Reliability and validity of the Exercise Self-Regulatory Efficacy Scale^**To request a copy of the Ex-SRES instrument, a one-page summary of its psychometrics and scoring syntax, please send a self-addressed envelope with return postage to the corresponding author. for individuals with chronic obstructive pulmonary disease

Background: Exercise has important benefits for individuals with chronic obstructive pulmonary disease (COPD). However, to sustain long-term benefits of exercise, adherence is needed. Adherence requires self-regulation. No scale is available to measure exercise self-regulation in individuals with COPD. Objectives: We developed and tested the reliability and validity of an "Exercise Self-Regulatory Efficacy Scale (Ex-SRES)" for individuals with COPD. Methods: A convenience sample of 109 subjects with COPD was recruited. Cronbach's alpha was used to assess the internal consistency reliability of the Ex-SRES. Subjects' exercise behaviors and health status were used to assess the validity of the Ex-SRES. Results: The Ex-SRES demonstrated evidence of reliability (Cronbach's alpha .917) and validity (correlation with minutes of exercise per week [r = .41; P < .0001] and health status [r = .37; P < .0001]). Conclusion: The Ex-SRES is a short (16-items) and easy to use questionnaire that may be valuable for assessing patients in clinical settings, as well as for future research studies in behaviors related to exercise.