title: Using the self-determination theory to understand Chinese adolescent leisure-time physical activity.
abstract: OBJECTIVE
  This study applies the self-determination theory (SDT) to test the hypothesized relationships among perceived autonomy support from parents, physical education (PE) teachers, and peers, the fulfilment of psychological needs (i.e., autonomy, competence, and relatedness), autonomous motivation, and leisure-time physical activity of Chinese adolescents.
  
  
  METHODS
  There are 255 grade six to eight student participants from four middle schools around Shanghai, China included in this study. An accelerometer was used to measure the moderate-to-vigorous physical activity (MVPA). The participants completed the questionnaires regarding SDT variables. The structural equation modelling was applied to examine the hypothesized relationships among the study variables.
  
  
  RESULTS
  The model of hypothesized relationships demonstrated a good fit with the data [X2= 20.84, df = 9, P = .01; CFI = 0.98; IFI = 0.98; SRMR = 0.04; RMSEA = 0.05]. The findings revealed that autonomy support from parents, PE teachers, and peers foster social conditions in which the three basic psychological needs can be met. In turn, autonomy, competence, and relatedness are positively associated with autonomous motivation for MVPA. The autonomous motivation positively relates to the MVPA time of adolescents. The three psychological needs partially mediate the influence of autonomy support from parents (β = 0.18, P < .01; Bootstrap 95% CI = 0.06-0.33) and teachers (β = 0.17, P < .01; Bootstrap 95% CI = 0.03-0.26) in the autonomous motivation.
  
  
  CONCLUSIONS
  In conclusion, these findings support the applicability of SDT in understanding and promoting physical activity of Chinese adolescents.
authors.affiliation: a School of Recreational Sport and Art , Shanghai University of Sport , Shanghai , People's Republic of China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D002648:Child; D002681:China; D015444:Exercise / Q000523:psychology*; D005260:Female; D006801:Humans; D007899:Leisure Activities / Q000523:psychology*; D008297:Male; D008960:Models, Psychological; D009042:Motivation; D010290:Parents; D026684:Personal Autonomy; D010806:Physical Education and Training; D000070777:School Teachers
keywords: Motivation; adolescents; autonomy support; physical activity; psychological needs