Background: Despite of high motivation, compliance with home exercise is low in patients receiving physiotherapy. Predictions based on the strength model of self- control (Baumeister et al., 2007) were tested by investigating whether high self-control demands at work lead to difficulties to begin with home exercise and to low actual exercise behavior (ego-depletion). It was also tested whether relaxation can counteract the effects of ego-depletion. Methods: 40 patients who should do home exercise every after work day took part in a RCT with 2 groups over a period of 5 working days. One group conducted a standardized relaxation (15 minutes) before starting the exercises; the other group conducted the exercises straight after work. Self-control demands at work, the perceived difficulty and actual exercise behavior were assessed by a daily survey. Findings: ANOVAs revealed no significant group effect. Self-control demands at work were positively associated with perceived difficulty (r= .50; p < .01) and negatively associated with actual exercise behavior (r= -.25; p = .17). Perceived difficulty was also negatively associated with actual exercise behavior (r= -.55; p < .001). Discussion: Results suggest that high self-control demands at work lead to a state of ego-depletion which consequently reduces compliance with home exercise. The missing group effect can be due to methodological issues.
