In the 1940s, William H. Sheldon introduced his theory of Somatypes in two major works, The Varieties of Human Physique (1940) and The Varieties of Human Temperament: A Psychology of constitutional Differences (1941). His theory proposed three basic body types and associated them with a sets of personality characteristics. Today, Sheldon’s description of three body types has become central to much of the literature in weight loss, exercise and body-building.
This system defines three distinct categories of human bodies: the endomorph, characterized by a preponderance of bodyfat; the mesomorph, marked by a well-developed musculature; and the ectomorph, distinguished by a lack of either much fat or muscle tissue. These differences were, of course, not exact in every body, and individuals can rate themselves for the three dimensions of body type they possess.
Ectomorphs are generally small-framed and thin. Their shoulders and hips are generally narrow. They have trouble gaining weight and building muscle. Ectomorphs should do enough cardio exercise to work their heart and lungs but not so much if they are concerned about building muscle and maintaining weight. Weight workouts should be on the heavier side if the goal is to build muscle. Weight training the upper body is helpful to keep proportions more even. Generally, lighter weights and more reps do the trick.
Mesomorphs tend to be of normal weight, neither fat nor skinny. They tend to pack on muscle easily and can lose weight easily up to a certain point. It is hard for them to become “skinny.” Generally, their shoulders are wider than their hips. Mesomorphs should do longer-duration, higher-intensity cardio work if the goal is to lose weight. Building muscle is easy, but if the goal is not to gain size then moderately heavier weights and higher reps will be the way to go during weight-training sessions.
Endomorphs tend to have a soft skinned body that is pear-shaped, meaning their hips are usually wider than their shoulders. They gain weight easily and tend to be curvier than the other body types, as well as having trouble losing weight. Tend to have an over-developed digestive system.
Most of us aren’t purely one body type or another; we are a combination of at least two.
Whatever your body composition, it should never diminish your ability to enjoy your running.