Association between body mass index, muscle-to-fat ratio, and handgrip strength-to-BMI ratio with physical fitness in children from North Macedonia.

Background: this cross-sectional study, conducted on a convenience sample of 2197 Macedonian primary school children, aimed to examine how certain anthropometric indices (body mass index (BMI), muscle-fat ratio (MFR), hand grip strength-BMI ratio) are related to the physical fitness of individuals.

Methods: the sample was split into two groups based on gender: 1096 boys and 1101 girls (average age 8.1 ± 1.3 years). Data on anthropometric measurements (BMI, MFR) were taken and the physical fitness was measured with the following tests: sit and reach, handgrip strength, standing long jump, sit-ups 30 sec., shuttle run 4 x 10 m, and 20 meters shuttle-run test (20-mSRT).

Results: the findings from the study indicate that children with normal weight exhibit superior levels of cardiorespiratory, muscular, and motor fitness in comparison to those who are categorized as obese, irrespective of gender. Both muscle‑to‑fat ratio (MFR), and grip strength-to-BMI ratio showed correlation with most fitness tests. Grip strength-to-BMI ratio showed a positive correlation with the results of the handgrip test in boys and girls.

Conclusion: in this population, BMI, MFR, and handgrip strength-to-BMI ratio can serve as indicators of health and physical fitness.