"läuft."--a school-based multi-component program to establish a physically active lifestyle in adolescence: study protocol for a cluster-randomized controlled trial.

Background: Physical activity during childhood and adolescence is associated with substantial health benefits and tracks into adulthood. Nevertheless, only 22.7% of German adolescents are sufficiently physically active. Thus, the promotion of an active lifestyle in youth is an essential issue of public health.This study will evaluate the implementation and efficacy of the "läuft." program to enhance physical activity in adolescence. "läuft." is a multicomponent school-based program developed on the basis of effective strategies for health interventions and behavioral change.

Methods/design: The "läuft." physical activity program targets four different levels. (a) Each student receives a pedometer and documents his/her steps over 12 weeks using an interactive user account on the "läuft." homepage. (b) For classes there will be different competitions, with achieving the most steps in selected weeks, the highest increases of steps and developing the most inventive ideas to promote physical activity in school. Besides, the intervention includes four educational lessons. (c) The headmasters and teaching staff of the participating schools will get information material with suggestions and encouragement to enhance physical activity in school. Participating teachers will be invited to an introductory seminar. (d) Parents will be provided with informational material about the program and will be invited to a parent-teacher conference about the benefits of being physically active and how they can support their children in engaging in a physically active lifestyle.To evaluate the efficacy of the "läuft." physical activity program, a two-arm cluster randomized controlled trial will be conducted in three waves: (1) baseline assessment, January/February 2014, (2) post assessment, June/July 2014 and (3) 12-month follow-up assessment, June/July 2015. Data collection will include physical and medical testing, self-administered questionnaires, group discussions and document analyses.

Discussion: "läuft." aims at fostering a physically active lifestyle in adolescence while a considerable decline of physical activity is present. Physical activity programs based in the school setting and following a multicomponent approach have been proven to be most successful. Furthermore, the use of pedometers is promising to enhance physical activity during the entire day and targets a wide range of adolescents regarding fitness and weight.

Trial Registration: Current Controlled Trials ISRCTN49482118.