Maturity Status and Fat-Free Masses as Determinants of Physical Fitness Among Macedonian Schoolchildren aged 6 to 14

Abstract

Study purpose. The research goal was to establish if the fat-free mass, chronological age and maturity status are determinants of physical fitness, and to analyze the development changes of fat-free mass and physical fitness in concordance with chronological age and maturity status in schoolchildren aged 6 to 14. Materials and methods. The research was conducted on a sample of 9106 students aged 6 to 14 years. In order to reach the research goals, the following variables were measured: height, weight, sitting height, fat mass, fat-free mass and various components of the physical fitness (lower limbs explosive strength, handgrip strength, abdominal muscle repetitive strength, speed and agility). The values of body mass and biological maturation indexes (APHV) were obtained by using formulas. Results. The boys’ age at peak height velocity was estimated at 13.00±0.82, and the girls’ one at 11.57±0.68. The relationships between chronological age and age at peak height velocity with fat-free mass was r=0.82 to 0.94 in the boys and r=0.83 to 0.92 in the girls. The relationships between fat-free mass and physical fitness tests in the boys were: standing long jump (r=0.55), 30 sec sit-ups (r=0.37), handgrip strength (r=0.75) and shuttle run 4 х 10 meters (r=-0.40); and in the girls – standing long jump (r= 0.45), 30 sec sit-ups (r= 0.36), handgrip strength (r= 0.74) and shuttle run 4 х 10 meters (r= -0.43). The differences in fat-free mass and physical fitness tests were more prominent when the comparison was done with relation to the biological maturation (APHV) and chronologic age. Conclusions. On the basis of the obtained results, it can be concluded that maturity status and fat-free mass determinate the physical fitness performances in the schoolchildren of both genders. Also, the age at peak height velocity should be used in Physical Education as a tool of monitoring, ranging and classification of physical performances in children and adolescents.