How does genetics impact your athletic performance? (#60)

Can your genes determine which sport you're best suited for? As genetic testing has become more accessible, interest in the link between genetics and athletic performance has increased. In this article, we explore what research says about some of the genes most commonly linked to endurance and explosiveness. Certain genetic variations seem to offer slight advantages in specific sports, but the picture is far more complex. Genes can influence your potential, but they don't determine your performance alone. Training, environment, and individual choices still play a crucial role.

Genetics – referring to genes and their connection to sports performance – is a compelling field that has drawn considerably more attention in recent years. The starting signal really launched in 2003 with the completion of the Human Genome Project HUGO, allowing us to map the human genome. It's easy to appreciate the potential benefits: picture if, in the future, we could screen individuals to identify who has a greater predisposition to become endurance athletes or powerlifters. We'll set aside the ethical debate in this text – acknowledging the pros and cons of categorizing individuals based on specific traits.

As is often the case when something new emerges in the market, commercial operators swiftly follow suit. We've observed several companies offering DNA or genetic tests, followed by advice on training, diet, and more. Rather than commenting on the business model, we'll explore the research about what genetic tests can truly reveal concerning which type of sport is best suited for you.

In sports performance, two genes have been identified with a clear connection to performance. These genes have been extensively studied over the past 17 years, and in one of the latest review articles published in 2013, results from over 450 studies were summarized. The genes are angiotensin I-converting enzyme (ACE) and alpha-actinin-3 (ACTN3). In genetics, the term polymorphism is used to describe when a gene can occur in multiple variants. ACE exists in two variants (alleles I and D). We won't dive into micro-level details here, but if you want to explore further, this study is a good starting point. If you have the I allele, you are genetically a bit more primed for endurance, while the D allele suits short, explosive activities better—sprinting or powerlifting.

The second gene, ACTN3, also exists in two main variants: the R allele and the X allele. The different genotypes (e.g., RR, RX, XX) provide different traits linked to muscle building and explosiveness.

If we were to give you a straightforward answer on which genotype favors endurance sports: it's the ACE II genotype and the ACTN3 X allele. Both are strongly linked with endurance performance. On the other hand, the ACE D allele and the ACTN3 R allele are more suited for strength and explosive sports. Naturally, there are variations and nuances — we'll delve further into the practical implications later in the text.

This doesn't mean you can relax on the couch expecting a gold medal just because you have the "right" genes. But you might have a slight advantage over those who don't possess them.

In the future, we might visit the gene bank in the city to purchase our abilities.

In conclusion, this study summarizes the connections between sport performance and the ACE I/D and ACTN3 R577X polymorphisms. The results consistently offer more solid evidence of associations between the ACE II genotype and endurance events, and between the ACTN R allele and power events.

• The ACE II allele is primarily linked to enhanced triathlon performance, while the D allele is frequently found in elite swimmers. ACE II has also been connected to better metabolic efficiency, but there's still no definitive link to maximum oxygen uptake — more research is needed in this area.

• The ACTN3 R allele codes for a muscle protein that aids in building muscle mass and explosive strength. Stronger expression of ACTN3 creates favorable conditions for becoming powerful and explosive.

The same Brazilian research team that studied the 150 males and ventilatory threshold has also begun examining other genes and their connection to running economy. In a recently published study, they examined 150 males (likely the same group) and linked the ACTN3 gene to running economy. They found that individuals with one allele of each type (i.e., RX) had the most efficient running economy. So — slightly stiffer tendons/ligaments seem to be an advantage for running economy.

There is also the COL5A1 gene, which codes for elasticity in tendons and ligaments. One of the research groups found no link between COL5A1 and running economy in their study (source), while other teams have previously found correlations. So the picture isn't completely clear yet — but it's not illogical that genetic information on tendon structure would impact running economy.

For further reading on running economy, we recommend our previous article/podcast on running economy.

Genes are something you can't change, but the topic remains fascinating—especially as commercial gene tests appear, sparking many questions. When companies begin examining ACE and ACTN3, they might find some useful insights, but:

• The results from a test tell you something, but far from everything.
• With around 20,000 genes, many likely interact to affect sports performance. Focusing solely on 1–3 genes isn't recommended.
• In practice, trying different sports to discover what you're naturally good at often works just as well.

There are definitely several poor-quality products on the DNA test market. Be cautious. Many gene tests also claim to provide dietary advice—which could be a subject for a future article if there's enough interest.

According to our Swedish gene expert, Mikael Mattsson (not the most glamorous title), we still have a long way to go before we can develop truly reliable tests, but research is progressing rapidly. (source)