Autonomous motivation, exercise self-efficacy and outcome expectations as predictors of accelerometer-assessed moderate-to-vigorous physical activity in older adults: a cross-sectional study

Physical activity guidelines for older adults recommend a minimum of 150minutes of moderate-to-vigorous physical activity (MVPA)/week. The study examined well-established psychological exercise determinants (i.e. motivation, self-efficacy, outcome expectations) as potential predictors of accelerometer-assessed total MVPA. One hundred and twenty retired older adults were recruited from community centers in urban and rural areas of Rodopi, Greece. Participants completed questionnaires on psychosocial PA determinants (Behavioural Regulation for Exercise Scale, Barriers-to-exercise Efficacy Scale, Multidimensional Outcome Expectations for Exercise Scale). Multiple regression analysis tested in separate models if Autonomous Motivation (AM), Controlled Motivation (CM), Self-efficacy (SE) or Outcome Expectations (OE) predicted MVPA, controlling for age and sex. Participants spent on average 63.5min/day in MVPA and 91.2% met the MVPA guidelines. Only the AM model was significant. Age, sex and AM explained 19.1% of MVPA variance (R2=.44, F(3,116)=9.11, p<.001). AM significantly predicted MVPA (β=.20, p=.021), as did age (β=-.30, p<.001) and sex (β=-.16, p=.035). Study participants met the MVPA guidelines in vast majority and engaged in a high amount of MVPA daily. AM was a significant MVPA predictor, whereas CM, SE and OE were not. Further inspection of participant responses revealed that a) although participants mostly reported walking as the «exercise» they engaged in, some responded to the questionnaires having group-exercise in mind; b) in SE there was contrasting directionality in the association of individual scale items with MVPA, c) there was a ceiling effect in OE. MVPA seems to be embedded in housework that most participants engaged in, which is commonly considered light PA.

Kanavaki, A.M., Michalopoulou, M., Apostolidou, M., Gkrekidis, A., Kouli, E., Douda, H., Smillios, I., Gourgoulis, V., Syrakoulis, G., Aggelousis, N.