INFLUENCE OF AEROBIC AND ANAEROBIC FITNESS ON VENTILATORY ANAEROBIC THRESHOLD IN CHILDREN 873

Abstract

Children typically demonstrate a higher ventilatory anaerobic threshold(VAT), expressed as%VO2max, than adults. This might be explained by either a) greater aerobic fitness or b) inferior anaerobic fitness in immature compared to mature subjects. To explore this question, VAT was related to markers of both aerobic and anaerobic fitness in 21 healthy children (11 boys and 10 girls) mean age 9.2 (.5SD) years. Subjects underwent progressive treadmill walking testing to exhaustion with a modified Balke protocol. VAT, determined as the initial upward deflection of VE/VO2, was identifiable in 17. The relationship of VAT as%VO2max to aerobic fitness (VO2max/kg, mile walk time) and anaerobic fitness (vertical jump per kg, 50-yard sprint time) were examined. Mean value of VO2max was 47.6 (6.8) ml/kg/min, VAT 32.8 (3.1) ml/kg/min, and VAT as%VO2max 67.9 (8.3%). Average vertical jump was.68 (.19) cm/kg, mile walk time 14.68 (2.00) min, and 50-yard sprint 9.41 (.64) sec. VAT(%VO2max) was inversely related to both VO2max/kg and vertical jump/kg (r=-.77 and r=-.63 respectively) and directly associated with mile walk and sprint times (r=.44 and.63 respectively). P values were <.05 for all correlations except mile walk time (p=.06). VO2max/kg was closely linked to vertical jump/kg (r=.79, p <.05). These findings indicate that VAT as%VO2max is an inverse indicator of both aerobic and anaerobic fitness in children. This suggests that the greater values for VAT in children compared to adults may best be explained by lower levels of relative anaerobic capacity in immature individuals rather than superior aerobic power.