Abstract
PROM: The Chinese version of the Adult Sedentary Behavior Reduction Intention Questionnaire, a 16-item self-reported tool based on the Theory of Planned Behavior (TPB), was developed to assess adults' intentions to reduce sedentary behavior. MEASUREMENT PROPERTY: Internal consistency is used to measure the reliability of the questionnaire, while content and structural validity are studied to assess its validity. DESIGN: A mixed-methods exploratory sequential design with two phases. SAMPLE: Adults aged over 18 years diagnosed with coronary heart disease, with a total daily sedentary time exceeding 6 h, normal cognitive function, and willingness to participate in the study were included. METHODS: The study was conducted in two phases. In Phase 1, an initial item pool was developed through a literature review and refined using two rounds of Delphi expert consultation. Expert positivity, authority levels (Cr), coefficients of variation (CV), and Kendall's W coefficient were calculated to assess representativeness, credibility, and consensus. A pilot study evaluated face validity and finalized the scale. In Phase 2, a cross-sectional study involving 316 participants was conducted to assess psychometric properties. Reliability was evaluated using Cronbach's α and split-half reliability, while content validity was assessed using the content validity index (I-CVI). Construct validity was examined through confirmatory factor analysis (CFA). RESULTS: Phase 1 resulted in a preliminary questionnaire with four dimensions and 16 items. Sixteen experts completed two rounds of Delphi consultation, with high response rates (85% and 94.1%) and authority levels (Cr = 0.88 and 0.91). Consensus was strong (CV = 0.05 ~ 0.23; Kendall's W = 0.338 and 0.382, p < 0.001). Phase 2 validation showed a Cronbach's α of 0.967, with individual dimensions ranging from 0.911 to 0.950. I-CVI ranged from 0.813 to 1. The adjusted model indices met the fitting criteria. CONCLUSIONS: The developed questionnaire is a reliable and valid tool for assessing Chinese adults' intentions to reduce sedentary behavior. Grounded in TPB, it provides a theoretical foundation for future intervention studies aimed at addressing sedentary lifestyles.