Exercise and VO_2max in Children: A Meta-Analysis

Abstract

Despite widespread belief that children are aerobically trainable, studies examining the ability of a child to improve maximal oxygen uptake (VO_2max) have yielded inconsistent findings. The present investigation, using meta-analysis, examined the effects of physical activity, gender, experimental design, and sufficiency of exercise on the VO_2max of child subjects. Sixty-nine studies examining the effects of training on children were originally located; 28 met criteria for inclusion. From these studies, 70 effect sizes (ESs) were calculated. Some studies employed cross-sectional (XS) designs involving comparisons of intact groups of subjects; the others used a pretest-posttest (PP) design, which followed subjects throughout a specified training program. Average ES indicated a considerable difference between trained and untrained subjects though several possible sources of confounding (e.g., subject self-selection) in XS studies were identified. Effect sizes of. 94 (±1.00) and .35 (±0.82) were achieved for XS and PP designs, respectively. Further analyses were conducted with the PP design studies. In these studies, subjects improved approximately 2 ml-kg¹ min⁻¹. In the PP studies, effect sizes were not significantly affected by (a) gender, (b) “sufficient” and “insufficient” training protocol, or (c) test mode. Results indicated that reported changes in VO_2max in children are small to moderate and are a function of the experimental design used.

Key Words:

• aerobic capacity
• aerobic fitness
• cardiovascular fitness
• children
• growth and development