How Much Does Talent (Genetics) Affect Your Running Performance?

Have you ever seen someone who trains less than you — or hasn’t been running long — and yet runs noticeably faster? It’s a humbling experience, and it raises an uncomfortable question: how much does natural talent actually matter?

The short answer, backed by research, is that genetics plays a significant role in endurance performance outcomes.

Some people are born with a muscle fiber composition that naturally favors long-distance running. Others carry the “high responder” trait — a genetic predisposition that amplifies the benefits of the same training load.

That said, there’s an equally important flip side: there is always room to improve through your own effort.

In this article, we explore the relationship between endurance performance and genetics, and break down which key factors you can actually improve through consistent training.

Three Key Factors That Determine Endurance Performance

Three performance markers are widely recognized as the primary determinants of long-distance running performance: ① VO2 max, ② lactate threshold, and ③ running economy※1.

Understanding how each of these factors responds to training — and which one needs the most attention — is the foundation of smart, long-term improvement.

Below, we examine how much each factor can realistically improve through training.

How Much Can Training Improve VO2 Max?

Let’s start with VO2 max and look at just how much training can move the needle.

VO2 Max and Genetics

VO2 max is strongly shaped by genetics. In a landmark large-scale study of 481 participants — the HERITAGE Family Study — all subjects followed the same 20-week training program, yet showed vastly different gains in VO2 max. Researchers found that approximately 47% of the variation in training response was explained by genetic factors※2.

The graph below plots training duration on the x-axis and VO2 max on the y-axis.

Individuals like curve ⑤ are known as low responders — people who see relatively little improvement despite consistent training. In some cases, VO2 max may improve by as little as 5%, regardless of how hard they train.

At the other end of the spectrum, individuals like curve ① are called high responders. They not only start with a naturally high aerobic capacity, but also extract significantly more benefit from the same training stimulus.

High responders can improve VO2 max by as much as 50% through training※2. It follows that the elite athletes competing at the Olympics and World Athletics Championships are, almost without exception, high responders backed by exceptional genetic talent.

VO2 Max Plateaus Within 2–3 Years of Training

The same graph reveals another key insight: with consistent training, VO2 max tends to level off within approximately 2–3 years — regardless of genetic predisposition.

If you’ve been running for more than three years and your race times are still improving, you’re not imagining it. That ongoing progress is driven by improvements in the two remaining key factors: lactate threshold and running economy.

How Much Can Training Improve Lactate Threshold?

Unlike VO2 max, lactate threshold can keep improving over many years of consistent training.

A well-known example is former elite marathoner Paula Radcliffe, who reportedly improved her lactate threshold by 30% over 10 years of training.

Whether genetics imposes a ceiling on lactate threshold improvement remains an open question — current research has not established a clear answer.

How Much Can Training Improve Running Economy?

Like lactate threshold, running economy can also continue to improve over multiple years of training.

Again using Paula Radcliffe as an example: over 9 years of training, she reportedly improved her running economy by 15%.

Running economy improves primarily through aerobic adaptations accumulated from consistent mileage. Strength training and hill running have also been shown to contribute to gains※3.

A parallel example from cycling: one case study documented an 8% improvement in exercise efficiency, suggesting that refined neuromuscular coordination and movement quality — built gradually over years — are the key drivers of running economy gains.

As with lactate threshold, there is currently no conclusive evidence that genetics limits how much running economy can improve.

Summary

Here’s a quick recap of the key points.

When I first came across these findings, I won’t lie — it stung a little. Talent is real, and it does matter.

But at the same time, I found something genuinely encouraging: years of consistent effort can still take you a very long way.

If you’re stuck in a plateau and wondering whether to keep going, here’s what the science says: keep training consistently, and performance gains will come. Trust the process and push forward.

References

※1 Bassett DR Jr, Howley ET (2000) “Limiting factors for maximum oxygen uptake and determinants of endurance performance” Med Sci Sports Exerc

※2 Bouchard C et al. (1999) “Familial aggregation of VO2max response to exercise training: results from the HERITAGE Family Study” J Appl Physiol

※3 Barnes KR, Kilding AE (2015) “Strategies to improve running economy” Sports Med