关键词: 儿童, 体型分类, 人体测量, 主成分分析, K-means聚类分析, 手肘法

Abstract: The purpose of this study is to explore the body shape differences among boys aged from 9 to 14 in Jiangsu province. Economic development and improved living conditions have led to significant changes in the body types of Chinese children, exhibiting notable regional and gender variations, as well as diversity. The existing children's clothing size standards are outdated and do not fully reflect these changes. Therefore, there is an urgent need to update the data and classification standards to better meet the demands of the children's clothing market. The primary objective of this study is to classify the body types of boys aged from 9 to 14 in Jiangsu province through scientific measurement methods and data analysis, further optimize the relevant children's clothing size standards, and provide guidance for the design and production of children's clothing.
In this study, 14 key body size measurements of boys aged from 9 to 14 in Jiangsu province were obtained by combining contact manual measurement and non-contact three-dimensional scanning technology. The collected data were processed and analyzed by using descriptive statistical analysis, correlation analysis, principal component analysis, and K-means clustering analysis. The results showed significant differences in body development among different age groups. Based on the results of descriptive statistical analysis, it was observed that as age increased, the growth rate of boys' height slowed down significantly, with boys aged from 9 to 11 growing faster than those aged from 12 to 14. Furthermore, correlation analysis results indicated that body-to-chest ratio, body-to-waist ratio, and body-to-hip ratio were more correlated with BMI than traditional indicators such as chest-to-waist difference and waist-to-hip difference, making them more suitable for classifying children's body types. Finally, through K-means clustering analysis, the body types of boys aged from 9 to 11 and 12 to 14 were divided into three categories: S (short and thin), M (medium), and L (tall and strong). Among boys aged from 9 to 11, the proportions were 31.10% (S), 38.28% (M), and 30.62% (L), while among boys aged from 12 to 14, the proportions were 19.19% (S), 62.63% (M), and 18.18% (L). These results indicate that as boys age, their body shapes tend to stabilize, with a higher proportion of medium body types.
Studying the classification of body types among children of different age groups is beneficial for revising and optimizing the children's clothing size standards in Jiangsu province, providing enterprises with reference for designing and producing clothing that better fits the actual body types of children in the region. To enhance the general applicability of the results, future research will include more regional samples, so as to further provide reference for the nationwide optimization of children's clothing size standards.

Key words: children, body shape classification, anthropometric measurements, principal component analysis, K-means cluster analysis, elbow method