2.2. Intervention Procedures
RA, Preschool
The present study comprised four intervention groups: the BM, RA, BG, and MA groups. Preschool children in the control group participated in unorganized PA, and the details of the interventions have been described elsewhere [The intervention program consisted of structured lessons with a duration of 30 min performed three times a week for 16 weeks. Kindergarten teachers participated in the study and performed the physical exercise interventions after receiving 2 h of training at a local kindergarten. The structure of each lesson consisted of a warm-up period of 5 min, followed by a core exercise period of 20 min and a cool-down activity of 5 min. The study was performed in the winter, and precautions were taken to ensure the safety of the preschool children, such as starting with low-intensity physical activity (e.g., wrist rotations and leg swings), gradually increasing the intensity (e.g., arm rotations and knee-up walk to forceful swinging of arms and on-site running), and then slowly decreasing the intensity. To ensure comparability across the different programs, the core exercise period followed a consistent intensity control principle, whereby every 10 min of sports activities should include at least 5 min of moderate-to-high-intensity physical activity and 2 min of vigorous-intensity physical activity. The interventions were designed as games to increase the children’s interest, with the main differences being in the core exercise content. The interventions were performed within the existing physical activity plans of the kindergartens to avoid additional physical activity for the preschool children in the intervention groups. The intensity of PA was estimated by teachers on the basis of the active behavior of the preschool children and was determined using the “Compendium of Physical Activity” developed by Ainsworth et al. [Preschool children in the control group participated in unorganized PA. The PA schedules were arranged by the kindergarten without the guidance of teachers, and the types and intensity of activities were determined by the preschool children.