Is objectively measured physical activity related to behavioural and emotional difficulties in adolescents?:evidence from ALSPAC

Objectives: To examine whether behavioural and emotional problems are associated with total volume of physical activity (PA) and/or moderate-to-vigorous intensity PA (MVPA) in adolescents.Design: An observational analysis of data from a large birth cohort.Method: 5593 participants (47.6 per cent boys) from the Avon Longitudinal Study of Parents and Children (ALSPAC) had valid accelerometer measurements of PA at age 11. PA was recorded as average counts-per-minute (cpm) and as minutes/day in MVPA. At 11 years parents completed the Short Moods and Feelings questionnaire (SMFQ) to assess their child’s depressive symptoms. This was completed by participants themselves at 13. Behavioural problems were described at 11 and 13 using the Strengths and Difficulties Questionnaire (SDQ).Results: Regression analyses found that in girls, cpm at 11 predicted depressive symptoms at 13 (b=–0.12, 95% CI =–0.19 to –0.04) and MVPA at 11 predicted depressive symptoms at both 11 (b=–0.11, 95% CI=–0.20 to –0.02) and 13 (–0.09, 95% CI=–0.18 to –0.01); this relationship did not hold for boys. Furthermore, cpm and MVPA were negative predictors of the emotional symptoms and peer problems scales of the SDQ but were positively associated with the conduct problems, hyperactivity and prosocial behaviour scales.Conclusions: These findings suggest a positive impact of PA on adolescent’s well-being, although gender differences were identified. Further analysis is exploring the role of confounding variables and ‘dose’ necessary to protect against depressive and behavioural symptoms. These findings may have important implications for physical activity research and health policy.