Purpose: The aim of the study was to examine if brisk walking is an effective physical activity for promoting adolescents' mental health. Design and methods: This quasi-experimental study employs a one-group repeated-measure design. Sixty-four volunteer students in 10th to 12th grade were recruited from a high school in central Taiwan, and they participated in a brisk-walking program for 12 weeks. Psychological functioning was measured by self-concept, anxiety, and depression scores (Beck Youth Inventories-Second Edition; BYI-II). Measurements were conducted at baseline, and 4,10 and 16 weeks after baseline. The effects of the program were analyzed using generalized estimating equations (GEE). Results: Significant decreases were seen in anxiety and depression and an increase in positive self-concept. The effect of physical activity on anxiety was clear and could be observed after 6 weeks of the brisk-walking program. Brisk walking for 30-, 60-, and 90-min sessions was examined, with the 60-min session proving more effective than shorter or longer sessions. Conclusions: The results suggest that a 12-week brisk-walking program may be effective both at decreasing depression and anxiety and at improving self-concept. The study also showed that anxiety could be considered a risk factor for depression. Further, self-concept was found to be a mediator acting on the psychosocial mechanism of physical activity promoting mental health in adolescents. Practice implications: While most physical activity programs in past studies combined different activities, the present study demonstrated that brisk walking alone is a simple, effective exercise regime that promotes adolescents' mental health. (c) 2021 Published by Elsevier Inc.
