This document discusses the social ecological model as it relates to physical fitness and activity. It explains that the individual component is the most influential as it involves psychological factors like interests, needs, desires, and internal/external barriers. Personal factors that influence physical activity for an individual include age, sex, education, abilities, attitudes, motivation, and self-efficacy. Changing an individual's skills, knowledge, attitudes, behaviors, and self-efficacy can impact their physical activity levels. Interventions should focus on making these personal changes.