Last reviewed 06/2021

A human physical type (somatotype) tending toward linearity, as determined by the physique classification system developed by the American psychologist W.H. Sheldon. The somatotype was classified either as:

  • ectomorphic: characterized by long and thin muscles/limbs and low fat storage; usually referred to as slim
    • a person is classed as an ectomorph if ectomorphy predominates over endomorphy and mesomorphy in his body build
    • extreme ectomorph
      • has a thin face with high forehead and receding chin
      • narrow chest and abdomen
      • rather long, thin arms and legs; little body fat and little muscle
  • mesomorphic: characterized by large bones, solid torso, low fat levels, wide shoulders with a narrow waist
    • a person is classed as a mesomorph if mesomorphy predominates over endomorphy and ectomorphy in his body build
    • extreme mesomorph
      • has a square, massive head
      • broad, muscular chest and shoulders
      • heavily muscled arms and legs
      • minimal body fat
  • endomorphic: characterized by increased fat storage, a wide waist and a large bone structure
    • a person is classed as an endmorph if endomorphy predominates over ectomorphy and mesomorphy in his body build
    • extreme endomorph has a body as nearly globular as humanly possible
      • a round head, a large, round abdomen, large internal organs relative to his size
      • rather short arms and legs with fat upper arms and thighs, but slender wrists and ankles