Development of Walk Tests to Estimate Aerobic Fitness in 10 to 13 Year-Old Children

Abstract

Aerobic fitness is an important indicator of health for children. Estimation of aerobic fitness (VO₂[subscript]max) from field-based tests is an essential aspect of youth fitness tests. Field tests can also provide researchers with more practical ways to examine status or track changes in aerobic fitness than laboratory-based tests. Most fitness tests require a maximal effort from participants. Submaximal walk tests may provide accurate estimates of aerobic fitness and be appropriate for overweight, unfit, or unmotivated children. The accuracy of walk tests to estimate VO₂[subscript]max in young children is not known. Purpose: The purpose of this study was to develop and examine the reliability and validity of quarter-mile, half-mile, and one-mile walk tests for 10-13 year old children. A secondary purpose was to cross-validate previously published walk test equations. Methods: Participants (N = 61) walked one-mile twice on different days with at least 7 days between sessions. Walk times and heart rates were recorded at one-quarter mile, one-half mile, and one-mile distances. Physical activity questionnaires, height, body mass, skinfolds, BODPOD, and maximal treadmill tests were administered. VO₂[subscript]max was directly measured during the treadmill test. Multiple regression was used to develop models to estimate aerobic fitness with and without body mass and self-reported physical activity as predictors. The PRESS-related statistic was used to cross-validate the models. Results: Quarter-mile walk models were slightly more accurate than half-mile or one-mile walk tests. Eight quarter-mile regression models, which can be used for a variety of purposes, were developed. Results showed that heart rate did not add significantly to the prediction of VO₂[subscript]max when body mass was in the model. Removal of heart rate from the model makes test administration substantially more practical because the test user would not have to assess heart rate. Self-reported physical activity added significantly to the prediction of VO₂[subscript]max. The recommended model was: VO₂[subscript]max = 64.481 - (0.143 * body mass [lb]) + (3.930 * Gender [F=0, M=1]) - (3.835 * Quarter-mile Walk Time [min]) + (1.363 * 30-Day Physical Activity Recall), R = .92, standard error of estimate (SEE) = 4.22 ml*kg⁻¹*min⁻¹. The accuracy of the equation was confirmed when cross-validated. Walk times (R[subscsript]xx ~ .90), heart rates (R[subscsript]xx ~ .82), and estimatedVO₂[subscript]max values (R[subscsript]xx ~ .98) were highly reliable over the two test sessions. Cross-validation of previously published walk test equations demonstrated lower correlations with measured VO₂[subscript]max and higher SEEs than the walk tests developed in the present study. Conclusion: The quarter-mile walk tests developed in the present study provide valid estimates of VO₂[subscript]max in young children. The quarter-mile walk tests should be useful for educators and researchers who would like to estimate aerobic fitness from a submaximal field test, particularly in overweight, unfit, or unmotivated young children.