In health-related group exercise, instructors play a vital role for the motivation and need satisfaction of participants. We present a new German language multidimensional questionnaire as a measure of instructor behavior in the context of exercise classes. We conducted two studies in order to develop and psychometrically test the new questionnaire (TRV-G). In study 1 (N = 228, age: mean [M] = 45.3 years, standard deviation [SD] = 15.2, 82% female) 36 items were developed and an exploratory factor analysis revealed a four-factor 20-item solution. Internal consistencies were good for the subscales individualized and specific feedback, care and individual consideration, and praise and encouragement, whereas the subscale clear and precise instruction showed a lower internal consistency. In study 2 (N = 204, age: M = 62.8 years, SD = 14.31, 60% female) confirmatory factor analysis revealed an acceptable fit. Further evidence was provided for the internal consistency and construct validity with the variables motivation (intrinsic, identified, introjected, external) and psychological need satisfaction (autonomy, competence, social relatedness). Motivation and need satisfaction were predicted significantly by the TRV-G subscales. The TRV-G was supported as a new measure of adult exercisers' perceptions of their instructor's behaviors within the context of group exercise classes which may also be used as a feedback instrument in instructor training.
