Everyone fits neatly into one of three genetic body types, called a somatotype, and only a fool would adopt a training regimen that isn’t specifically slated for being either an endomorph, ectomorph or mesomorph.

Yeah, that’s bullshit. #sarcasm #notserious

Because while it can be interesting information to know your somatotype, and at the most basic level it can help identify potential weak and strong areas, it can also be useless; potentially even a hindrance to achieving your true genetic potential.

First, a wee bit o’ history.

The term somatotype was developed in the 1940s, not by a geneticist, but by a psychologist named William Sheldon. His creation of the three body types had nothing to do with weight loss or athletics, but to do with what he called “constitutional psychology.” This is now a neglected theory (A.K.A. Bullshit) that said a person’s body type would determine their temperament. Per this, well, let’s just call him a quack, Sheldon asserted:

  • The lean and long-limbed ectomorphs were cerebral, anxious, solitary and secretive.
  • The broad shouldered and muscular mesomorphs were risk-taking, courageous and assertive.
  • The roundish, short-limbed endomorphs were jolly, affectionate and complacent.

Like I said: bullshit. At least as far as ascribing personality goes. Nevertheless, it did gain traction in training circles because, very generally, these three body types did appear to have some applicability in terms of assessing physical strengths and weaknesses. But are the pros still applying it?

I spoke to some of the best trainers I know to get their take on somatotypes.

“I couldn’t remember which one is which,” said Nick Tumminello, who won the National Strength and Conditioning Association’s Personal Trainer of the Year Award for 2016.

“It’s not a mystery that genetics plays a role in training,” Tumminello said. “Genetic trainability comes in two forms: starting point and how you respond.” He explained that someone can have the appearance of being a skinny guy, as an example, but if he never trained then we don’t know his genetic destiny. He might be a “high responder.” If this skinny guy hits the iron his muscles might blow up. As another example, what Tumminello referred to as the true genetic freaks of the bodybuilding world are the ones who already looked muscular with no training, and were also high responders once they started training.

His advice? “You try different things and see where it gets you.”

“Body types and predispositions are far more complex than three categories,” Alex Viada a trainer and hybrid athlete. “The inherent complexity makes it sort of worthless to worry about. It’s difficult to know the limits of your fiber types, muscle attachment points, and so forth until you pushed yourself near your genetic limit, in which case I doubt you learn anything new by lumping yourself into a category.”

If I had lumped myself into a category I wouldn’t have accomplished what I have.

My upper body appears pretty mesomorph, but I have the wider hips and short legs of an endomorph. From the waist down I sure don’t look like a marathoner, and on the forced marches of junior high school gym classes they called 2-mile runs I was always at the back of the pack. I never thought I had it in me to be a runner.

But I did have decent trainability in this area. It didn’t happen fast—it was a real struggle to get good—but persistence paid off. My coach, who did VO2max testing on me when I was training to qualify for the Boston Marathon, said I had “a big engine.” I may not have the ultra-lean physique or long legs to be a champion marathoner, but that engine was able to push me to a Boston qualifying time only my second time attempting the 26.2 mile distance. A Boston qualifying time is something only 10% of people who run marathons achieve, and you never would have guessed I had it in me from looking at my body type. I had to push to find out what I could do.

What I just described coincides with Alex Viada’s argument against taking somatotyping too seriously.

“I think the biggest argument against somatotypes I want to convey is that you may not discover your body’s potential in any activity, or even its potential level of muscularity and leanness, until you’ve pushed it over years and years,” Viada told me.

Brad Schoenfeld, a bodybuilder and assistant professor of exercise science at Lehman College in New York, refers to somotypes as “a very gross overview of someone’s genetic potential.” He further explained that “a pure ectomorph will have trouble putting on appreciable muscle and a pure endomorph will have trouble getting lean. But most people are combo types so this doesn’t have much relevance.”

Schoenfeld also asserts that “the practical implications for programming are limited.” Something Nick Tumminello wholeheartedly agrees with.

“The principals of biomechanics and physiology don’t change based on genetics,” Tumminello said. “A biceps curl is a biceps curl. High load is high load. High reps are high reps. Going to failure is going to failure. None of those things change relative to your somatotype. What changes is the variance in your response to those stimuli.”

Tumminello did explain that certain body types will self-select for certain kinds of activity. The lean and long limbed person who naturally finds long-distance running to be easy will be more inclined to train to excel in that area. Vice-versa the person who is naturally strong may wish to find out just how strong they can get.

Rather than worry over somatotypes, Tumminello says, “Let’s give it a go and see how your respond.” He said that variables such as exercise selection, rep ranges, sets etc. are “goal specific, not body specific.” What’s more, he added that “I’m going to fit exercise movements to whatever you demonstrate competence in. It doesn’t have to do with somatotype, but how well you move your body.”

Overall, Tumminello sees worrying over somatotypes as “added confusion,” saying “If what you’re telling me doesn’t influence my programming, then you’ve wasted my time. You’ve given me Jeopardy information.

So unless you’re going on a TV quiz show and expect there to be a category on somatotypes, perhaps you shouldn’t concern yourself over it too much.


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James S. Fell, MBA, writes for the Los Angeles Times, Chicago Tribune, Women’s Health, Men’s Health, AskMen, the Guardian, TIME Magazine and many other fine publications. His first book was published by Random House Canada in 2014. He is currently working on his next book, which is about life-changing moments.