Recovery of muscle power after high-intensity short-term exercise: comparing boys and men.

This study was conducted to determine whether boys differ from men in their ability to recover from high-intensity exercise. Two groups of volunteers, 8 prepubertal boys (9-12 yr) and 8 young men (19-23 yr), were similar in their peak oxygen uptake (49.6 +/- 6.6 vs. 51.1 +/- 6.6 ml.min-1 x kg-1), adiposity, and activity levels. On three different occasions subjects performed two consecutive 30-s all-out cycling tasks [Wingate anaerobic test (WAnT)], separated by a 1-, 2-, or 10-min recovery interval. In the boys, mean power reached 89.9 +/- 3.6% of the initial value after 1 min of recovery, 96.4 +/- 2.3% after 2 min, and 103.5 +/- 1.3% after 10 min. For the men, the values were 71.2 +/- 2.6, 77.1 +/- 2.4, and 94.0 +/- 1.3%, respectively (boys vs. men, P < 0.0001). Relative to the external work performed during the first WAnT, the boys had a higher net oxygen uptake (exercise--resting) during the test than the men (83.8 +/- 18.4 vs. 57.8 +/- 6.1 ml/kJ). After the WAnT, the net CO2 output and the respiratory exchange ratio were lower in the boys, and they recovered faster. It was concluded that boys recover faster than men from high-intensity short-term exercise. This may reflect a lower reliance on glycolysis during the WAnT in the boys, leading to less acidosis. It is also possible that the boys had a faster postexercise removal of metabolites.