Longitudinal studies from childhood through adolescence have the potential of defining maturational changes in cardiovascular risk factors and may provide insight into the prediction of future cardiovascular disease. We assessed aerobic fitness, muscular strength, vigorous and sedentary activity, maturation, blood pressure, lipids, and body composition in 125 healthy children for a period of five years (mean baseline age, 10.5 years). All subjects were in pre- or early-puberty at baseline. After adjusting for age and gender and considering the confounding effects of growth and maturation, we examined whether changes in fitness and activity during the first four years of our study could predict cardiovascular health outcomes at year-five of our study. Change in muscular strength explained 4 % of the variability in year-five systolic blood pressure. Change in aerobic fitness explained 11 % of year-five total cholesterol to high density lipoprotein ratio and 5 % of year-five low density lipoprotein cholesterol. Changes in aerobic fitness and muscular strength explained 15 % of the variability in year-five adiposity and 15 % of the variability in year-five abdominal adiposity. Childhood health promotion programs that specifically target increases in physical fitness may help to reduce the increasing prevalence of adolescent obesity.