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This research used meta-analysis to examine the effect of resistance training on children and youth. Studies investigating the effects of various forms of resistance training in participants of ages less than 18 years were analyzed. Effects sizes (ES) were calculated by gender, age group (boys ages > or = 16 years and girls ages > or = 14 years were defined as older), training (isokinetic, isometric, isotonic), and design type (pretest-posttest or experimental-control). Similar ESs were obtained for older and younger children; isotonic methods demonstrated larger ESs than isometric or isokinetic. Larger ESs were obtained in studies with cross-sectional (experimental-control) than pre-post designs. Resistance training appears to enhance muscular endurance and strength in children and youth. The magnitude of the effect appears to be a function of gender, training method, and experimental design.

Despite widespread belief that children are aerobically trainable, studies examining the ability of a child to improve maximal oxygen uptake (VO2max) 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 VO2 max 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.kg 1 x 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 VO2max in children are small to moderate and are a function of the experimental design used.

Obesity is a major concern in the aging population and degrades health, motor functions and cognition in older adults. The effects of obesity are pervasive and challenging to health-care systems, making this a widespread and critically important public health dilemma. In this review, we examine the relationship between obesity, cognitive aging, and related dysfunctions. Potential neural mechanisms underlying such relationship are described. We propose that cost-effective exercises can be employed to cope with obesity and cognitive declines in older adults. Finally, we discuss implications and future research directions.