| Summary |
In recent decades, the prevalence of youth obesity has been on the rise (Ogden et al, 2010) highlighting the need for research evaluating interventions targeting eating behaviors and lifestyle activity. Although it is important to examine the impact of interventions on physical activity, fitness, and body composition given their relationship with physical health, it is also important to assess the impact of interventions on mental well-being. Self-perceptions, including self-esteem, are important indicators of mental well-being (Blaine et al., 2006). In fact, Biddle (2011) found poor self-perceptions to be a predominant mental health issue in overweight adolescents. Although exercise is associated with improved self-esteem, the changes in self-esteem are often not large in magnitude (Spence et al., 2005). The greatest improvements are likely to occur in those populations that would benefit the most such as overweight individuals (Lox, Ginis, & Petruzzello, 2010). In addition to exercise, mentoring programs have also had positive effects on youth self-esteem (King, 2002). Thus, exercise combined with mentoring may by an effective strategy for enhancing self-perceptions. This study evaluated the impact of a mentor-based exercise program on the self-perceptions, body composition, physical activity, and fitness level of overweight adolescents. Adolescents participated in mentor-led, weekly exercise sessions for approximately 14 weeks. The program also involved a lifestyle-coaching component through weekly behavioral challenges designed to enhance self-regulatory skills related to physical activity and healthy eating. To date, 28 participants with a mean age of 14 and a baseline BMI of 32 have participated in the mentoring intervention. An additional 12 adolescents were randomly assigned to a wait-list control condition. In addition to fitness (maximum treadmill test), physical activity (accelerometers) and body composition (DXA) assessments, participants completed a questionnaire that examined exercise specific self-perceptions, physical self-worth, and global self-esteem (Whitehead, 1995; Harter 1988) pre/post intervention and after a no treatment maintenance period. A series of 2 (condition) X 2 (time) repeated measures ANOVA's combined with effect size inspection revealed that participants in the mentoring condition showed improved aerobic fitness (d = .44) compared to the control condition, which exhibited a negative change (d = -.06). Participants in the mentoring condition showed increased moderate-vigorous intensity activity (d = .41), compared to the control group (d = .14). While BMI-Z score improvements did not differ across conditions, percent body fat change for the experimental group showed a small, positive change (d = .22), compared to the control group (d = .08). In terms of self-perceptions, mentor participants reported improved self-esteem, physical self-worth, and perceived physical condition with the effect sizes being in the moderate to large range (i.e., d = .52, .79, .82), while the control group showed minimal change (i.e., d = .11, .26, .30). However, when evaluated after a no contact follow-up period, all variables in the experimental condition had regressed toward baseline. These results suggest a mentor-based exercise intervention has a positive impact while adolescents are in the program. However the program does not seem to be effective at helping participants maintain healthy changes when the program ends. |
