Maximal oxygen uptake versus maximal power output in children

Maximal oxygen uptake ([Vdot]O2max) is considered the optimal method to assess aerobic fitness. The measurement of [Vdot]O2max, however, requires special equipment and training. Maximal exercise testing with determination of maximal power output offers a more simple approach. This study explores the relationship between [Vdot]O2max and maximal power output in 247 children (139 boys and 108 girls) aged 7.9-11.1 years. Maximal oxygen uptake was measured by indirect calorimetry during a maximal ergometer exercise test with an initial workload of 30W and 15Wmin-1 increments. Maximal power output was also measured. A sample (n=124) was used to calculate reference equations, which were then validated using another sample (n=123). The linear reference equation for both sexes combined was: [Vdot]O2max (mlmin-1)=96 + 10.6maximal power + 3.5body mass. Using this reference equation, estimated [Vdot]O2max per unit of body mass (mlmin-1kg-1) calculated from maximal power correlated closely with the direct measurement of [Vdot]O2max (r=0.91, P0.001). Bland-Altman analysis gave a mean limits of agreement of 0.22.9 (mlmin-1kg-1) (1s). Our results suggest that maximal power output serves as a good surrogate measurement for [Vdot]O2max in population studies of children aged 8-11 years