Ectomeso

Ectomeso is an informal term used in fitness and bodybuilding circles to describe a person whose physique lies between the ectomorph and mesomorph end of William Sheldon’s somatotype spectrum. It is not an official category in the original somatotype theory and is not standardized in scientific literature; rather, it is a descriptive label that some athletes and coaches use to convey a mixed set of traits.

People described as ectomeso typically have a relatively slender or tall frame with low body fat, but show a propensity for muscle development in the upper body, such as the chest, shoulders, and arms, that is more pronounced than a pure ectomorph but not as bulky as a classic mesomorph. The criteria are imprecise and vary between observers, and individuals may shift between categories based on training and nutrition.

In practice, labeling someone as ectomeso is mainly for communicating dietary and training needs. Programs may emphasize hypertrophy and progressive overload, with attention to calories and protein, while also accommodating a lean physique. Critics note that somatotype classifications are simplified and may not accurately reflect genetics, metabolism, or athletic potential; many fitness professionals instead focus on individual measurements and response to training rather than fixed body-type labels. See also: somatotype; ectomorph; mesomorph.