Predicting aerobic power in children. A comparison of two methods

Objective. To compare the accuracy of two equations for predicting V̇O₂max of children using submaximal cycle ergometry. Experimental design. Repeated measures comparing treadmill measured maximal aerobic power (V̇O₂max) with two methods of predicting V̇O₂max using cycle ergometry testing. Participants. Thirty-three children (15 boys and 18 girls) aged 7- 13 years served as subjects. Measures. Each child completed a treadmill graded exercise test (GXT) to volitional fatigue to assess V̇O₂max. Each child also completed a progressive 9-min, three-stage, submaximal cycle ergometer test. Heart rates obtained during the last minute of each stage of the ergometer test were used to predict V̇O₂max. Predictions were based on a gender-specific modification of the PWC(170) (PWC(GS)) and a modification of the PWC(195) using a 1.17 correction factor and an age and gender- adjusted estimate of resting metabolic rate. Results. The correlations between both submaximal tests and the GXT were significant (p<0.001); however, the correlation between the GXT and the PWC₁₉₅ equation (r=0.807) was higher than the correlation between the GXT and the PWCGs equation (r=0.658). Analysis indicated that the PWC(GS) equation significantly underestimated the VO₂max compared to either the GXT or PWC₁₉₅ (GXT=45.0±7.1, PWC₁₉₅=44.7±6.2, PWC(GS)=42.7±5.8 ml/kg/min; p<0.01). Conclusions. These results suggest that although the gender-specific PWCGs method is easier to compute and may be acceptable, the modified PWC₁₉₅ method is a more accurate estimate of V̇O₂max in children.