Fat-to-muscle ratio: exploring associations with motor competence and physical Fitness in 7-year-old children

Abstract

Featured Application: This study demonstrates that compartmental bioimpedance analysis, through the fat-to-muscle ratio, provides a simple and non-invasive method for identifying individuals at risk of exercise deficit disorder related to motor competence and physical fitness, as well as subsequent health risks. Consequently, it could be used to individualize physical exercise programs or physical education classes focusing on MC mastery and PF improvements based on muscle coordination and strength. Abstract: This study aimed (1) to explore the association between body composition [fat-tomuscle ratio (FMR), waist circumference (WC), and body mass index (BMI)] with motor competence (MC) and physical fitness (PFI) in 7-year-old children; (2) to ascertain whether FMR modifies the associations between MC and PF. A total of 164 children (7 yr) were included. Anthropometric (fat and muscle mass were calculated with TANITA), motor competence (CAMSA test), and physical fitness (1/2 mile run, handgrip strength, 10 × 5, standing long jump, and sit and reach tests) variables were collected. FMR, WC, and BMI correlated negatively with MC (all between r ≤ −0.333 and −0.183 and p < 0.05) and PFI (all between r ≤ −0.410 and −0.246 and p < 0.05) in all children. However, the associations were stronger for FMR. Only FMR was independently and negatively associated with MC and PFI in linear regression analyses, explaining 12.6% and 20.9% of its variance, respectively. Positive correlations between PFI and MC existed. Also, the association was not modified by FMR levels, since in both groups (above and below FMR median), the associations were maintained (p < 0.0001). However, the t-test showed that children with higher FMRs have lower levels of MC (p = 0.005) and PFI (p < 0.0001). FMR may be the best body composition parameter related to MC and PFI. Furthermore, the association between FMR does not modulate MC and PFI but children with higher FMRs show lower levels of MC and PFI