Psychological Predictors of Physical Activity and Sedentary Time From Childhood to Adolescence

Objective: Physical activity (PA) declines, while sedentariness increases, in the transition from childhood to adolescence. Factors to prevent such changes need to be identified. External structures for PA decrease with age, and individual characteristics play a more significant role. Prior research has indicated that well-regulated individuals with high perceived athletic competence (PAC) have more PA and less sedentariness. However, whether improvement in these characteristics predicts increased PA and reduced sedentariness in the longer term is unknown and, thus, the aim of the present inquiry. We also test potential age and sex differences. Method: A sample from two Norwegian birth cohorts (analytical sample: n = 858, 51.8% girls) was biennially assessed from age 6 to 18. Accelerometry was used to measure PA and sedentary time. Executive functions (teacher report), effortful control/conscientiousness (parent and self-report), and PAC (self-report) constituted the predictors. A random intercept cross-lagged panel model was applied, which adjusts for unobserved time-invariant confounding effects. Results: Increased conscientiousness predicted increased levels of PA from age 6 to 18 but was unrelated to later changes in sedentary time. Individuals who gained PAC also increased their PA and spent less time on sedentary activities. Changes in executive functions were unrelated to future changes in PA and sedentary time. No age or sex differences were found. Conclusion: Increased conscientiousness and PAC predicted increased PA from childhood to late adolescence. PAC predicted reduced sedentary time. Enhancing conscientiousness and PAC may benefit interventions to promote PA in youth.