Long start strategy in high-intensity interval training in Rugby Union Academy players

Introduction High-intensity interval training (HIIT) protocols with varied parameters have been investigated to optimise the time spent at high levels of oxygen uptake. However, to date, the physiological and perceptual responses to a long-start approach (i.e., longer initial work phases followed by shorter subsequent phases) have not been investigated. The aim of the study was to compare external load, physiological responses, and rating of perceived exertion (RPE) between a constant work-interval HIIT protocol (HIIT-C) and a long-start strategy (HIIT-LS) in rugby union players. Methods Nine male academy rugby union players (19.9 ± 0.8 years) from a professional team randomly completed both HIIT-C and HIIT-LS in a counterbalanced design. HIIT-C consisted of 2 × 8 repetitions of 30 s work with 15 s passive recovery and 3 min rest between sets. HIIT-LS consisted of 2 × 7 repetitions (3 × 45 s followed by 4 × 30 s), each separated by 15 s passive recovery, with 3 min rest between sets. Exercise intensity was set at 88% and 83% of maximal velocity achieved during the 30-15 Intermittent Fitness Test for HIIT-C and HIIT-LS, respectively. Differences between protocols were assessed using a paired t -test or, when appropriate, a Wilcoxon signed-rank test depending on data distribution. Results HIIT-LS elicited a greater total distance and distance covered above 7 km h −1 compared to HIIT-C ( p < 0.01), despite a lower mechanical work distance ( p < 0.05). No differences were observed in time spent ≥90%V˙O 2 peak ( p = 0.25). Perceived exertion was significantly lower following HIIT-LS ( p < 0.05). Discussion Time spent at high levels of oxygen uptake did not differ between HIIT-LS and HIIT-C. However, HIIT-LS was better tolerated, as reflected by lower perceived exertion, suggesting potential practical benefits for training load management. Future research should investigate the effects of incorporating HIIT-LS into long-term training interventions aimed at improving endurance performance in team-sport athletes.