title: Longitudinal study of the number and choice of leisure time physical activities from mid to late adolescence: implications for school curricula and community recreation programs.
abstract: BACKGROUND
  Physical activity (PA) declines during adolescence. There has been little research describing this decline or examining participation and nonparticipation in specific activities.
  
  
  OBJECTIVE
  To describe the pattern of change in the number of physical activities, the time spent on specific activities, and the stability of participation and nonparticipation in specific activities during adolescence.
  
  
  METHODS
  A population-based 4-year longitudinal study of adolescents recruited from a single suburban school district near Pittsburgh, Pa.
  
  
  METHODS
  A total of 782 adolescents, aged 12 to 15 years at baseline.
  
  
  METHODS
  Physical activity was measured annually via questionnaire. Outcome measures include hours per week of PA, number of reported activities, and participation (yes or no) in specific activities.
  
  
  RESULTS
  Physical activity declined during the 4 years by 26%. The decline in PA was primarily due to a decrease in the number of reported activities. Adolescents who continued to report an activity during the 4 years of the study maintained or increased the time spent on that specific activity. Female adolescents were more likely to report individual activities, while male adolescents were more likely to report team activities. The probability of maintaining participation in a specific activity during the 4 years was low to moderate, 0.02 to 0.47 for female adolescents and 0.04 to 0.71 for male adolescents. The probability of not participating in a specific activity during the 4 years was extremely high and consistent for male and female adolescents, 0.70 to 1.00.
  
  
  CONCLUSIONS
  The decline in PA during adolescence is primarily due to a decrease in the number of activities in which the adolescent is participating, and there is only a moderate probability that an adolescent will continue to participate in an activity during the 4-year period from junior to senior high. Future efforts should be directed at identifying factors associated with initiating and maintaining participation in specific activities.
authors.affiliation: Department of Health and Physical Education, School of Education, University of Pittsburgh, PA 15261, USA. debaaron@pitt.edu
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Aaron
authors.forename: Kristi L
authors.initials: KL
authors.lastname: Storti
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Robertson
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Kriska
authors.forename: Ronald E
authors.initials: RE
authors.lastname: LaPorte
mesh_terms: D000293:Adolescent / Q000502:physiology*; D000367:Age Factors; D000704:Analysis of Variance; D002648:Child; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012044:Regression Analysis; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013997:Time Factors