Genetics Of Sprinting - Are Sprinters Born Or Made?
A popular question in coaching and training circles is whether sprinters are born or made.
To assess how much of a role genetics play in sprinting ability, I will discuss some research on the topic and my experience as a track & field coach and competitive sprinter in this article.
What This Article Will Cover:
- Is Sprinting Speed Genetic
- Twin Studies
- Genetic Variants Related To Sprinting
- Sprinting-Related Factors Affected By Genetics
Is sprinting speed genetic?
Sprinting speed is determined in part by genetics and heritable characteristics but is also influenced strongly by exposure to sprint training and athletic activity early in an athlete's life.
The athletes I have coached who played sports and lived an active lifestyle from a young age are typically faster and respond better to training than athletes who have never trained for sports before showing up to run for my team.
When I was a kid, my dad would take me on runs with him, where he would sprint on the beach, and I would hold onto his shirt to keep up. Essentially, I was doing assisted sprint training when I was a young child. I was already faster than my peers then, but this non-structured training I was exposed to at a young age helped me become a faster sprinter than I otherwise would have been.
Twin Studies
Research on families and twins can help us identify whether sprinting speed relies on genetics.
A study by Alonso et al. found that concerning 30-meter sprint performance, 73% of one's sprinting speed can be explained by genetics. Heritability was higher in women at 85%, while men showed that 67% of their performance was likely attributable to genetics.
Some limitations to this study should be considered.
First, this study only looked at 30-meter sprints, which is a test of acceleration ability rather than maximal velocity sprinting. Further, this study did not analyze competitive sprinters, so it only shows baseline sprinting abilities rather than elucidating how much of a role genetics play in how fast an athlete can run if they are exposed to sprint training.
In coaching and competing in the sprints, I have seen athletes who are faster than average when they begin training but fail to see progress. In other cases, athletes were not as fast when they started out, but they were able to progress significantly after going through quality sprint training.
For example, this year, one of the sprinters I coach has dropped from 12.03 seconds to 11.35 seconds, while our fastest sprinter has only improved by one-tenth of a second. With nearly equal times but a significant difference in their progress
Because of this, I would take these percentages of heritability with a grain of salt, as they do not speak to one's sprinting potential if they train to get faster; it only suggests how much of a role genetics play in an athlete's baseline acceleration ability.
Genes That Affect Speed
ACTN3 Protein
The ACTN3 gene is responsible for encoding the α-actinin-3 protein, which is primarily found in Type II (fast-twitch) muscle fibers. Individuals with the ACTN3 557XX genotype don't produce any α-actinin-3 and tend to have a higher ratio of Type I (slow-twitch) muscle fibers compared to those with the ACTN3 557RX or ACTN3 557RR genotypes.
A 2003 study examining 107 elite sprint/power athletes found that only 5.6% had the 577XX genotype, compared to 18.3% of a control group and 23.7% of a group of elite endurance athletes.
Another study with 299 elite Japanese athletes discovered a notable difference between 577RR+RX and XX athletes, with faster 100m times for RR+RX athletes. A 2016 multi-cohort study confirmed these findings, showing that 577RR athletes had significantly faster average 200m times compared to 577XX athletes. This research suggests that the ACTN3 genotype accounts for 0.92% of sprint time variance.
The occurrence of the ACTN3 577XX genotype varies among ethnicities, with the highest prevalence being 25% in Asian populations. African Bantu populations have the lowest incidence, with less than 1% having the 577XX genotype.
I personally have one copy of the ACTN3 gene, and I am faster than the average person.
ACE Gene
The ACE gene is responsible for encoding the angiotensin-1 converting enzyme. Individuals with the ACE-I variant have lower ACE levels than those with the ACE-D variant. However, it is unclear how ACE levels might influence sprint performance.
Nonetheless, a study of British Olympic-standard athletes found that the frequency of ACE-I athletes increased with distance: 62% of runners in 5k races and above had the ACE-I variant, compared to only 35% of sub-200m sprinters (49% in a control group).
A similar study of Russian athletes revealed an excess of ACE-D variants among short-distance athletes compared to medium- and long-distance athletes and a control group. The same multi-cohort study mentioned earlier discovered an association between ACE variants and speed, with ACE DD/DI athletes being significantly faster than ACE II athletes over 200m, explaining 1.48% of sprint time variance.
Only one study measured the prevalence of the ACE genotype across ethnic groups, revealing that 24.7% of Caucasians had the ACE II genotype, compared to 82.8% of Samoans and 16.2% of Nigerians.
What Factors Important To Sprinting Are Influenced By Genetics
One problem I have with the question of the importance of genetics in sprinting is that usually, this is discussed broadly without digging down to any specifics.
When talking about genetics in sprinting, some of the qualities of athletes that are influenced by genetics can include the following:
- Limb Length
- Muscle and Tendon Qualities
- Tendon Insertions
- Muscle Fascicle Length
- Pennation Angles
- Fast Twitch Muscle Fiber
- Hormone Production
- Nervous System Wiring
- Aggression & Confidence
Many of these factors can be influenced by training, but genetics will determine how much potential one has with regard to force production, tendon elasticity, injury risk, etc.
My Verdict
Ultimately, it is my belief that one's ultimate potential in sprinting is limited by their genetics, but everybody has the ability to sprint faster.
Whether you run 11 seconds or 15 seconds in your first-ever 100-meter dash sprint, you can get faster if you train consistently and optimize your sprint training program.
Feel free to use the resources about sprinting on this website, as well as check out my YouTube channel and Instagram accounts for more information on how to sprint faster.