Reducing the volume of sprint interval training does not diminish maximal and submaximal performance gains in healthy men

The present study examined the effect of reducing sprint interval training (SIT) work-interval duration on increases in maximal and submaximal performance. Subjects (n = 36) were assigned to one of three training groups: endurance training (ET; 60 min per session for weeks 1-2, increasing to 75 min per session for weeks 3-4), or sprint interval training consisting of either repeated 30 (SIT 30) or 15 (SIT 15) second all-out intervals (starting with 4 bouts per session for weeks 1-2, increasing to 6 intervals per session for weeks 3-4). Training consisted of cycling 3 times per week for 4 weeks. While there was a significant main effect of training on such that was elevated post-training, no significant difference was observed in the improvements observed between groups (ET similar to 13 %, SIT 30-4 %, SIT 15-8 %). A significant main effect of training was observed such that lactate threshold and critical power were higher during post-testing across all groups (p < 0.05). There was a main effect of training (p < 0.05) on Wingate peak power with no differences observed between groups at post-training. Together, these results indicate that reducing SIT work-interval duration from 30 to 15 s had no impact on training-induced increases in aerobic or anaerobic power, or on increases in lactate threshold (absolute) and critical power.