A LONGITUDINAL STUDY EXAMINING THE RELATION OF PHYSICAL ACTIVITY ON WEIGHT STATUS DURING ADOLESCENCE

Objective. The objective of this analysis was to examine the relation of physical activity (PA) to weight status in a sample of adolescents. Study Design. A four year longitudinal study was conducted. Methods. A diverse sample of 1098 adolescents aged 11-16 years was assessed annually over four years. Height and weight were measured. BMI and weight status category were calculated. Physical activity was assessed via a questionnaire to determine the hours per week of activity over the past year. A generalized mixed model statistical approach was used to test the main hypothesis. Results. A decline in physical activity and an increase in BMI was found among males and females (p<0.01). Significant differences regarding the amount of physical activity between gender, race and SES levels was also found (p<0.05). Overall, the highest amount of physical activity was reported by males, Caucasians and those in the high SES group. As for weight status, males were more often categorized as "at risk" and "overweight" compared to females (p < 0.05). There was insufficient evidence to support the main hypothesis that physical activity affected weight status. Thus the amount of physical activity one participated in during each study year, did not increase the odds of being categorized as "at risk" or "overweight" compared to a "healthy weight". Nor did the amount of physical activity one participated in during the previous year, increase the odds of being categorized as "at risk" or "overweight" compared to a being categorized as a "healthy weight" the following year. Conclusions. The results of this study do not support the hypothesis that decreasing physical activity during adolescence is related to change in weight status. Conclusions can be made however, regarding the relationships between the covariates and both the amount of physical activity and weight status category. Overall, males, Caucasians and those in the high SES group report higher amounts of physical activity. Males were more often categorized in the higher weight status categories compared to females