Moderators of the effect of high-intensity and moderate-intensity games in school children on cardiorespiratory fitness and body composition

This study examined the moderators of sex, maturity sexual stage, and age in the intervention of high intensity and moderate-intensity exercises on changes in cardiorespiratory fitness (CRF) and body composition. Forty-eight children (aged 9,48±0.5 years), 32 girls and 16 boys, were selected randomly to perform high-intensity intermittent games (HIIG) and moderate-intensity games (MIG). The intervention is applied in the physical education (PE) class. Twenty meters shuttle run test was used to estimate CRF, and body composition was measured by body fat percentage (BF%), the skinfolds sum, body mass index (BMI) z-score, and waist circumference (WC). Sex, sexual maturity stage, and age did not moderate the result on changes in Delta difference (Δ) in CRF. Furthermore, no moderation was observed in the interaction between groups of CRF intervention. A significant moderation of the interaction between groups of the intervention was observed on ΔWC. Hence, they differ in their effectiveness according to sexual maturity stage in connection to ΔWC. In sexual maturity stage and age, a quasi-significant value of moderation of the interaction between groups of intervention respect ΔBMI z-score was also observed. HIIG can be incorporated into PE classes regardless of sex, sexual maturity stage, and age ΔCRF. MIG group may have a better effect on body composition on students with sexual maturity stage Tanner 2 and 9-year-old children. High-intensity intermittent activities improve CRF and can be incorporated with no restriction of the moderators studied in PE class. Therefore, it turns into an alternative for PE class.