The purpose of this research is to understand the physiological characteristics of muscular men between the ages of 20 and 34 years who are distinct from the general population due to their muscular development, and to categorize them according to upper body somatotypes. This research was conducted in order to provide basic data necessary for developing clothing products for muscular men. The research method and results were as follows: the "Sheldon's" and "Heath-Carter" somatotype classification methods were carried out at sports centers, the Athletic College, and military bases in Seoul and Gyeonggi province. Excluding the 32 subjects that did not have a balanced mesomorph, ectomorphic mesomorph or mesomorph-ectomorph, research on the remaining 168 subjects was used in the data analysis. 2. We used the following factor analysis: factor 1 for torso size; factor 2 for upper-arm, armpit, and chest breath size; and 3. The upper body was categorized into four (4) types, and their individual characteristics were as follows: Type 1 had the most developed arms, shoulders, chest muscles, and the shortest height. These subjects had an average of 191 somatotype points and could be classified as a balanced mesomorph. The heights and the lengths of Type 2 were short. They had slim physical structures, averaged 182 somatype points, and could be classified as an ectomorphic mesomorph. somatotype points and were classified as a balanced mesomorph. The heights and the lengths of Type 4 were long. They had slim physical structures, averaged 164 somatotype points, and were classified as a balanced mesomorph-ectomorph. 4. After carrying out a discriminant analysis to validate the categories of muscular men's upper bodies, we concluded that our model had an accuracy rating of 98.1%.