Sedentary behavior and physical activity predicting depressive symptoms in adolescents beyond attributes of health-related physical fitness

Background: Sedentary behavior (SB), physical activity (PA), and attributes of physical fitness have been shown to be related to depressive symptoms in adolescents. The purpose of the present study was to investigate whether SB and fitness -producing activity predicted depression in active adolescents over and above gender and fitness attributes. Methods: Participants were 249 adolescents (age: 12.85 +/- 0.89 years, mean +/- SD) from 3 public middle schools who wore Actical accelerometers to assess their SB and PA. Participants also completed the FITNESSGRAM health-related fitness assessment and a brief depression questionnaire. A 3-step hierarchical regression analysis was conducted with gender and fitness attributes (i.e., body mass index (BMI), maximal volume oxygen uptake (VO2max), curlups, and pushups), moderate- and vigorous-intensity activity, and SB entered in respective steps. Results: Regression analysis indicated activity variables (i.e., moderate- and vigorous-intensity activity) significantly predicted depression (Delta R-2= 0.12, p < 0.01) beyond gender and fitness attributes. Overall, gender, fitness attributes, activity variables, SB explained 31% of the variance in depression. Structure coefficients revealed VO2max (r(s) = -0.77), moderate-intensity activity (r(s) = -0.67), vigorous-intensity activity (r(s) = -0.81), and SB (r(s) = -0.57) were substantially correlated with the criterion variable; thus, they were the strongest predictors of depression. Conclusion: The findings of the current study indicated SB and PA were both significant predictors of depression; however, sufficient fitness producing activity and adequate cardiorespiratory fitness may nullify the negative influence of SB on depressive symptoms in active adolescents. (C) 2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license.