Tracking of health-related fitness components in youth ages 9 to 12.

Abstract

The purpose of this study was to examine the tracking of multiple health-related fitness components in children from fourth to sixth grade. A battery of fitness tests was used to measure 414 children (213 boys, 201 girls, mean = 9.48 yr, +/- 0.41) from three elementary schools in Southern California. Children were assessed during the fall and spring of each grade. Baseline scores were correlated (Spearman) with each subsequent time point. For boys 3-yr correlations of body mass index (BMI) (0.89), skinfold thickness (0.80), sit-and-reach test (0.67), and the pull-up test (0.66) indicated high levels of tracking. Mile run (0.56), sit-up test (0.46), and waist-to-hip ratio (0.30) tracked moderately. For girls BMI (0.83), sum of skinfolds (0.75), sit-and-reach test (0.72), and the pull-up test (0.63) tracked highly, while mile run (0.42), sit-up test (0.47), and waist-to-hip ratio (0.42) tracked moderately. Results suggest that relative rankings of BMI, skinfold thickness, and sit-and-reach test performance are more likely to track during early adolescence. Measures of cardiovascular fitness, muscular strength, and endurance and fat distribution may be less likely to track into adolescence, possibly because they are more influenced by changes in physical activity or because tracking may be reduced by measurement error.