The purpose of this study is to analyze the effect on %fat and growth of the physique by the child’s participation and its degrees in life sports. Life sports participation and the jump-rope level can be classified into 3 groups, that is, a positive, a normal, and a negative one through the observation for the participant’ the jump-rope and interviews with them after 3 weeks exercise. Jump-rope scale is measured by the items based on Son’s etc.(2000)’scale. 775 subjects, from 8 years old to 12 years old children are selected. χ² test, 3-way ANOVA(gender, age, participative type), and regression are used to solve problems of this study. From the investigation, the conclusions are as follows; 1. There are no significant differences by gender, age and participative type in frequencies of groups. 2. There is a significant difference in height and sitting height that is increased with age. But, there are significant differences in weight, chest girth and BMI by gender, age and participative type group ; boy’s are higher than girl’s, those are increased with age, and positive group’s are less than negative group’s. And there are significant differences by main effects of gender and participative group in %fat ; boy’s have about twice as much as girl’s and positive group’s are less than negative group’s. In addition to that, in %fat, there are significant differences by interaction effect of gender and age ; boy’s are decreased with age but girl’s increased. 3. There is a different effect between positive participants of gender on growth of height ; %fat of boy has negative effect, but girl’s positive. 4. There are different effect and factors on %fat in each group ; the positive participative group of boy has BMK(+), weight(-), boy’s negative group has BMK(+), weight(-), chest girth(+), sitting height(+), and girl’s both groups have BMI(+).