Background: Early adolescence is developmental period when youth begin to shift exercise and physical activity patterns toward increased sedentary living. The major causes and contributing factors to this change are poorly understood. This study examines the relationship between sociodemographic factors, behavioral and family factors that influence physical activity patterns of middle grades students. Methods: The 1578 youth ranged in age from 12 (22%) to 13 (78%) and were divided between white (65%), African American (19%), and Hispanic (16%) subpopulations, with 37% overall qualifying for reduced-price or free school lunches. The assumptions for Analysis of Covariance versus Analysis of Variance (ANOVA) were examined, with the final results reported separately for attitudes toward exercise as predictors and sociodemographic variables and measures of family functioning as predictors. Results: Positive attitudes were more strongly associated than were negative attitudes with exercise. Of the categorical predictors, student gender and family involvement with fitness had the most statistically significant associations with self reported exercise (6 for gender and 5 for family involvement with fitness). Conclusions: The results of this analysis of a diverse and large sample of young adolescents are placed in the context of family leisure and work time in our "hurried" culture.