Study On The Variation Of Body Composition And Skin-fold Thickness Of 7 To 15–Years Old Primary And Middle School Students In Guangdong Province

Purpose : This study aims at making a comprehensive test analysis for the 7 to15-year-old primary and secondary school students' body composition,skin fold thickness and body circumference.Explore the changes of body composition,skin fold thickness and circumference,providing guidance for the growth and development of primary and middle school students in puberty,providing theoretical basis for scientific movement.Method:This study chose 7 to 15 years old in Guangdong Province as the research subjects.There are 1399 individuals in total,in including 591 males and 748 females.Analysis of body fat percentage,fat mass,fat weight and muscle mass by bioelectrical impedance method.The thickness of the upper arm skin fold,the thickness of the scapular skin,the thickness of the lumbar skin-fold,the thickness of the abdominal skin-fold,the thickness of the skin of the thigh and the skin-fold thickness of the lower leg were measured by the pleated calipers.Using the tape to measure the circumference,were measured chest circumference,waist circumference,hip and thigh circumference parts.The measured data were analyzed by mathematical analysis.The body composition,skin-fold thickness and circumference were the same in different age and same sex.The changes of body thickness and circumference were analyzed by one-way ANOVA.The same age of different sex and puberty at the same time in different sex were used independent sample T test for analysis.Body composition and skin-fold thickness for person correlation analysis.Results:1.With the growth of age,7?15 years old male and female body composition of each index changes.In the process of growth and development,female body fat percentage and fat mass were higher than males,but the fat free mass and muscle mass of males than females.2.The skin-fold thickness of boys increased at 7 to 9 years old,between the ages of 9to 10,there was a decrease in skin-fold thickness,and the 11 to 15 years old showed a slow growth trend.Females skin-fold thickness of 7 to 11 years old curve was growing,11 to 15 years old was wave-like changes.Male and female parts of the circumference increases with age,but the growth and development of males is slower than females.3.According to the different stages of puberty grouping,girls enter the early age of puberty about 9 years old,males around 11 years old.In different periods of puberty,males' fat free mass and muscle mass were higher than that of females.The percentage of fat in females is higher than males,and the fat mass is higher than females before the late stages of puberty,however,to the late development of females in fat mass was higher than males.In different periods of puberty,the skin-fold thickness and circumference of males and females increased with the development of youth,in the middle and late stages of puberty,the otherness was small.In the same period of puberty,males' skin-fold thickness and circumference are relatively higher than females.4.The correlation coefficient between the skin-fold thickness of each part of the body and the percentage of fat in the body composition was highly correlated between 0.71 and 0.82,and P < 0.05 was statistically significant.Conclusion:1.In the process of puberty,the percentage of fat and fat in females is higher than males,which indicates that the probability of obesity is higher than that of males.2.Skin-fold thickness and circumference of the comprehensive changes can be concluded that the males of the waist and abdomen is more prone to accumulation of fat,females buttocks and thighs more likely to accumulate fat.On the other hand,males prone to apple-type obesity,females were pear-type obesity.3.From the results of the puberty development can be drawn.females into the puberty period earlier than males about 2 years,while male and female physical form of the main differences in the late stages of youth development.4.The correlation coefficient between skin-fold thickness and fat percentage was higher.Therefore,children and adolescents in the growth and development process using a simple skin-fold thickness measurement can calculate the body fat content of the curve.