The Power of Genes

If you have ever wondered why some people get more out of their training than others — with less effort and less time — part of the answer lies in genetics.

Physical fitness is shaped by many environmental factors. Training programmes, nutrition, sleep, recovery and equipment all make substantial contributions to performance. Underlying all of it, though, is your genetic makeup, which influences how your body responds to a given training stimulus.

Decades of physiological research have produced a detailed picture of how genes affect our response to exercise, and it helps explain why two people following identical programmes can see very different results.

Research has now identified over 200 genetic variants associated with fitness and physical performance traits, and work in exercise genomics continues.

Genes associated with exercise response

ACTN3 — the "speed gene"

ACTN3 codes for alpha-actinin-3, a protein found specifically in fast-twitch muscle fibres, which generate rapid, forceful contractions.

A common variant known as R577X produces a non-functional version of the protein. People with two working copies tend to be over-represented among elite power and sprint athletes, while those with two non-functional copies — roughly 18% of the population — are more common among elite endurance athletes.

It is worth keeping this in proportion: the effect on any individual is modest, and plenty of strong, fast people carry the "endurance" version. Genotype does not determine athletic outcome.

ACE

The ACE gene, involved in blood pressure regulation, has an insertion/deletion variant that has been studied extensively in athletic performance. The I (insertion) variant is associated with endurance capacity, and the D (deletion) variant with power and strength — though findings across studies have been inconsistent.

AGTR2

AGTR2 is involved in skeletal muscle development and metabolism, and variants have been associated with differences in the proportion of fast-twitch to slow-twitch muscle fibres — and therefore with a tendency toward power or endurance performance.

AMPD1

AMPD1 codes for an enzyme found in skeletal muscle and involved in energy metabolism during exercise. Reduced-function variants are associated with slower recovery and, in some people, more post-exercise muscle discomfort and fatigue.

PPARGC1A

Often discussed alongside these, this gene influences mitochondrial development — relevant to aerobic capacity and how readily your body adapts to endurance training.

What this does and does not mean

Genetic testing can indicate whether you may be naturally better suited to power-based or endurance-based activity, and how quickly you might recover between sessions. That can be genuinely useful for structuring training and setting expectations.

What it cannot do is predict athletic success, tell you what you are incapable of, or override training. The gap between a trained and untrained version of the same person is far larger than the gap created by any of these variants. Consistency, progressive overload, sleep and nutrition remain the dominant factors.

Treat genetic insight as one input into how you train — not a verdict on what you can achieve.

Fitness genetics with Rightangled

Rightangled's DNA tests examine markers relating to muscle fibre type, endurance and power response, recovery and injury risk. Results are reviewed by our clinical team, which includes GPhC-registered independent prescribers, with medical oversight from our doctor, Dr Abdullah.

Our blood tests can also assess iron, vitamin D and other markers that directly affect training performance and recovery.

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