Fundamental Movement Skills And Bmi Mediate The Relationship Between Physical Activity And Fitness In Children

Active children tend to be more physically fit, while those with higher body mass index (BMI) have lower physical fitness (PF) levels. Further, more proficient children in their fundamental movement skills (FMS) are expected to be engaged in more moderate-to-high intensity physical activity (MVPA) and be physically fitter. PURPOSE: To examine the relationship between MVPA and PF, and the mediating roles of BMI and FMS in children. METHODS: From the RUSH research project, 1166 Portuguese primary school children from both sexes, aged 6-10 y, were sampled. MVPA was obtained via accelerometry (Actigraph wGT3X-BT) for 7 consecutive days. BMI was computed from height and weight, and their z-values (BMIz) were computed using World Health Organization references. PF was assessed with the standing long jump, handgrip, shuttle run, 50-yard dash, and the pacer. FMS, namely object control tasks (stationary dribble, kick, catch, overhand throw, and underhand roll), were reliably assessed with the Meu Educativo digital platform. Individual sex-specific z-scores, adjusted for age, were computed for each PF test and then summed to obtain an overall PF measure. The mediation analysis was done in the PROCESS software v.4.2. RESULTS: The effect of MVPA on BMIz = -0.21 ± 0.52 (R2 = 1.4%), and on FMSz = 0.29 ± 0.03 (R2 = 8.4%). Further, 22% of the total variation in PFz was accounted for by both mediators and MVPA. However, approximately one-half of the effect of MVPA on PF (50.5%) is attributable to the mediators BMI and FMS. In sum, the direct effect of MVPA on PFz = 0.12 ± 0.03; and the indirect effect through BMIz = 0.02 ± 0.005, and FMSz = 0.11 ± 0.01; the total indirect effects = 0.13 ± 0.02. CONCLUSIONS: There is significant evidence that BMI and FMS mediate the relationship between MVPA and PF in schoolchildren. Thus, it is of utmost importance to consider these children’s characteristics when designing physical education classes and/or sports practices to improve their physical fitness. La Caixa Foundation (SR21-00229)