Why can some individuals run faster, jump higher, or endure longer than others? Hard work, training, and determination? Yes, of course, they do play a big role. But behind this athletic superpower lies another secret entity: the ACTN3 gene. This gene plays a significant role in influencing athletic performance. But here’s the twist: people carry different types of this gene, each of which supports different athletic parameters. Read on to understand the deep-rooted connection between the ACTN3 gene and your athletic performance.
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What Is ACTN3 Gene?
The ACTN3 gene provides instructions to produce the alpha-actinin-3 protein present in fast-twitch muscle fibers.
Fast-twitch muscle fibers contract quickly and help perform high-intensity activities for short intervals.
Fast-twitch muscle fibers rely on anaerobic respiration for muscle contraction.
The ACTN3 gene can have variants, which is quite common among the general population.
About 20-30% of the general population have this mutation.
It usually does not have any harmful effects on general health and well-being.
However, the genotype of the ACTN3 gene can affect one's athletic performance.
What Does It Do?
Skeletal muscles are attached to the bones and help in movement.
Each functional unit of a skeletal muscle is called a sarcomere.
The sarcomere is made of two types of filaments: actin and myosin.
The ACTN3 gene encodes the alpha-actinin three proteins.
It is found in fast-twitch muscle fibers.
The fast twitch muscle fibers produce powerful, explosive bursts of speed.
Such powerful muscle contractions are needed in deadlifting, sprinting, and speed skating.
What Are The Types Of ACTN3 Gene?
ACTN3 gene can have a variant or mutated form.
Those without the variation have the genotype R/R, while those with the mutation can have either R/X or X/X genotype.
Muscle Fibers and Genotypes
The ACTN3 gene's genotype determines the composition of the fast twitch muscle fiber.
The presence of either the R/R, R/X, or X/X genotype determines the amount of alpha-actinin-3 protein present in the fast-twitch muscle.
The ACTN3 genotype and an individual's athletic performance are linked in the following way:
- R/R: power advantage, associated with fast-twitch muscle fibers
- R/X: endurance advantage
- X/X: contributes to both power and endurance, associated with slow-twitch muscle fibers.
ACTN3 Gene for Athletic Performance
ACTN3 gene is only expressed in fast twitch muscles and is essential for anchoring actin.
It also regulates the coordination of muscle fiber contraction.
The R/R and R/X genotype of the ACTN3 gene is associated with sprint performance, while the X/X genotype is associated with endurance performance.
ACTN3 And Muscle Power
The ACTN3 gene encodes the alpha-actinin-3 protein.
This protein is found in fast-twitch muscle fibers and generates explosive muscle power.
Several studies have shown the presence of the R/R genotype in sprint athletes.
The R/R genotype of the ACTN3 gene is associated with explosive muscle power, while the X/X genotype is associated with less muscle power.
Notably, the R/X genotype showed no association with power athlete status.
ACTN3 and Exercised-induced Muscle Damage
Damage to skeletal muscles from a sudden, intense workout is called exercise-induced muscle damage.
It is more common in people who are not accustomed to regular exercise.
Exercise-induced muscle damage is accompanied by delayed onset muscle soreness and leakage of intramuscular proteins into the blood.
Individuals with the X/X genotype are more prone to experience exercise-induced muscle damage than those with the R/R genotype.
Studies show that such individuals had higher serum markers of muscle damage after working out.
Also Read
Is delayed onset muscle soreness a sign of muscle growth?
ACTN3 and Handgrip Strength
Handgrip strength is often used to measure muscular fitness.
Higher grip strength indicates better recovery after a fracture and lowered grip strength is often associated with old age.
The Actn3 KO mice mimic the X/X genotype of the ACTN3 gene in humans.
Studies have shown that the Actn3 KO mice have significantly lower grip strength and increased recovery from fatigue.
This pattern is very similar to what is seen in human muscles deficient in the ACTN3 gene.
Do All People Have The ACTN3 Gene?
Everyone has two copies of the ACTN3 gene.
One is the working copy, which produces a protein called 577R, and the other is the non-working copy called 577X.
The more working copies of the ACTN3 gene you have, the better your athletic performance.
So, if you have the R/R genotype of the ACTN3 gene from both of your biological parents, you are likely to be a good athlete.
If neither of your parents had a working copy of the gene, you likely have the X/X genotype of the ACTN3 gene.
How To Train According To My ACTN3 Gene Type?
Athletic performance can be strongly influenced by genetics.
But it cannot necessarily predict success.
Having the sprinter gene in your cells does not mean you will be an elite sprinter.
It just means that you will perform better in sprint or power events.
You still need to undergo optimal training to achieve success as a sprinter.
It also means that you need to work harder as an endurance athlete.
Psychological and environmental factors influence athletic performance.
Optimal nutritional practices often compensate for not having the athletic gene.
People with the R/R and R/X genotypes who have high strength and power should ideally choose high-load-low-repetition workouts.
On the other hand, people with the X/X genotype should choose workouts with low load and high repetition.
Individuals with the R/R or R/X genotype are more resistant to muscle damage and should choose high-intensity intermittent training.
Individuals with the X/X genotype should go with low-intensity, high-volume training.
How Do I Know If I Have ACTN3?
A simple blood test can reveal if you have a functioning copy of the ACTN3 gene.
You will need our doctor's prescription and valid identity proof to undergo the test.
The test report is usually delivered within eight days of collecting the blood sample.
Summary
The ACTN3 gene encodes a protein and is found in fast-twitch muscle fibers.
It is associated with sudden explosive muscle power and is said to influence athletic performance.
The ACTN3 gene has three variations: R/R, R/X and X/X.
The R/R genotype is associated with more muscle power and handgrip strength, while the X/X genotype is associated with more muscle damage during exercise.
Having the ACTN3 gene means that you might be a good sprinter.
You still need to undergo training and practice to succeed as an athlete.
Proper training, nutrition, and the ACTN3 gene will help you succeed as an athlete.
References
https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/actn3
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741991/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7404684/
https://pubmed.ncbi.nlm.nih.gov/28154975/
