Relationships Between Features of Somatic Development and Physical Fitness in 6-7 Year Old Lean and Obese Children

The aim of the study was to determine the relationships between indices of physical development and physical fitness in 6-7 year old children from the extreme ranges of fat content level. For 1114 boys and 1025 girls aged 6.6 the 95th percentile of skinfolds for obese children and the 5th percentile for lean children were a base for selection of 107 obese children (55 boys and 52 girls) and 138 slim ones (71 and 67) respectively. Body height, body mass, 5 skinfolds and body mass index (BMI) were measured. Physical fitness was assessed using four tests: sit and reach (flexibility), standing-broad jump (explosive strength), sit-ups (trunk strength and endurance) and step-test. A significant correlation between features of somatic development and physical fitness in children at the threshold of elementary school was only observed in lean boys and less numerously in obese girls. They explain no more than one-fifth of physical fitness conditions in investigated children. These observations should be taken into account in the assessment of physical fitness of children from extreme ranges of body fat content.