With enough training, a perfect diet, mental fortitude, and the right equipment… and any of us could be an elite athlete, right? While I would like to say, “of course, you can do anything!”, it turns out that genetics plays a role in athleticism as well.
Do genes affect athletic performance?
After reading through a bunch of studies on the genetics of elite athletic performance, I’ve come away with an overall sense that for some people, athleticism will just come easier. For others, it will take a little more work.
To be honest, your genes are probably not the limiting factor for your athletic performance unless you are at the very top of your sport. Even at the top levels, there are always exceptions.
Moreover, reading through some of the research leaves me a bit disconcerted. Some of the research reads as almost a ‘how-to’ guide for selecting people for a sport based on their genetic profile.
First, a couple of terms to define:
Power sports are generally ones that require short bursts of power. Examples include sprinting, weight lifting, short track biking, and gymnastics. Generally, these sports require more anaerobic muscle power.[ref]
Endurance sports include long-distance running, distance cycling, long-distance swimming, and cross-country skiing.
While the genetic variants listed below may make a difference between winning or not at the Olympic level, don’t let the lack of a ‘good’ genetic variant dissuade you from a sport you love.
Why do some people build muscle faster?
Muscle composition is partly genetic. We all know people who put on muscle easily, and other people who are long and lean, well suited for running. This doesn’t mean that people who are long and lean can’t put on some muscle mass with weight lifting, but it does mean that they may not put on as much muscle mass as quickly as others.
How much does genetics play a role in muscle building?
The composition of muscle fiber (slow-twitch vs fast-twitch) has been shown to be about 45% due to genetics and about 40% due to the environment (exercise, nutrition, etc.).[ref]
Studies show that the amount of slow-twitch (Type I) muscle ranges from 5 – 90% in thigh muscles. Slow-twitch muscle is best suited for long endurance and aerobic exercise – for example, long-distance runners. Type IIX muscle fibers (fast-twitch, glycolytic) are more suited to power sports and strength training.[ref]
Genetic variants that impact muscle composition:
This section covers the research on different genetic variants that impact muscle composition, such as muscle fiber type and muscle development. Additionally, I’ve written another article on ACTN3 and ACE genes.
The renin-angiotensin system regulates fluids and blood pressure in the body through the release of renin from the kidneys.
The AGTR2 gene codes for the angiotensin 2 receptor involved in blood pressure homeostasis – and in the development of skeletal muscle.
Studies on AGTR2:
- A study of 600+ Brazilian athletes compared with a similar group of non-athletes found the AGTR2 rs11091046 A allele slightly more often in power athletes than in the control population.[ref]
- A meta-analysis of several population groups of elite and Olympic athletes found the rs11091046 C allele more often in elite sprint/power track and field athletes.[ref]
- Not all studies agree: A study involving Japanese athletes did not back up those results, so the AGTR2 association may depend on the population being studied.
Check your genetic data for rs11091046 (23andMe v4)
- A/A: more fast-twitch fibers; associated with power athletes[ref]
- A/C: some studies show association with power athletes
- C/C: more slow-twitch fibers, endurance athletes[ref]
Members: Your genotype for rs11091046 is —. (Note, this is on the X-chromosome, so 23andMe data for men will only show one letter.)
Another gene within the renin-angiotensin system that has been associated with athletic performance is the AGT gene, which codes for the protein angiotensin. This protein helps to control blood pressure and electrolyte balance in the body. Angiotensin is a precursor to the angiotensin II protein, which also acts as a skeletal muscle growth factor.
Studies on AGT show:
- A study showed the C allele of the rs699 variant seems overrepresented in power athletes. The CC genotype occurred three times more often in power athletes than endurance athletes. [ref]
- A 12-week long training study using women athletes found that those with the G allele had better performance increases in power moves. Specifically, they improved more on vertical jump height than those with the AA genotype.[ref]
Check your genetic data for rs699 (23andMe v4, v5; AncestryDNA):
- G/G: increased angiotensin, risk of high blood pressure, more likely to be power athlete than endurance athlete[ref][ref]
- A/G: slightly higher risk of high blood pressure, more geared toward power athletics
- A/A: typical
Members: Your genotype for rs699 is —.
IL-6 (interleukin 6) is an important inflammatory cytokine in the immune response. In addition to fighting off pathogens, it helps with muscle repair after high-intensity exercise. An increase in IL6 seems to be an advantage for building muscle through exercise. While often we try to limit inflammation, this is one case where the inflammatory process is beneficial.
Studies on IL-6 and muscle building:
- The C allele is found more often in long-distance swimmers when compared with non-athletes and short distance swimmers.[ref]
- The G allele was found to be associated with elite power athletes when compared with groups of non-athletes or with endurance athletes.[ref]
Check your genetic data for rs1800795 (23andMe v4, v5; )
- C/C: decreased IL-6, found more often in long-distance swimmers, endurance athletes
- C/G: found in a mix of athletes
- G/G: Increased IL-6, more likely to be power athlete[ref]
Members: Your genotype for rs1800795 is —.
Myostatin is a peptide secreted by skeletal muscles and regulates the increase in muscle mass. The MSTN gene codes for the myostatin protein. Basically, increased myostatin inhibits muscle growth.
Double-muscled cattle (right) are caused by a mutation in the myostatin gene that decreases myostatin production. (If you are wondering why all cows aren’t bred to have the double myostatin mutation, it also causes increased problems with pregnancies and the need for more expensive feed.)
Studies on the rs1805086 variant have reported the C allele is associated with greater muscle mass. This variant is found in 11-31% of African Americans and <5% of Caucasians.[ref]
A study of ‘explosive leg power’ (squats, jumps) in non-athletes found the C allele of rs1805086 linked to worse performance.[ref]
Check your genetic data for rs1805086 (23andMe v5):
- T/T: normal, better jumping ability[ref]
- C/T: associated with greater muscle mass
- C/C: associated with greater muscle mass[ref]
Members: Your genotype for rs1805086 is —.
Beyond muscles: other genetic variants that impact athletic performance
The rest of this article is for Genetic Lifehacks members only. Consider joining today to see the rest of this article.
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Debbie Moon is the founder of Genetic Lifehacks. Fascinated by the connections between genes, diet, and health, her goal is to help you understand how to apply genetics to your diet and lifestyle decisions. Debbie has a BS in engineering and also an MSc in biological sciences from Clemson University. Debbie combines an engineering mindset with a biological systems approach to help you understand how genetic differences impact your optimal health.