Validity and reliability of the motivation for physical activity (RM4-FM) questionnaire.

There is a lack of validated instruments measuring motivation for physical activity (RM4-FM) in the Finnish language. The study examined the translated RM4-FM instrument's psychometric properties in a sample of healthy, older Finnish adults. RM4-FM was translated and linguistically validated adhering to published guidelines. 65-75-year olds (n=102), completed the RM4-FM, the physical activity acceptance questionnaire (PAAQ) and sociodemographic characteristics questionnaires electronically. The RM4-FM was readministered one month after the initial assessment. RM4-FM translated well into Finnish. Motivation dimension scores were skewed towards high internal and low external motivation. A floor effect was confirmed in the dimension and a ceiling effect was confirmed in the dimension. Confirmatory factor analysis indicated inadequacy of the four-dimension model. Separate assessment of each of the four motivation dimensions with Exploratory factor analysis showed unidimensionality for all dimensions. Exploratory factor analysis provided a best-fit model of three factors (influence of other people, intention of well-being and emotional aspect of motivation). Readministration of the instruments showed good test-retest reliability in all motivation dimensions. Female gender, higher education, and higher PAAQ score were associated with higher internal motivation and lower external motivation scores. The Finnish version of the RM4-FM instrument provides valid and reliable scores in assessing motivation for physical activity in healthy, older Finnish adults. The score distributions suggested shortages in the scale when evaluating internal motivation. The three-factor model of the RM4-FM provided more favorable structural validity compared to the original version.