Purpose: This study examined the effects of age on recovery of peak torque of knee extensors (PTEX) and flexors (PTFL), and total work (TW) during high-intensity intermittent 30-s (HI30) and 60-s (HI60) exercise in boys (N = 19; age, 11.4 ± 0.5 yr), teens (N = 17; age, 14.7 ± 0.4 yr), and men (N = 18; age, 24.1 ± 2.0 yr).
Methods: Each age group's subjects were subdivided to participate in an HI30 or an HI60 protocol. The HI30 involved 4 × 18 maximal knee extensions and flexions (1-min rest between sets), and the HI60 comprised of 2 × 34 reps (2-min rest). PTEX (N·m·kg-1), PTFL (N·m·kg-1), and TW (J·kg-1) were recorded at each set. The percent recovery of PTEX, PTFL, and TW was calculated as percent of the value achieved in the first set.
Results: In HI60, the percent recovery for PTEX, PTFL, and TW after the first set was higher in boys compared with teens and men (P < 0.01). In HI30, the percent recovery for PTEX, PTFL, and TW was higher in boys compared with men in all sets (P < 0.01), and in teens compared with men in the last two sets (P < 0.05). The percent recovery of PTFL and TW was higher in boys compared with teens in the last two sets (P < 0.05). Lactate increase was most pronounced in men, less pronounced in teens, and least pronounced in boys (P < 0.01). Heart rate recovered faster in boys compared with teens and men in both protocols (P < 0.05).
Conclusions: The recovery was faster in boys than in teens and men during HI30 and HI60, as evident by the greater percent recovery in boys for a given time. Furthermore, it appears that the rate of recovery during HI30 and HI60 anaerobic exercise is maturity dependent.