Abstract
OBJECTIVES: This study aimed to (1) develop a new measure of adherence to exercise for musculoskeletal (MSK) pain (Adherence To Exercise for Musculoskeletal Pain Tool: ATEMPT) based on previously conceptualised domains of exercise adherence, (2) report the content and structural validity, internal consistency, test-retest reliability, and measurement error for the ATEMPT outcome measure in patients managed with exercise for MSK pain. METHODS: ATEMPT was created using statements describing adherence generated by patients, physiotherapists and researchers, with content validity established. Baseline and retest questionnaires were distributed to patients recommended exercise for MSK pain in 11 National Health Service physiotherapy clinics. Items demonstrating low response variation were removed and the following measurement properties assessed: structural validity, internal consistency, test-retest reliability and measurement error. RESULTS: Baseline and retest data were collected from 382 and 112 patients with MSK pain, respectively. Confirmatory factor analysis established that a single factor solution was the best fit according to Bayesian Information Criterion. The 6-item version of the measure (scored 6-30) demonstrated optimal internal consistency (Cronbach's Alpha 0.86, 95% CI 0.83 to 0.88) with acceptable levels of test-retest reliability (intraclass correlation coefficient 0.84, 95% CI 0.78 to 0.88) and measurement error (smallest detectable change 3.77, 95% CI 3.27 to 4.42) (SE of measurement 2.67, 95% CI 2.31 to 3.16). CONCLUSION: The 6-item ATEMPT was developed from the six domains of exercise adherence. It has adequate content and structural validity, internal consistency, test-retest reliability and measurement error in patients with MSK pain, but should undergo additional testing to establish the construct validity and responsiveness.