Differential relationship between subjectively and objectively measured physical activity and psychosocial correlates of physical activity in rural youth

Purpose: To examine the relationship between psychosocial and environmental correlates of physical activity (PA) and levels of PA measured by self-report and accelerometry.

Methods: A total of 115 youth (57% female, mean age 13.8 years) recruited from fourth, eighth, and eleventh grades in two rural counties in Georgia participated in the study. Participants were given a battery of physical assessments including anthropometric measurements, hemodynamics, blood lipids, and physical fitness. Participants also completed a self-report of PA and questionnaires assessing social support for PA, self-efficacy for PA, and perceptions of neighborhood environment. Participants also wore accelerometers for a minimum of four days.

Results: Self-reported PA was significantly correlated with physical fitness (r = .23, p < .05), social support for PA (r = .42, p < .01), and self-efficacy for PA (r = .35, p < .01). Objectively measured PA (via accelerometry) was only significantly correlated with waist circumference (r = -.24, p < .01), physical fitness (r = .64, p < .01), BMI (r = -.29, p < .01), and neighborhood violence (r = -.25, p < .01). The correlation between self-reported PA and accelerometer-based PA was r = .39 (p < .01).

Conclusions: The relationships between physical activity and PA correlates varied as a function of the method used to quantify physical activity in rural youth.