Development of an instrument to measure adherence to strength training in postmenopausal breast cancer survivors

Purpose/Objectives: To develop a theory-based instrument for assessing barriers and motivators to strength- or weighttraining exercise (SWTE) in postmenopausal breast cancer survivors with measurable bone loss after treatment. Design: Exploratory, descriptive, and methodologic. Setting: Academic oncology clinics in the midwestern United States, homes, and a fitness center. Sample: 85 women, predominantly Caucasian (99%), breast cancer survivors, aged 35-75 years, six months after treatment, who were enrolled in a larger study were randomized to receive SWTE; 65 completed the instrument. Methods: Development of a 47-item Likert-type instrument using interviews, contributions from experts, published research, and Self-Efficacy Theory. Main Research Variables: Barriers and motivators of adherence to SWTE. Findings: Four subscales emerged that accounted for 26%-59% of the variance. Factor subscales for barriers were "not prioritizing time for self" and "overcoming other barriers to adherence." Subscales for motivators included "education and feedback" and "social support." Conclusions: The final instrument contained 47 items dispersed across four subscales. Additional psychometric testing of the instrument with a larger population is indicated. Implications for Nursing: Nurses and healthcare professionals may use the instrument to readily identify barriers and motivators to SWTE adherence to improve program design and implementation efforts aimed at facilitating enhanced exercise adherence in breast cancer survivors with measurable bone loss after treatment.