The Changes Of Fat Content Of Late Puberty Students And Comparative Study Of Evaluation Methods Of Body Fat Percentage

In this study, by the results of dual energy X-ray absorptiometry(DEXA) as the standard, analyze the results of skinfold thickness method, bioelectrical impedance (BIA) and body mass index (BMI). Research and discussion the body fat distribution characteristics and law of high school students of different body type and sex, analyze the difference of different measurement results calculating the body fat rate for high school students and the relevance of the measurements, thus provide methodological basis for finding the measurements and speculating formulas which are suitable for high school students used, simple, effective and accurate in body fat content and body fat percentage. Select 119 high school students of bone age of 15 to 18-year-old as research subjects in school (60 boys,59 girls), and filtered with BMI. Using BIA, DEXA, skin fold thickness method, circumference method to measure the same subjects of body composition indicators. Data processing is the conventional statistical methods.Conclusions:1. With the increasing in human obesity, body fat ratio of body parts, waist circumference, hip circumference, waist to hip ratio and skinfold thickness of body regions etc. indexes of male and female students among different body type increase. The abdominal region is where the body fat mass increases the most. The body fat ratio and skinfold thickness of female students are more than males students'. With the increase in human obesity, males are more likely to accumulate fat in trunk, whereas females'fat distributes evenly in trunk and limbs.2. By the body fat percentage results of dual energy X-ray absorptiometry(DEXA) as the standard, the measurements of bioelectrical impedance analysis, and the estimation results of the original formula for skinfold thickness compare with it.It is observed that the error of BIA results for male students is smaller, but larger for female students. The error of the estimation results of the original formula for skinfold thickness for late puberty students is largest. Be cautious when use this two methods.3. In this study, established the speculating body fat percentage formula of bone age for 15-18 years old (male 16-18 years old, female 15-17 years old) students with simple morphological indexes and skinfold thickness indexes has good reliability and validity. They are as follows:Male:Body fat percentage=-50.875+0.572×hip circumference+0.777×BMIBody fat percentage=-1.421+0.812X calf skinfold thickness+0.357×scapular skinfold thickness+0.305×abdominal skinfold thicknessFemale:Body fat percentage=-21.036+1.036×BMI+0.343×hip circumferenceBody fat percentage=9.956+0.671×bicepsskinfold thickness+0.451×abdominal skinfold thickness+0.407×scapular skinfold thickness...