[Expert Explanation] Is Over 60% of Athletic Ability 'Genetic'? The 'Talent' and Sports Aptitude Written in Your DNA

Rewritten on: April 2, 2025

Around 66% of athletic ability is said to be determined by genetic factors, with genes such as ACTN3 and ADRB2 influencing explosive power and endurance. This article explains how genetic testing can reveal your own traits and help you choose the right sport and design the best training.

Last updated: 2026.01.06

"That kid has such natural athletic ability" — it's a phrase often heard on the sports field, but its true source may lie in the "genes" inherited from parents. With the rapid advances in molecular genetics and sports science in recent years, individual physical traits are increasingly being explained at the DNA level. By using the latest analysis technology, a scientific approach is now possible for choosing the optimal sport, designing efficient training, and even preventing injuries. In this article, we bring you the latest research data on the relationship between athletic ability and genetics, explain the major genes involved in explosive power and endurance, and show how genetic testing can help expand the possibilities for you and your family.

Shocking research results on athletic ability and genetics

Athletic ability and genetics are connected more deeply than we might imagine. In a large-scale twin study conducted by the Vrije Universiteit Amsterdam in the Netherlands, individual differences in "athlete status" (the level of competitive performance) were analyzed among 4,488 twins. The results estimated that about 66% of individual differences in competitive performance were attributable to genetic factors [ref:1]. In other words, two-thirds of the gap between top athletes and everyone else may stem from inherited genetic traits.

Furthermore, a genome-wide linkage analysis of 700 dizygotic twin pairs scientifically demonstrated that specific regions on human chromosomes 3 and 4 are strongly associated with physical activity levels and fitness indicators [ref:1]. These chromosomal regions are concentrated with genes that encode proteins governing muscle structure and metabolic efficiency, and are thought to form the "foundation" of athletic ability.

These findings show that athletic ability is not determined by "effort" or "environment" alone. Of course, the importance of training volume, nutrition management, and mental training remains unchanged, but building a training strategy that accounts for one's genetic traits leads to maximizing performance. In recent years, national teams and professional sports clubs around the world have increasingly used athletes' DNA information to introduce individually optimized training programs [ref:4].

By type! The genes that determine performance

So specifically, which genes affect athletic ability? More than 200 genes have been reported to date as related to sports performance, but here we introduce some of the most influential and representative ones.

The key to explosive power: the ACTN3 gene

The most famous is the "ACTN3 (alpha-actinin-3)" gene. ACTN3 encodes a protein specifically expressed in fast-twitch muscle fibers (type II fibers) and plays an essential role in high-speed, high-power muscle contraction. The ACTN3 gene has a variant called the R577X polymorphism; people with the RR genotype have fast-twitch fiber function fully expressed, giving them a high aptitude for explosive sports such as sprinting, jumping events, combat sports, and weightlifting [ref:2].

On the other hand, people with the XX genotype (in which no ACTN3 protein is produced) have lower absolute power in fast-twitch fibers, but their slow-twitch fibers become relatively dominant, giving them reportedly higher aptitude for endurance sports such as marathon running, triathlon, and long-distance swimming [ref:2]. In fact, multiple studies have confirmed statistically that Olympic-level sprinters have a significantly higher rate of the RR genotype than the general population, while elite long-distance runners have a higher proportion of the XX genotype.

The source of stamina: the ADRB2 and PPARGC1A genes

Representative genes affecting cardiorespiratory endurance (stamina) include "ADRB2 (beta-2 adrenergic receptor)" and "PPARGC1A (PGC-1 alpha)" [ref:3]. ADRB2 encodes a receptor that regulates bronchodilation and fat breakdown; people with certain polymorphisms have higher oxygen uptake efficiency during exercise and show an advantage in prolonged aerobic exercise.

PPARGC1A is also known as the "master regulator of mitochondria," controlling the efficiency of mitochondrial biogenesis and oxidative phosphorylation. People with high activity of this gene have superior energy conversion efficiency in the body, and it has been found that they gain a greater improvement in endurance from the same amount of training [ref:3]. In sports involving prolonged energy expenditure, such as marathon running and road cycling, the genetic type of PPARGC1A is thought to significantly affect performance.

Other notable genes

Besides the genes above, many other genes are involved in athletic ability. Here are some representative examples.

• ACE gene (angiotensin-converting enzyme): Has an I/D polymorphism, where the II genotype is said to favor endurance sports and the DD genotype favors explosive sports [ref:5].
• VEGF gene (vascular endothelial growth factor): Promotes capillary formation and affects the efficiency of oxygen supply to muscles.
• COL5A1 gene: Relates to connective tissue flexibility and has been reported to be associated with injury risk in tendons and ligaments.
• MCT1 gene: Involved in the rate of lactate clearance, affecting recovery from high-intensity exercise.

These genes do not function alone; they interact with each other in complex ways to determine overall performance. For this reason, no single gene can definitively determine whether someone is "suited" or "not suited" to a sport, and it is important to comprehensively analyze multiple genes together.

Comparison of major athletic-ability-related genes

Genetics alone doesn't decide everything — the role of environment and training

While about 66% of athletic ability is said to originate from genetic factors, the remaining approximately 34% is determined by environmental factors. Environmental factors here include daily training content, nutrition intake, sleep quality, mental support, the quality of coaching, and the quality of training facilities, among many other things.

For example, even someone who is genetically predisposed to excel in endurance will not fully realize that ability without an appropriate training program. Conversely, even someone who is genetically an explosive-power type can improve their endurance to some degree through training. What matters is accurately understanding your own genetic tendencies and building the optimal training strategy suited to them [ref:6].

Recent research in epigenetics has also revealed that exercise and nutrition can change the "expression pattern" of genes. In other words, even though the genes themselves cannot be changed, how actively they function may be controllable through daily lifestyle habits and training.

Know your own "blueprint" and expand your possibilities

Of course, genetics is not everything, but knowing your own genetic traits can serve as a "compass" for bringing out your talent to the fullest. For parents who are wondering what extracurricular activities or sports to choose for their children, getting advice based on objective data can also be a great source of reassurance.

With seeDNA's "DNA Score," you can learn about the genetic tendencies of your "athletic ability," including explosive power and endurance. It analyzes multiple related genes at once, including ACTN3 and ACE, to scientifically evaluate which type of exercise your body is suited for.

The "DNA Score" genetic test, which lets you check everything from health risks to talent and constitution in a single test, is a simple test you can do at home just by swabbing the inside of your cheek. It's completely painless, so even small children can take it safely. Results are available in as little as 3 days, allowing you to put them to use right away in your training plan or lifestyle improvements. Why not use the power of science to explore the possibilities for you and your family?

Benefits and process of using genetic testing

Genetic testing offers a wide range of benefits. Here are the main points.

• Optimal sport selection: Find a sport suited to your child's genetic traits and help their talent grow efficiently.
• Personalized training: Understand whether they are an explosive-power type or an endurance type, and design an efficient training menu.
• Injury prevention: Use genetic information related to connective tissue to identify injury risk in advance and take preventive measures.
• Increased motivation: Self-understanding based on scientific evidence supports a positive attitude toward training.
• Application to health management: Learn not only about athletic ability but also lifestyle disease risks and constitutional tendencies, allowing you to build a comprehensive health strategy.

The DNA Score testing process

1. Apply and purchase the test kit via the official website or by phone.
2. Use the test kit delivered to your home to gently swab the inside of your cheek and collect a sample.
3. Send the sample to the seeDNA Genetic Medical Research Institute using the enclosed return envelope.
4. The institute performs DNA analysis and delivers the results report in as little as 3 days.
5. Use the results to consider the optimal sport and training plan for yourself or your child.

／Discover your genetic tendencies for athletic ability／

Frequently Asked Questions

Q1. How much of athletic ability is determined by genetics?

A. According to a large-scale twin study, about 66% of individual differences in competitive performance are estimated to be due to genetic factors [ref:1]. The remaining approximately 34% is influenced by environmental factors (training, nutrition, sleep, etc.). Although genetics accounts for a large share, it is fully possible to improve ability through proper effort and environment.

Q2. What is the ACTN3 gene?

A. ACTN3 is a gene that encodes a protein called alpha-actinin-3, which is specifically expressed in fast-twitch muscle fibers. People with the RR genotype excel at fast muscle contraction and are suited to explosive sports such as sprinting and combat sports. People with the XX genotype tend to have higher aptitude for endurance sports and often excel at marathon running and long-distance swimming [ref:2].

Q3. Can genetic testing reveal sports aptitude?

A. Yes. By analyzing multiple athletic-ability-related genes such as ACTN3, ACE, ADRB2, and PPARGC1A, you can learn about genetic tendencies such as whether you are an explosive-power type or an endurance type. seeDNA's "DNA Score" analyzes these genes all at once and delivers a sports-aptitude report based on scientific evidence.

Q4. Can children take a genetic test too?

A. Yes, children can take the test safely as well. The test is a simple method done at home by gently swabbing the inside of the cheek, and it is completely painless. Many parents use it as a reference when choosing extracurricular activities or sports for their children.

Q5. Can I still improve at a sport that my genes are not suited for?

A. Of course you can. Genetic testing only shows a "genetic tendency" and does not negate the effect of effort or training. Even with genetically unfavorable factors, you can still reach a very high level through proper training, nutrition management, and mental care. It is best to use genetic information as "a map for finding the shortest route."

Q6. How long does it take to receive the test results?

A. seeDNA's "DNA Score" delivers results in as little as 3 days after the sample arrives. From applying for the test kit, to returning the sample, to receiving the results report, everything can be completed from home, making it convenient even for busy people.

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