Nonconsecutive- Versus Consecutive-Day High-Intensity Interval Training in Cyclists

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 V˙O2peak, 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 V˙O2peak 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, V˙O2peak, and PPOa were compared using 2 × 2 (group × time) ANOVA with repeated measures on time.
Results:
HIT significantly improved V˙O2peak, PPOa, and TT5k performance in both groups across time (P < 0.05); there were no differences between groups. In both groups combined, V˙O2peak 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, V˙O2peak, 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.