Measuring functional limitations in rising and sitting down: Development of a questionnaire

Objective: Develop and test a self-administered questionnaire that measures perceived and actual functional limitations in rising and sitting down. Setting: Private practices for physical therapy and outpatient clinics of hospitals and rehabilitation centers. Patients: 345 outpatients (43% male, aged 14 to 92 years) with different grades of functional limitations and different types of lower extremity orthopedic or rheumatologic disorders. Methods: The Questionnaire Rising and Sitting Down (QR and S) was developed on the basis of a literature review and careful operationalization of functional limitations. Five dimensions concerning different objects (high chair, low chair, toilet, bed, and car) and one global dimension were postulated to be contained in the instrument. Mokken scale analysis was used to test the postulated dimensions (scalability coefficient H). Furthermore, robustness with respect to patient characteristics was determined, as well as intratest reliability (reliability coefficient Rho), test-retest reliability (intraclass correlation coefficient [ICC]), content validity (coverage of operationalized aspects), and construct validity (testing of seven hypotheses). Results: Mokken scale analysis confirmed the existence of 5 object dimensions (H = .53-.59). However, two global dimensions were found (H = .50-.54). The resulting hierarchical scales, consisting of subsets of the 32 final QR and S items, are robust and measure functional limitations in a reliable (Rho .77-.91; ICC .72-.90) and valid (3 out of 4 aspects covered, 2 hypotheses rejected for 3 out of 7 scales) manner. Conclusion: The QR and S is a reliable and valid self-administered questionnaire. It consists of hierarchical scales and measures perceived and actual functional limitations in rising and sitting down.