This study examined the relationship between basic psychological need fulfillment (BPNF) and school happiness in relation to the intensity of physical activity exhibited by adolescents during physical education (PE) classes and their obesity levels. We measured BPNF and school happiness using a questionnaire administered to 600 junior high school students. After exclusion, 532 questionnaires were analyzed. A 3D accelerometer (GT3X model) from Actigraph and the body mass index were used to measure physical activity intensity and obesity, respectively. The findings of this study indicate that BPNF and school happiness were significantly associated with physical activity intensity. Specifically, students who engaged in high-intensity physical activity exhibited higher levels of BPNF and school happiness. Additionally, BPNF and school happiness were not significantly related to obesity, whereas a significant relationship was observed between BPNF, school happiness, and the interaction between physical activity intensity and obesity level. This finding implies that adolescents with higher physical activity intensity and lower obesity reported higher levels of BPNF and school happiness. These findings suggest that physical activity intensity during PE classes significantly influences emotional development. Therefore, incorporating moderate-to-vigorous physical activity into PE may serve as a strategy for promoting emotional development in adolescents.
Keywords: basic psychological need fulfillment; intensity of physical activity; moderate-to-vigorous physical activity; obesity level; school happiness.