Umeå University's logo

Children recover faster than adults in repeated sprints, but it is unclear if their aerobic responses differ. Purpose: This study tested the hypothesis that aerobic response (VO2) during repeated sprints is greater in preadolescent boys than in men. Further, this study compared normalization with conventional ratio-scaling and scaling with the use of body mass (BM) as a covariate. Methods: Nine boys (age: 11.8 ± 0.6 years, swimmers) and 11 men (age: 21.7 ± 0.6 years, recreational athletes) performed 10 maximal 6-s cycling sprints separated by 24-s of passive recovery, against two loads (optimum and 50% of optimum). Oxygen uptake (VO2) was measured continuously. Results: Men’s mean power output (MPO) was greater than boys in each sprint, both in absolute (unscaled) values (p < 0.05) and when adjusted for lean leg volume (p < 0.05). Children had lower absolute VO2 (p < 0.05) than men, but when it was adjusted for BM or power-output, VO2 was comparable between men and boys. Thus, most of the difference in VO2 between men and boys was due to body size and power-output differences. Conclusion: Our results suggest that men and boys have similar VO2 during repeated sprints when appropriately adjusted to body mass or power output. Results highlight the importance of using appropriate scaling methods to compare adults’ and children’s aerobic responses to high-intensity exercise.