Obesity, cardiovascular fitness, and physically active adolescents' motivations for activity: A self-determination theory approach

Objectives: Overweight and obesity pose significant health problems for adolescents. Rates of overweight and obesity in children have increased 45% in the last decade and have increased three-fold since 1980. Because children who are physically active are at lower risk for the development of obesity, it is important to understand some of the factors that influence children's physical activity patterns. The purpose of this study was to examine the relationship between motivation, cardiorespiratory fitness, and weight status, defined as obese or non-obese. We predicted that the association between motivation and weight status would become non-significant when controlling for cardiorespiratory fitness. Design: The study employed a correlational, cross-sectional design. Method: Participants included physically active middle school students (N = 82.51% female) of aged 12-14 years, who participated in the Teen Eating and Activity Mentoring in Schools (TEAMS) study aimed at improving health and preventing obesity among middle school students. Students completed attitudinal questionnaires about physical activity and self-determination on a computer-based system and participated in a number of fitness performance, health behavior, and anthropometric assessments. Results: Non-obese adolescents showed higher intrinsic motivation scores than obese adolescents. Mediational analyses showed that cardiorespiratory fitness mediated the relationship between motivation and weight status. Conclusions: The results of this study demonstrate differences in physical activity motivation as a function of adolescent weight status, but only for intrinsic motivation. As predicted, adolescents who were intrinsically motivated for physical activity were more fit and thereby less likely to be obese. The findings are consistent with self-determination theory. (C) 2011 Elsevier Ltd. All rights reserved.