LAUSR

This study is a description of a short-term digital exercise intervention based on the theoretical framework self-determination theory and tested in a controlled trial. The sample consisted of 318 adult women (n = 279) and men (n = 40) aged 23–67 years (M = 46.7; SD = 9.4) participating in a digital step contest provided by their employer. All participants completed study baseline measures via validated web-based versions of the following instruments: Basic Psychological Needs in Exercise Scale, Behavioural Regulations in Exercise Questionnaire-2, and Leisure Time Exercise Questionnaire. These measures were repeated twice, 3 weeks (post-intervention) and 6 weeks (follow-up) after study baseline. The experimental group had access to the intervention platform for three weeks. Data were analysed by analyses of covariance and mediation variable analysis. Results showed the intervention to affect exercise level and intensity as well as basic psychological need satisfaction and behavioural regulations. Intervention effects on amotivation post-intervention were found to mediate total exercise behaviour at follow-up. Moderation analyses showed intervention effects on light exercise to be stronger for those participants engaging in moderate or high levels of light activities at study baseline. Also, the effect on identified regulation was stronger for those with low levels of identified regulation at study baseline. This study adds to the knowledge on exercise motivation based on short-term intervention effects on level and intensity of exercise and physical activity. The use of mediating and moderating analyses uncover processes underlying the main intervention effects. Findings are discussed in relation to self-determination theory and previous research.