In the field of physical activity recommendation, we have to deal with many confounding variables that lead to high result uncertainty. Assuming that users' competence is an essential factor for reduction of the problem of inaccurate recommendations, we present and evaluate an approach on how to integrate users in the recommendation process. We investigate if and how interface element design can contribute to understanding, reflection and modification of the recommendation result. In the work

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... scribed here, we use interface elements that allow for planning of physical activity goal striving. Results show that such interface elements can principally empower users, support recommendation reflection and stimulate user interaction with the recommendation.