Confirmation Regarding Physical Strength Based on Polynomial Regression Evaluation of Body Muscle Percentage for BMI in Korean Female Junior High School Students

Abstract

　This study investigated the physical strength based on a polynomial regression analysis of muscle mass percentage against BMI in South Korean junior high school students. The subjects were 148 schoolgirls of 14 years old. Physique (body height and weight) and body composition (BMI, fat mass, body fat percentage, and muscle mass, muscle mass percentage) were measured. The measurement items of physical strength were sit-up, sit-and-reach, push-up, and 20-meter shuttle run from the physical fitness test were adopted for the Korean students. In the polynomial regression analysis of muscle mass percentage for BMI, high reverse correlation (r=-0.77) was shown. In Slim type of BMI, the group of excessive development of muscle mass classified by standard polynomial regression evaluation chart was superior to other groups in 20-meter shuttle run. Significant difference was not shown in all items of physical strength in normal and fatty type of BMI. In other words, the level of qualitative accumulation of muscle was influence endurance ability in a slim type. However, it was suggest that the physical strength of the normal and fatty type not be influence by the level of qualitative accumulation of muscle. In the present study, BMI is newly located as an index of a muscle mass percentage, it was shown to be grasped physical strength handily by slim-fatty judgment by BMI.