Effects of Physical Training on Cardiorespiratory Fitness in Children

Abstract Changes in submaximal and maximal HR and vdot02 as a result of 8 wk of interval training were studied in boys aged 10–12; 13 boys trained while 11 acted as controls. Training HR's averaged approximately 90% of the mean maximal HR. vdotO2 max did not change significantly with training. The apparently high threshold for a training effect on the vdotO2 max in children is probably related to their naturally active lives: the stresses induced by short-term training are probably small as compared to the overall activities of children. On the other hand, submaximal heart rate during bicycle and treadmill exercise decreased significantly with training. The O2 cost of these submaximal tasks remained unchanged. The findings suggest that the use of vdotO2 max as the only training criterion for cardiorespiratory fitness may be misleading. Since most work tasks proceed at a submaximal rate, and a training-induced improvement in submaximal response was demonstrated without improvements at maximal effort, perhaps submaximal physiological and performance measures are more important than maximal ones in the assessment of cardiorespiratory fitness.