Concurrent Training in Rugby Sevens: Effects of High-Intensity Interval Exercises

Purpose: To assess the impact of 2 high-intensity interval-training (HIT) programs (short interval vs sprint interval training) on muscle strength and aerobic performances in a concurrent training program in amateur rugby sevens players. Methods: Thirty-six amateur rugby sevens players were randomly assigned to strength and short interval training (NT), strength and sprint interval training (SIT), or a strength-only training group (CON) during an 8-wk period. Maximal strength and power tests, aerobic measurements (peak oxygen uptake [VO(2)peak] and maximal aerobic velocity), and a specific repeated-sprint ability (RSA) test were conducted before and immediately after the overall training period. Results: From magnitude-based inference and effect size (ES +/- 90% confidence limit) analyses, the current study revealed substantial gains in maximal strength and jump-height performance in all groups. The difference in change of slow concentric torque production was greater in CON than in SIT (0.65 +/- 0.72, moderate). VO(2)peak and, consequently, mean performance in the RSA test were improved in the SIT group only (0.64 +/- 0.29, moderate; -0.54 +/- 0.35, moderate). Conclusions: The study did not emphasize interference on strength development after INT but showed a slight impairment of slow concentric torque production gains after SIT. Compared with NT, SIT would appear to be more effective to develop VO(2)peak and RSA but could induce lower muscle-strength gains, especially at low velocity.