Associations between Physical Activity Motives and Trends in Moderate-to-Vigorous Physical Activity Among Adolescents Over Five Years.
Abstract BACKGROUNDMotives for participation in physical activity (PA) have been associated with moderate-to-vigorous intensity PA (MVPA); however, these associations have yet to be established during the transition from childhood to adolescence. This study examined the longitudinal associations between five PA motives (i.e., enjoyment, competence, fitness, social, and appearance) and MVPA over a 5-year period spanning late childhood (9-11 years), early adolescence (12-14 years), and middle adolescence (15-16 years). METHODSSelf-report data (n = 937) were drawn from the ongoing Monitoring Activities for Teenagers to Comprehend their Habits study. The Motives for Physical Activity Measure-Revised (MPAM-R) questionnaire was used to measure PA motives. MVPA was assessed with an empirically supported 2-item measure developed specifically for adolescents. Data from three times points per school year over 5 years (resulting in 15 survey cycles) were analyzed using sex-stratified mixed effects regression models after establishing longitudinal measurement invariance for the MPAM-R.RESULTSMVPA increased from cycle 1 (9-11 years) to 7 (11-13 years) for girls and from cycle 1 (9-11 years) to 9 (12-14 years) for boys before decreasing for both sexes through to cycle 15 (14-16 years). Longitudinal measurement invariance was established for a 22-item version of the MPAM-R. For boys, enjoyment and competence motives were positively associated with MVPA from late childhood to middle adolescence and fitness motives were negatively associated with MVPA from late childhood to middle adolescence. For girls, enjoyment motives were positively associated with MVPA during late childhood and competence motives were positively associated with MVPA from late childhood to middle adolescence. CONCLUSIONSPA interventions should aim to increase enjoyment during PA and provide opportunities for children and adolescents to develop a desire to build competence during PA. PA interventions targeted to youth should avoid promoting the desire to be active to improve fitness, particularly among boys.