Abstract:
This dissertation thesis aims to contribute to the research needed in the field of health-promotion through physical activity in young people in the school setting and consists of mainly three consecutive steps targeting to provide theory-based empirical findings on a high evidence level. In the first step, it was revealed that young people’s health and fitness status decreased in the last years (e.g., Kurth & Schaffrath Rosario, 2007; Bös, 2003). Nevertheless, existing meta-analyses conclude that a promising picture of the positive health effects of fitness and physical activity on several health aspects in young people exist (e.g., Janssen & LeBlanc, 2010; Ortega et al., 2008). Additionally, the importance of the school setting to encourage a healthy lifestyle was discussed from the perspective of sport psychology, sport pedagogy, and training science (Biddle & Nigg, 2000; Frey & Hildenbrandt, 1995; Kurz, 2008; Steinmann, 2004).
In the second step of this dissertation thesis, a systematic review on the effects of school-based physical activity intervention studies on young people’s psychological determinants of physical activity, the behaviour physical activity itself, and health and fitness variables was carried out (Demetriou & Höner, 2012). The findings revealed that a large amount of studies positively influenced students’ knowledge (87.5%), motor performance levels (69.7%), and physical activity levels (56.8%). A smaller amount of studies had a positive impact on students’ attitudes (43.8%), self-concept (30%), and BMI levels (28%). Additionally, a more detailed literature search was carried out to find further studies carried out in German language countries, which were not detected with the strict inclusion criteria of the main systematic review. These studies strengthened the positive picture of the results found previously.
In the third step of the research project, the design of HealthyPEP was described, which was developed based on the sports science considerations and the findings of the systematic review. The lessons consisted of age-appropriate practical training, theoretical elements, and some additional components such as PE homework. By using specific behaviour change techniques (Michie et al., 2009), in was targeted to provide students the opportunity to experience the effects of regular training and the association between health and physical activity. The evaluation of HealthyPEP was carried out with a total study sample of 18 sixth-grade high school classes (N=516) using a quasi-experimental design. The IG classes carried out HealthyPEP and the CG continued the regular PE lessons. A comprehensive evaluation was carried out using process measures to examine the degree to which HealthyPEP was successfully implemented and outcome measures to analyse the intervention effects on: a) the psychological determinants of physical activity, b) the behaviour of physical activity, and c) the health and fitness level. Finally, students’ cooperation with each other was measured to examine possible side effects of HealthyPEP (Mittag, 2006). The process measures revealed a positive picture concerning the implementation of HealthyPEP and its evaluation by the participating teachers and students. The results on the outcome variables revealed that HealthyPEP showed intervention effects on BMI and girls’ motor performance but did not positively influence students’ HRQOL, psychological determinants or their physical activity behaviour. Several methodological problems concerning the study design and the measurement instruments used need to be taken into account when interpreting these findings. This leads to the conclusion that positive effects could only be achieved through the direct influence of HealthyPEP that was more intense and energy consuming compared to the regular PE lessons.