2009 Volume 55 Issue 2 Pages 145-154
This study compared body composition and physical fitness, based on a polynomial regression analysis of body fat percentage against BMI for the relational between body composition and physical fitness, in Japanese and South Korean junior high school students. The subjects were 183 Japanese students in the second year of junior high school, and 231 South Korean students in the first year of junior high school. Measurements of physique (body height and weight) and body composition (BMI, fat mass, body fat percentage, and muscle mass) were carried out in the Japanese and South Korean students. In tests of physical strength, items from the new physical fitness test were adopted for Japanese junior high school students, and grip strength, sit-ups, sit-and-reach, side steps, endurance running, 50-meter dash, standing long jump, and handball throw were measured. For the Korean students, sit-ups, sit-and-reach, push-ups, and 20-meter shuttle run were measured. In an analysis of physical fitness among obese, average, and thin body types determined by BMI, more of the Korean students were classified as the obese type. It was also found that in both Japanese and Korean junior high school students physical strength was inferior in the obese type. The level of qualitative accumulation of fat was determined from polynomial regression analysis for BMI, and classified in three patterns: excessive development of fat, average, and underdevelopment of fat. A comparison was made between the Japanese and Korean students in the distribution of these classifications, and it was found that there were more students with excessive development of fat among the Korean students. From inspection of the physical fitness of students in each of these classifications, it is inferred that body fat has a negative influence on physical strength.
