Muscle Performance

Muscle Performance

Various factors determine athletic success, including genetics. Genes associated with physical performance have been a popular area of research for a number of years. There are now more than 200 genes that are thought to have a potential impact on physical performance. One of the most studied genes is ACTN3 gene which influences an individual’s ability in sprinting and endurance.

What is the ACTN3 gene?

The ACTN3 gene encodes a protein called a-actinin-3, which forms part of human skeletal muscle. More specifically, ACTN3 protein anchors together actin-containing thin filaments and stabilizes the muscle contractile apparatus.

What is the effect of genetic variation at the ACTN3?

In individuals with no SNP, the ACTN3 protein is not produced - they are ACNT3 deficient. This results in reduced muscle strength but improved endurance capability and leads to individuals being more able at endurance training, such as long-distance running, than power training, such as sprinting and powerlifting.

In individuals with an allele, the ACTN3 protein is produced. Because of this, their muscles are stronger and able to generate forceful contractions at high velocity. This leads to them being more able at power training, such as sprinting and powerlifting than endurance training, such as long-distance running.

How does ACTN3 deficiency improve endurance capability?

ACTN3 deficiency results in a shift in muscle metabolism toward a slow oxidative phenotype with increased glycogen (which is associated with endurance) from fast glycolytic phenotype (which is associated with power).

Is the ACTN3 gene an example of an evolutionary trade-off?

Yes, the ACTN3 gene is an example of an evolutionary “trade- off” between performance traits for speed and endurance activities.

The presence of a-actinin-3 has a beneficial effect on the function of skeletal muscle and evolutionary advantage because of increased sprint performance. Whilst having no ACTN3 is associate with improved endurance capacity. As both have benefits, both were selected for during human evolution.

Is ACNT3 expression associated with elite athletes?

Yes. The allele that produces ACTN3 is overrepresented in elite strength athletes.

Are individuals that produce ACTN3 predisposed to higher rates of injury?

Yes. ACTN3 expression is linked to increased risk of muscle damage because muscle contraction is more powerful. Individuals that produce ACTN3 should therefore be extremely careful and ensure that they stretch properly before and after exercise.

Backed by Science

Our in-house scientists have sorted through thousands of studies and we only use genes that are backed by a significant body of peer-reviewed research. Check out Nell’s Science Standard for more information.