Psychosocial correlates of physical activity in healthy children

Background: Understanding the determinants of physical activity in children is critical for the treatment and prevention of childhood obesity. Social- cognitive theory has been used to understand behavioral patterns in childre n. Objectives: To explore the relationship between health beliefs, self-effica cy, social support, and sedentary activities and physical activity levels i n children and to examine the relationship between physical activity and ch ildren's self-esteem. Methods: Ninety-two children aged 10 to 16 years completed the study. Physi cal activity was monitored for 1 week with a motion detector (Actitrac; IM. Systems, Baltimore, Md). Moderate-level activity and high-level activity w ere defined based on the results of treadmill testing. Health beliefs, self -efficacy, social influences, and time spent in sedentary behaviors were de termined through questionnaires. Self-esteem was measured using the Piers-H arris Children's Self-Concept Scale. Chronic anxiety was measured with the Revised Children's Manifest Anxiety Scale. Results: There was a significant decline in physical activity levels betwee n ages 10 and 16 years, particularly in girls. Preteen girls spent approxim ately 35% more time in low- and high-level activity than did teenage girls (P<.001). Overall, children spent 75.5% of the day inactive, with a mean+/- SD of 5.2+/-1.8 hours watching television, sitting at the computer, and doi ng homework. In contrast, only 1.4% of the day (12.6+/-12.2 minutes) was sp ent in vigorous activity. Time spent in sedentary behaviors was inversely c orrelated with the amount of moderate-level activity (P<.001) but not high- level activity. In contrast, time spent in high-level activity correlated w ith self-efficacy scores (P<.001) and social influences scores (P<.005). Hi gh-level physical activity was also associated with improved self-esteem (P <.05). Higher health beliefs scores were not correlated with physical activ ity levels. Conclusions: Children and adolescents are largely sedentary. Correlates of high- and low-level physical activity are different. Time spent on sedentar y activities is inversely correlated with moderate-level activity, while se lf-efficacy and social influences are positively correlated with more inten se physical activity. In addition, increased high-level physical activity i s an important component in the development of self-esteem in children.