Negative Physical Self-Concept is Associated to Low Cardiorespiratory Fitness, Negative Lifestyle and Poor Mental Health in Chilean Schoolchildren

Background: Evidence suggests that physical self-concept (PSC) is linked to well-being in children and adolescents. Objective: The objective was to investigate the association of PSC with mental health (i.e., depression and body image), physical status (i.e., fitness and weight status) and lifestyle (physical activity (PA) patterns and nutritional level) in Chilean schoolchildren. Methods: A total of 617 schoolchildren (n = 271 girls and n = 346 boys) aged 10–14 years participated in this study. Self-concept, depression and body image dissatisfaction were determined by questionnaires. Physical fitness, PA, screen time (ST), Mediterranean diet (MD) adherence and anthropometric parameters were also included. Results: Poor PSC was linked to bad cardiorespiratory fitness (CRF) (<42 VO2max) (OR 1.64; 95%CI 1.12–2.34; p = 0.01), severe body image dissatisfaction (OR 2.51, 95%CI 0.99–6.35; p = 0.05), ST of more than two hours a day (OR 2.1; 95%CI 1.41–3.12; p < 0.001), PA after school of no more than two hours per week (OR 1.52; 95%CI 1.08–2.13; p = 0.015) and depression (OR 1.80; 95%CI 1.1–2.92; p = 0.017). High nutritional level showed an association with general PSC and general self-concept (p < 0.05). Absence of body image dissatisfaction was related to general self-concept (p < 0.01) and physical condition dimensions (p < 0.05). Conclusions: PSC is associated with CRF, PA after school, ST and nutritional level. According to mental health variables, poor PSC is related to depression in Chilean schoolchildren. Therefore, promoting a healthy lifestyle among children should be a target of community- and school-based interventions to promote PSC.