Predictors of adherence to an Iyengar yoga program in breast cancer survivors

CONTEXT: Despite the known health benefits of physical activity, participation rates in cancer survivor groups remain low. Researchers have attempted to identify alternative modes of nontraditional physical activities that may increase participation and adherence rates. This study investigated the determinants of yoga in breast cancer survivors. AIM: To examine predictors of Iyengar yoga adherence in breast cancer survivors using the theory of planned behaviour. Settings and Design: Classes were held either in Campus Recreation facilities or at the Behavioral Medicine Fitness Center at the University of Alberta in Edmonton, Canada. The study was an evaluation of an existing yoga program. MATERIALS AND METHODS: Twenty-three post adjuvant therapy breast cancer survivors participating in a community-based, twice weekly, 12 week Iyengar yoga program were asked to complete baseline measures of the theory of planned behavior, demographic, medical, health/fitness, and psychosocial variables. Adherence was measured by objective attendance to the classes. STATISTICAL ANALYSIS: We analyzed univariate associations between predictors and yoga adherence with independent t-tests. RESULTS: Adherence to the Iyengar yoga program was 63.9% and was predicted by stronger intention (P<0.001), greater self-efficacy (P=0.003), more positive instrumental attitude (Ps=0.025), higher disease stage (P=0.018), yoga experience in the past year, (P=0.044), diagnosis of a second cancer (P=0.008), lower fatigue (P=0.037), and greater happiness (P=0.023). CONCLUSIONS: Adherence to Iyengar yoga in breast cancer survivors was strongly related to motivational variables from the theory of planned behaviour. Researchers attempting to improve yoga adherence in breast cancer survivors may benefit from targeting the key constructs in the theory of planned behaviour.