Background: A number of obesity studies have been focused on identifying the relationships between socioeconomic status and physical activity involvement. In behavioral medicine, the limited data are available on obese people's physical activity and its related psychological predictors based on psychological theories.
Purpose: To identify the differences in physical activity and its related motivational attributes among normal weight, overweight, and obese adolescents and to find the effect of body mass index (BMI) and the Self-Determination Theory (SDT) constructs in predicting physical activity.
Method: One thousand seventy-one students ranging from seventh to ninth grades were randomly selected from three junior high schools in Seoul (359 normal weight students, 468 overweight students, and 244 obese students). A Korean version of Behavioral Regulation in Exercise Questionnaire-2 and Leisure Time Exercise Questionnaire were applied to measure the participants' motivational attributes and physical activity.
Results: Overweight and obese adolescents showed higher scores on amotivation and externally motivated regulations for physical activity than their normal weight counterparts. Internal regulation was more significant for physical activity in normal weight adolescent. However, there was no difference in physical activity among the three groups. Additionally, the findings identified that BMI and the SDT constructs were significant to explain physical activity.
Conclusion: This study offers fundamental knowledge in gaining a clearer understanding of the types of motivation most likely to contribute to the initiation and promotion of physical activity in overweight and obese adolescents.