Objective: To determine, through the use of a structural equation model, the relationships that exist between physical activity, body fat, perceived physical ability, and three indicators of psychological well-being, in a sample of Spanish university students.
Methods: A descriptive cross-sectional study of 639 students 18-29 years of age representative of the universities of Valencia, Spain, during the 2005-2006 term. Physical exercise was rated by taking an inventory of healthy behaviors among students. The following scales were applied: self-perceived physical ability, self-esteem, satisfaction with life, and subjective vitality. Body fat was expressed as the percentage of fat mass (PFM). A theoretical model was devised using six measured variables.
Results: The participants' level of physical activity was moderate; they perceived themselves to be physically competent; had high self-esteem; were satisfied with life; and had high vitality. Physical activity was negatively correlated with PFM in men and women alike; and negatively associated with perceived physical ability; while perceived physical ability was positively associated with self-esteem, life satisfaction, and subjective vitality. The effect of physical activity on perceived competence was mediated in part by PFM in men. In women, exercise was directly correlated to PFM, as well as perceived ability, without PFM mediation.
Conclusions: Increased physical activity is of great value to public health because, in addition to helping to reduce body fat, it improves psychological well-being and self-image.