Perceived Exercise Self-efficacy as a Predictor of Exercise Behavior in Individuals Aging with Spinal Cord Injury

Kroll T, Kratz A, Kehn M, Jensen MP, Groah S, Ljungberg IH, Molton IR, Bombardier C: Perceived exercise self-efficacy as a predictor of exercise behavior in individuals aging with spinal cord injury. Am J Phys Med Rehabil 2012;91:640Y651. Objective: The purpose of this study was to test the hypothesized association between exercise self-efficacy and exercise behavior, controlling for demographic variables and clinical characteristics, in a sample of individuals with spinal cord injuries. Design: A cross-sectional national survey of 612 community-dwelling adults with spinal cord injury in the United States ranging from 18 to 89 yrs of age was conducted. Sample consisted of 63.1% men with a mean (SD) duration of 15.8 (12.79) yrs postinjury; 86.3% reported using a wheelchair. Results: Self-efficacy was the only independent variable that consistently predicted all four exercise outcomes. Self-efficacy beliefs were significantly related to frequency and intensity of resistance training (R-2 change = 0.08 and 0.03, respectively; P < 0.01 for all) and aerobic training (R-2 change = 0.07 and 0.05, respectively; P < 0.01 for all), thus explaining between 3% and 8% of the variance. Hierarchical linear regression analysis revealed that controlling for other demographic and physical capability variables, the age-related variables made statistically significant contributions and explained between 1% and 3% of the variance in aerobic exercise frequency and intensity (R-2 change = 0.01 and 0.03, respectively; P < 0.01 for all). Clinical functional characteristics but not demographic variables explained participation in resistance exercise. Conclusions: Self-efficacy beliefs play an important role as predictors of exercise. Variations in exercise intensity along the age continuum have implications for exercise prescription and composition. Future research should replicate findings with objective activity measures.