittent exercise performed with different work:recovery duration and recovery type in active individuals. After the estimation of the parameters of the VO2 SC kinetics during CWR exercise, 18 males were divided into two groups (Passive and Active recovery) and performed at different days, two intermittent exercises to exhaustion (at 95% IVO2 max, with work: recovery ratio of 2:1) with the duration of the repetitions calculated from the onset of the exercise to the beginning of the VO2 SC (Short) or to the half duration of the VO2 SC (Long). The active recovery was performed at 50% IVO2 max. The endurance performance during intermittent exercises for the Passive (Short = 1523 ± 411; Long = 984 ± 260 s) and Active (Short = 902 ± 239; Long = 886 ± 254 s) groups was improved compared with CWR condition (Passive = 540 ± 116; Active = 489 ± 84 s). For Passive group, the endurance performance was significantly higher for Short than Long condition. However, no significant difference between Short and Long conditions was found for Active group. Additionally, the endurance performance during Short condition was higher for Passive than Active group. The VO2 SC kinetics was significantly increased for CWR (Passive = 0.16 ± 0.04; Active = 0.16 ± 0.04 L.min-2 ) compared with Short (Passive = 0.01 ± 0.01; Active = 0.03 ± 0.04 L.min-2 ) and Long (Passive = 0.02 ± 0.01; Active = 0.01 ± 0.01 L.min-2 ) intermittent exercise conditions. No significant difference was found among the intermittent exercises. It can be concluded that the endurance performance is negatively influenced by active recovery only during shorter high-intensity intermittent exercise. Moreover, the improvement in endurance performance seems not be explained by differences in the VO2 SC kinetics, since its values were similar among all intermittent exercise conditions.