Abstract
Introduction As physical inactivity represents a major societal problem, it is essential to understand which factors favor health-enhancing physical activity (PA). One component that underlies motivational processes, but also influences behavior directly, is outcome expectations. As there are hardly any instruments available to assess PA-related expectations in younger adults, the aim of this work was to develop a questionnaire to measure such expectations. Methods A questionnaire was developed over three studies: In the first study, a raw questionnaire with 100 items derived from literature analysis was generated, then reduced, and its factor structure was determined. In the second study, internal consistencies, goodness of fit, and construct validity were examined. In the third study, the test-retest reliability of the questionnaire was analyzed. Results The process resulted in a 15-item questionnaire with a five-factor structure (‘psychological’, ‘appearance-related’, ‘performance-related’, ‘social’, and ‘health-related’ expectations) and satisfactory internal consistency. Goodness of fit, which was determined in study 2, yielded good model fit (five-factorial model); furthermore, acceptable correlation coefficients ( r ≥ 0.45) for convergent validity were found. Intraclass correlation coefficients for test-retest reliability examined in study 3 yielded values between 0.63 and 0.87. Discussion The resulting PA-EXPECT-YA is a brief and reliable 15 item-instrument that enables the economical measurement of PA-related expectations in young adults. Overall, the PA-EXPECT-YA demonstrated good psychometric properties; however, further research on the ‘performance-related expectations’ factor is recommended. Refining the respective items could enhance internal consistency and test-retest reliability values of the factor.