Exploring The Link Between Exercise Identity And Intervention Dosage

Abstract

Adolescent overweight and obesity in the United States has increased in past decades, resulting in numerous physiological and psychological consequences. Obesity interventions often aim to increase physical activity (PA). Such interventions may strengthen Exercise Identity (EI). A strong EI has been positively related to long-term PA engagement, as individuals seek to engage in behaviors congruent with the role identity of “exerciser.” Greater dosage of PA intervention may progressively increase EI, and enhance future exercise behavior. However, the relationship between PA intervention dosage and EI in an overweight and obese adolescent population is unclear. PURPOSE: To determine if a PA intervention, when delivered in varying dosages, may strengthen an overweight or obese adolescent’s EI. METHODS: Fifty overweight and obese adolescents (age=14.16 ± 1.88 years, BMI=35.66 ± 7.87 kg/m2, BMI percentile=97.5% ± 3.7%) were recruited from a behavior change summer camp, which included a PA intervention component. Age, gender, height, and weight were collected, and BMI was calculated. The participants were categorized into three separate groups, according to length of PA intervention (dosage): 3 week PA dosage, 4-5 week PA dosage, and 6-7 week PA dosage. Participants completed the Anderson Exercise Identity Scale and 3 Day Physical Activity Recall (3DPAR) at pre- and post-intervention. Group comparisons of EI were made using two-way ANOVA. Changes in vigorous physical activity (VPA) within groups were calculated using Log-Rank, Kaplan-Meier, and Wilcoxon. Activities on the 3DPAR were categorized and coded to compare exercise behavior within groups. RESULTS: Upon comparison, the mean EI in the 6-7 week intervention group significantly differed from other group means and resulted in a significant increase in EI within groups (p<0.001). All intervention groups demonstrated significant increases in VPA (p<0.05), and complied with National PA Guidelines of 60+ minutes of MVPA daily; VPA performed on at least 3 days/week. CONCLUSION: Exercise Identity may be increased in overweight and obese adolescents following a physical activity intervention. Greater dosage of physical activity intervention will result in greater benefits to Exercise Identity, and may ultimately enhance long-term exercise behavior.