Purpose: We compared the effects of a high-intensity interval training (HIT) program completed on three consecutive or nonconsecutive days per week for 3 wk on VO2peak, peak aerobic power output (PPOa), and 5-km time trial (TT5k) performance in trained cyclists.
Methods: Fifteen trained cyclists completed a TT5k and an incremental test to exhaustion for VO2peak and PPOa determination before and after training. Pretraining TT5k times were used to form groups, one of which (N=9) performed three HIT sessions per week on consecutive days (CD), while the other (N=6) did so on nonconsecutive days (NCD). Each interval session consisted of up to eight 2.5-min intervals at 100% of PPOa, separated by 4 min of active recovery. Pre- and posttraining TT5k performance, VO2peak, and PPOa were compared using 2x2 (groupxtime) ANOVA with repeated measures on time.
Results: HIT significantly improved VO2peak, PPOa, and TT5k performance in both groups across time (P<0.05); there were no differences between groups. In both groups combined, VO2peak and PPOa increased by 0.2+/-0.2 L.min(-1) (5.7%) and 23+/-15 W (7.2%), respectively, and TT5k velocity and power output increased by 0.9+/-0.8 km.h(-1) (2.6%) and 17+/-19 W (6.9%), respectively. Despite comparable group changes, the individual response varied widely.
Conclusion: CD and NCD similarly improved TT5k performance, VO2peak, and PPOa, but the individual response varied widely in each group. Thus, athletes should experiment with both designs to discern which one optimizes their training.