Have you ever wondered why your sibling is more powerful than you in Karate but you’re a faster runner? Or why your basketball game was never as good as your cousin’s?

Or why the world’s top soccer players aren’t also the best weightlifters? What makes some people more athletic than others? What makes some athletes better than the rest?

Well, many factors contribute to answering such questions, and among the most prominent ones is genetics.

Your genetic code can affect your speed, endurance, muscle mass, height, and a lot more aspects that play different roles in determining a person’s sports performance.

Interested? Then keep reading!

What Genetic Factors Affect Sports Performance?

As humans, we have about 20,000 genes. Because we each don’t get the exact same genes or the exact same combination of genes, we can each be our own individual selves.

As a result, we get an extremely wide range of human phenotypes with different skeletal structures, muscle strengths, lung capacities, heart sizes, tendon elasticity, and so on.

Each of these is the outcome of the interaction between a unique set of genes, and each of these has an impact on a person’s physical performance.

Within families and even between twins, studies on the similarities and differences in athletic abilities suggest that 30 to 80 percent of the variations related to sports performance among individuals are directly linked to genetic factors.

The study of genetics on athletic performance is truly awe-inspiring. Although a lot more research is still required to conclusively establish relationships between some genes and exercise and be able to use them in predicting success in sports, many of the existing findings are highly promising.

How Genetics Affect Your Endurance

The first genetic factor to ever be linked to human athletic performance is known as ACE I/D polymorphism. It was studied as early as 15 years ago!

This genetic factor is responsible for the production of a certain enzyme that regulates body fluids.

By regulating the amount of liquid inside the body, this genetic factor also helps control blood pressure.

This genetic factor exists in two forms known as the D allele and the L allele.

If a person has the D allele, an enzyme known as ACE is more active in their body. When the ACE enzyme is more active, the body is more oriented toward power and strength performance.

If a person has the L allele, the ACE enzyme is less active in their body. When the ACE enzyme is less active, the body is more oriented toward higher endurance and exercise efficiency.

  • 25 studies on the relationship between this gene and athletics performance found a strong connection between it and endurance performance.

How Genetics Affect Your Strength & Power

“ACTN3” is a gene responsible for the formation of a certain protein within the body. This protein exists only in the type of muscles that humans use when performing explosive activities.

Sometimes, a mutation happens and the “ACTN3” gene loses a part of its original structure. This means that the gene can exist in a compete or incomplete form.

The complete form of the gene is useful in boosting power. Elite power athletes have it inside their bodies.

On the other hand, the incomplete form of the gene is linked to individuals with lower muscle strength and sprinting ability.

A 2012 study of these connections was conducted in 3 groups of elite European athletes. It showed the following results:

  • Power athletes were about 50 percent less likely to have the incomplete form of the gene.
  • Endurance athletes were almost 2 times more likely to have the incomplete form of the gene.
  • In endurance athletes, the odds of world-class competitors having the incomplete gene was about 4 times bigger compared to athletes competing at a lower level (national).

What’s more, 23 studies on the relationship between the ACTN3 gene and athletic performance showed that people carrying the complete form of the gene have higher chances of effective performance in power-oriented exercise.

This further supports the connection between the ACTN3 gene and power sports performance.

Man holding dumbbell during exercise

How Genetics Affect Injury and Recovery

An individual’s ability to resist an injury or recover from it is a crucial aspect of optimal athletic performance. This ability can be affected by genetic factors.

The relationship between genes and tendon injuries, as well as the relationship between genes and concussions, have been studied more than other types of injuries.

That’s because tendon injuries and concussions can significantly interrupt training time, which slows or stops skill development.

Additionally, tendon injuries and concussions can cause life-long health problems in athletes.

How Genetics Affect Tendon and Ligament Health

Problems in collagen are the main culprit behind tendon injuries. Collagen is the main component in the structure of tendons and ligaments.

As such, the genes responsible for the formation of collagen are factors that can increase or decrease the risk of sustaining a tendon disorder.

How Genetics Affect Concussions

When it comes to concussions (which are classified as mild traumatic brain injuries), they’ve been linked to a gene called APOE.

One of the forms of the APOE gene is believed to increase the risk of concussions and more severe injury outcomes.

  • A 1997 study on 89 patients revealed that individuals carrying this form of gene ended up with more severe outcomes from a head injury.
  • Another study involving 30 boxers showed that those who possess this form of gene scored higher on the clinical rating scale of chronic brain injury (CBI scale). This means they sustained more severe brain injuries.

How Important Are Genetic Factors to Athleticism-related Traits?

The degree of importance of genetic factors in the presence or appearance of a trait is known as heritability.

Here are some examples of the importance of genes in athleticism-related traits:

  • Height, which is crucial for success in some sports, is a highly heritable trait. The degree of importance of genetic factors in height is around 80 percent.
  • The mesomorphic and ectomorphic body types (explained below) are highly affected by genes.
  • The degree of importance of genetic factors in demonstrating athletic prominence is estimated at around 66 percent regardless of sport.
  • The degree of importance of genetic factors for muscular power and strength ranges between 30 and 83 percent (depending on the type of muscle).
  • The degree of importance of genetic factors in demonstrating aerobic endurance or VO2 max (the maximum amount of oxygen that a person can use during intense exercise) is approximately 50 percent.

Does Height Affect Weightlifting Performance?

Yes, height can affect an individual’s weightlifting performance. While the common belief is that shorter athletes can lift more weight compared to taller athletes, things aren’t so simple.

A shorter lifter can be better at certain types of lifts whereas a taller lifter can be better at other types of lifts. Additionally, the broadness of your frame gets a say in your ability to execute some lifts.

Here are a few examples:

The Deadlift

Man and woman doing deadlifts

In this type of lift, an athlete with a shorter torso and longer arms tend to perform better because they can keep the bar closer to their core and can keep their back more upright. This also helps reduce stress on the lower back.

The Squat

Shorter lifters tend to have the edge in this type of lift because they don’t have to go as far down to break parallel and then get back up.

A long torso paired with short legs means that the lifter has less range to squat through and can better maintain an upright stature while squatting.

Consequently, shorter lifters can more efficiently use their legs’ power in keeping the bar on the same plane as the heels and preventing knee rotation.

How Does Body Type Reflect on Athletic Performance?

Determining an individual’s body type and then designing a training program tailored to said type is one of the ways we can assess and improve their athletic prowess.

But what’s a body type, you ask?

A body type, also known as a somatotype, is a category that a person’s physical form falls under. This category is defined based on parameters including stature, shape, and muscle mass.

Generally, there are 3 main types of the human body to look out for: ectomorph, endomorph, and mesomorph. The concept of a somatotype was first developed scientifically by the American psychologist William Herbert Sheldon in the early 1940s.

A human’s body can be any one of these 3 somatotypes, or it can be a combination of the traits of two or all 3 types. An individual can even train in special programs to transition from one body type to another.

To recognize these somatotypes, you need to be familiar with the characteristics of each one.


Individuals with an ectomorph body type tend to

  • Possess longer limbs
  • Be skinny with little body fat
  • Have narrower shoulders than hips
  • Not be visibly muscular or not have a high lean muscle mass (even ectomorphs with extensive lean muscle mass have a different muscle distribution that’s non-defined unlike wrestlers or bodybuilders)
  • Experience difficulty in gaining weight

The ectomorph body type is frequently seen in long-distance runners as their uniquely developed long muscle mass is quite adaptable for such athletic activity.

Not to mention, the limitations of weight gain in ectomorphs offer an advantage in preserving their performance in these sorts of sports.


Individuals with an endomorph body type tend to

  • Possess a stocky physique
  • Have a more curvy outline
  • Have shoulders and hips of roughly the same width
  • Possess a broader bone structure
  • Experience a hard time keeping their body fat reduced
  • Experience difficulty in losing weight
  • Gain weight easily

You may jump to the conclusion that endomorphs are mostly obese individuals, but that’s not true. Many active athletes and runners are endomorphs.

That said, individuals with an endomorph body type need to pay extra attention to exercise and diet than the other somatotypes because they’re more prone to holding onto weight.


In the middle, between ectomorphs and endomorphs, individuals with a mesomorph body type tend to

  • Possess a medium bone structure
  • Have a more even outline with a squarish look
  • Have wider shoulders than hips
  • Experience a relatively easy time when it comes to building muscles
  • Experience a relatively normal time gaining and losing weight
  • Possess more elongated torsos coupled with shorter limbs

Generally speaking, mesomorphs have bodies that are naturally oriented toward athletic performance, especially activities that call for speed and energy explosions.

That’s because the mesomorph body type has muscles with a characteristically high percentage of fast-twitch tissues. These muscles can quickly and intensely release energy.

It may seem that mesomorphs have everything going for them, but they do need to put effort into establishing a balance between their tendency to easily put on weight and their ability to build lean muscle mass.

How Are Human Feet Built for Athleticism?

The feet play a critical role in the movement of the body, so it’s no surprise that the way they’re built is optimized to enhance athletic performance.

  • In volleyball and basketball, feet serve as launching pads for jumps.
  • In running sports such as soccer and football, feet propel and cushion you as levers and springs would.
  • In aerobics and tennis, feet act as pivots and brakes.

Even the shape and length of the toes on your feet can provide insight into your athletic prowess according to sports performance experts.

For example, if your first toe (big toe) is longer than your second toe, you’re likely to be naturally talented in certain sports such as sprinting and skiing.

That’s because a longer first toe enables you to lean your body weight onto it more effectively, which is necessary for grounding techniques in skiing and sprinting.

The type of foot arch can also affect sports performance. For example, in short-distance running, athletes with high arch feet demonstrated improved speed and dynamic balance compared to neutral and low arch feet.

What’s even more fascinating is that scientists have found that running barefoot is possibly healthier than when wearing shoes!

Barefoot running lets you avoid heel striking by directing your body to land on the middle or ball of the foot instead.

What Makes East African Runners So Good?

Black runner starting a race

Long-distance runners from Kenya and Ethiopia dominate the sport, holding more than 90 percent of the current top-ten world ranking and all-time world records.

The brilliant success of Kenyan and Ethiopian athletes has been attributed to multiple factors, among which lies genetic predisposition.

The International Journal of Sports Physiology and Performance published an article in 2012 that suggests the presence of many genes that contribute to Kenyan and Ethiopian elite running performance.

However, more research is yet to be done to identify unique genetic characteristics.

Wrapping Up

There you have it! A guide to scientific-backed fun facts about genetics and exercise.

As you can -hopefully- tell by now, an individual’s genetic composition clearly has an effect on their athletic performance.

Your genes can grant you the natural tendency to run faster, jump higher, be more flexible, or work out for longer. It can help you build more muscle, lift heavier weights, or deliver more power.

But don’t forget that you still have to train to utilize any genetic advantage you may have in any sport.


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