Effect of a physical activity intervention on individual pattern of daily self-efficacy in women with breast cancer and psychological distress

Self-efficacy, which is a key determinant of physical activity (PA), fluctuates in a specific way for each individual and is influenced by emotional or physiological states. However, studies have only investigated the temporal variability of self-efficacy at the between-person level and excluded people with severe psychological distress, whereas depressive and anxiety symptoms could have a negative effect on self-efficacy patterns. We examined the effects of a 12-week PA intervention on daily self-efficacy level among women with breast cancer and psychological distress. Series of N-of-1, with an ABA’ design, were carried out. Phase A and A’ (2 weeks each) represented pre- and post-intervention measures. During the 16 weeks of the study, sixteen participants daily reported their self-efficacy, depression, and anxiety levels. A significant increase of self-efficacy for PA has been found for 9 participants during and/or after the intervention phase. Different temporal patterns of self-efficacy were observed during those phases.