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Bodybuilding and genetics

Bodybuilding and genetics


Every human being is "built" on the same model. However, while we all logically have a body with two arms, two legs, a head, etc., we are not identical. What is it that makes us so unique and sets us apart from the rest? Genes, of course!

Genetics: definition

Genes are the code that make up our DNA, defining who we are and what we can't change. They are hereditary, taking on some of the physical (and perhaps physiological) characteristics of both our parents. Genetics thus refers to the scientific field of genes and heredity.

Genetics and our relationship to performance

A subject that regularly crops up in training room conversations is the place of genetics in performance, and more specifically in the ability to build muscle. In other words, are we all equal when it comes to muscle gain, fat loss or strength?

Well, no! Unfortunately, some people are better off than others, thanks to their genes.

the influence of genetics on sporting ability


A number of factors determine our ability to gain muscle more or less easily. First of all, there's our morphotype. There are three morphotypes, and depending on which one we belong to, our physical potential will differ.

  • endomorphs will have a strong tendency to put on weight, but mainly in the form of body fat, as their metabolism is relatively slow.
  • the ectomorph will find it very difficult to put on weight, despite eating large quantities of food. Its metabolism is very fast, and it gains muscle mass only very slowly, if at all.
  • Mesomorphs are by far the easiest to build muscle with. They have a relatively fast metabolism, which makes muscle gain relatively easy and fat gain relatively limited.

These morphotypes were first introduced into medical literature by Professor William Sheldon in the 1940s. Trained as a psychologist, he associated these physical characteristics with psychological traits.

dNA and strength

the other aspect to be taken into account in the ability to build muscle is "muscle composition". Muscles are made up of two types of fibers, genetically distributed throughout the body:

  • White fibers, designed for fast, powerful contractions. These have a high capacity for hypertrophy (i.e. the ability to grow).
  • Red fibers, which are more enduring, but have a much more limited capacity for hypertrophy.

So, depending on your genetic make-up, you may have a natural predisposition for bodybuilding (or any other strength sport) or, on the contrary, for an endurance discipline. It is estimated that the distribution of fibers can be modified by up to 50% (the remaining 50% are immutable). As a result, with intensive training, you can have a muscular system made up largely of white fibers.

Accessory characteristics

In addition to the composition of your muscles, there are anatomical characteristics: are they long or short? This is linked to the insertions and length of your tendons. Short muscles, with long insertions, are more susceptible to tendon injuries and require extra care when stretching.

The length of your segments will also play its part in your ability to develop your physique. Long segments make certain movements more difficult to perform, as the impact of the load on the joint during training will be greater.

Genetic inheritance: determinism

As you can see, genetics lay the foundations for your physique, and unfortunately you can't change them. But that's no reason not to embark on the quest for an athletic physique.

By acting on your diet and taking into account your metabolic type, it's possible to modify your fat/muscle mass ratio and consequently your appearance.

You won't be able to change your bone structure, but by developing certain muscle areas more than others, you can compensate. For example, narrow clavicles can be compensated for by developing the external deltoids, giving the impression of width.

A taller person will be at a slight disadvantage compared to a shorter one, because to achieve the same visual effect, he or she will need to build up more muscle. In fact, a kilo of muscle spread over a person of 1m80 will be less visible than on a person of 1m70.


To sum up, genetics plays a role for any athlete in any sport, as it lays down certain foundations that you'll have to work with.

However, there are many examples of athletes who didn't have everything going for them, but who, through hard work and determination, were able to adapt their training and nutrition to their physiological characteristics and build a massive physique. Dorian Yates and Phil Heath are among them.

Your genetic potential may slow down your rate of progress compared to a naturally more "gifted" person, but if you put all your assets on your side, it shouldn't prevent you from reaching your goal.

Author Alexandre CARPENTIER

Bodybuilding Champion N.A.C 2012

Alexandre shares his bodybuilding experience with MegaGear blog readers

Posted in: Bodywork