somatotypes

Somatotype is a classification system for human body build and composition. It was proposed by psychologist William Sheldon in the 1940s and has since influenced discussions of physique in fitness and bodybuilding. The model identifies three broad categories: endomorph, mesomorph, and ectomorph. Endomorphs are described as having a higher proportion of body fat, a softer, rounded appearance, and wider hips. Mesomorphs are considered naturally muscular and well proportioned, with a more rectangular frame. Ectomorphs tend to be lean with a slender bone structure, narrow shoulders and hips, and limited body fat.

In practice, somatotypes are described along three scales, generating a three-number rating that reflects the degree to which someone exhibits each type. People usually display blends of the categories rather than fitting neatly into a single type, for example a meso-endomorph. The framework was historically linked with temperament and behavior, but current research offers little support for consistent associations between somatotype and personality or performance.

Modern use treats somatotype as a rough descriptive shorthand rather than a precise classification. It can inform general considerations in fitness planning and athletic training, but objective measures such as body fat percentage, waist-to-hip ratio, and muscle strength are preferred for assessment. The somatotype concept remains a historical influence on studies of physique, though its predictive value and scientific validity are regarded as limited and views on its applicability have evolved with advances in body composition science.