Moderating Role of Physical Fitness in the Association Between TV Time and Adiposity Parameters in Adolescents.

Purpose: To identify whether physical fitness (PF) components play a moderating role in the relationship between TV time and adiposity levels.

Design: Cross-sectional study.

Setting: Few studies have examined if different PF levels modify the association between TV time and adiposity in adolescents. Studies often focus on the isolated relationships between obesity and TV time, or obesity and PF levels.

Subjects: 1071 adolescents (617 girls), aged 12 to 17 years.

Measures: Cardiorespiratory fitness (CRF), abdominal muscular endurance, and lower limb strength were evaluated using the protocols of the fitness testing battery. TV time was obtained using a self-reported questionnaire. Body mass index (BMI) and waist circumference (WC) were also assessed. Moderation analyses were conducted through multiple linear regression models with the following associations tested in different models: PF components, TV time, and interaction (PF component x TV time) with adiposity parameters (BMI and WC).

Results: A significant interaction term was found for CRF and TV time in the association with both WC (β: -.005; 95% CI: -.009; -.001; = .012) and BMI (β: -.002; 95% CI: -.004; -.001; = .009).

Conclusion: CRF moderates the relationship between TV time and adiposity measures in this cross-sectional analysis. These data support strategies looking at increasing physical activity levels to improve CRF and avoid the development of excess abdominal obesity and excess weight.