Physical activity and sport participation often decline during adolescence.
To investigate if physical exercise during 6 months could lead to a positive behavior of physical activity, improve physical fitness and self-related health in physically inactive female high school students.
A prospective cluster-randomized controlled intervention study included 104 physically inactive female high school students, 60 in an intervention group and 44 controls. At baseline there were no group differences regarding self-related health. The intervention group exercised at least once per week. A questionnaire and physical fitness tests were used for evaluation, at baseline and 6 months later.
The intervention group improved their self-related health compared with the controls (P = .012). When divided into a regular (n = 27) and an irregular training group (n = 33) the regular training group improved their self-related health compared with the controls, while the irregular training group did not differ from the other groups. Maximal oxygen consumption was improved in the intervention group compared with the controls (P < .001). No group differences were found in muscle strength and endurance.
Physical exercise at least once per week during 6 months improved physical fitness (maximal oxygen consumption) and self-related health in physically inactive female high school students.