Description of sport participation profiles and transitions across profiles during adolescence.

Few studies describe sport participation profiles in the general population using multiple characteristics. Therefore, the objective of this study was to identify sport participation profiles during adolescence and to describe transitions across profiles from grades 5 to 12 (age 10 to 18 years). We used data from 916 participants (55% girls; age 10-12 years at inception) of the Monitoring Activities of Teenagers to Comprehend their Habits (MATCH) study. Participants self-reported involvement in 36 organized and unorganized physical activities three times/year from grades 5 to 12 (24 data collection cycles; 2011-2018). At each school grade, we derived four categorical variables of sport involvement: number of organized sports, number of unorganized activities, weekly sessions, and number of year-round activities. To identify sport participation profiles, we used latent class analysis at each grade. To characterize transitions between sport participation profiles across grades, we used latent transition analysis. Five distinct sport participation profiles emerged: "non-participants", "unorganized activities only", "single-sport low frequency", "single sport high frequency", and "multi-sport". Only "multi-sport" participants were unlikely to be classified as "non-participants" over time. Encouraging multi-sport participation might help protect against later non-participation. This study helps identify important times to intervene for improving physical activity levels.