Metabolic determinants of 1-mile run/walk performance in children

The 1-mile run/walk test is the field test of choice for evaluating maximal aerobic power (VO2max) in school-aged children. The objective of this study was to determine the relative importance of selected metabolic determinants of mile run/walk performance in children 6-14 yr of age. Mile run/walk time (MRWT), VO2max, running economy (VO2 in ml.kg-1.min-1 at 8.05 km.h-1; VO2econ), and the percentage of VO2max utilized at the average mile run/walk speed (%VO2max) were measured in 59 children (33 boys and 26 girls); 27 6-8 yr olds (group 1), 17 9-11 yr olds (group 2), and 15 12-14 yr olds (group 3). Partial correlations between MRWT and VO2max, VO2econ, and %VO2max, holding constant the effects of age and sex, were as follows: group 1: -0.26, 0.03, and -0.82; group 2; -0.43, 0.09, and -0.88; and group 3, -0.60, 0.45, and -0.80. Multiple regression analysis indicated that the combination of the three metabolic measures accounted for 90%, 97%, and 90% of the variance in MRWT in the three age groups, respectively. Standardized regression coefficients for VO2max, VO2econ, and %VO2max in group 1 (-0.66, 0.19, and -0.83), group 2 (-0.45, 0.33, and -0.92), and group 3 (-0.76, 0.27, and -0.50) indicated that the %VO2max utilized at the average mile run/walk speed was the most important determinant of MRWT variance in children 6-11 yr old, whereas VO2max was the most important determinant for children 12-14 yr old. We conclude that the relative importance of the metabolic determinants of the 1-mile run/walk test, as typically administered in the schools, changes with age.