Trainability of Endurance Talent: The HERITAGE Study, Responder Differences, and a Pragmatic Mindset

Same Training, Wildly Different Progress

Coaches and athletes have all observed it: on the same training plan, some people see a huge jump in VO2max, while others barely move. This isn’t a difference in effort or execution—training response itself shows significant individual variation, and it’s largely determined by genetics. Understanding this isn’t an excuse to give up; it’s about designing expectations, metrics, and strategies that fit the individual, avoiding a one-size-fits-all template and misattributing the causes.

Key Findings from the HERITAGE Study

The large family-based training study (HERITAGE Family Study) had family members perform a standardized endurance training program and found:

• The magnitude of VO2max training response varies greatly between individuals: on the same plan, some improve a lot, while others barely respond (low responders); the heritability of this response magnitude is ~50%, and it clusters within families (responsiveness is heritable).
• Baseline VO2max and training response magnitude are different heritable traits—being naturally gifted doesn’t mean you’ll improve more from training, and vice versa.

“Non-Responders” Are Often “Not Matched to the Stimulus”

Important correction: subsequent research shows that many who “don’t respond” to one training plan can still improve when the training stimulus is changed (higher intensity/volume/type)—“low response” is often relative to a specific stimulus, not a lack of response to all training. This supports “individually adjusting the stimulus” rather than prematurely concluding “no talent.” Meanwhile, performance is multidimensional: low VO2max responders may still have substantial room for improvement in lactate threshold, economy, buffering capacity, capillarization, and strength (see the articles on lactate threshold, economy, buffering, and capillarization).

A Pragmatic Mindset and Strategies

• Individualize expectations: set expectations based on your own historical trajectory rather than “average response curves” or others’ improvement rates (related to the articles on goal setting and social comparison); don’t deny your effort or recklessly ramp up volume just because you improve less than others.
• If the stimulus isn’t working, change it: when progress stalls on a plan, first consider “whether the stimulus type/intensity/periodization model needs to change” (see the articles on interval design and periodization), rather than simply adding volume or concluding you lack talent—overtraining from excessive volume is the worst outcome (see the article on overtraining).
• Develop multiple dimensions: when VO2max gains are limited, shift resources toward highly trainable areas like threshold fraction, exercise economy, strength, and pacing/mental skills—among elites, VO2max differences are small, and races are often decided in these trainable areas (see the articles on economy, strength, pacing, and self-talk).
• The role of genetic testing: current consumer-grade “sports genetic tests” have limited predictive power for personalized training and should not be used as a basis for talent selection or giving up; the most reliable basis for individualization remains monitoring actual responses to training (HRV/sRPE/performance/subjective feel, see related articles)—that is, “use your body’s feedback to infer the right stimulus.”

For Athletes and Coaches

Talent sets the potential range and the starting line, but: training determines how far you can go within that range; although responsiveness has a genetic component, “switching to the right stimulus” can often unlock what seemed like a ceiling; and performance is multidimensional—being limited in one dimension doesn’t mean you’re limited overall. Focusing on “finding the stimulus that works for you and executing it consistently for years” is far more productive than obsessing over talent.

The same plan—some fly, some don’t budge. That’s the hand genetics dealt you, not a lack of effort. But the game isn’t played with only the VO2max card—switch the stimulus, attack threshold and economy, turn mental skills and pacing into real strengths, and many “low responders” can still be very strong. Talent draws the lines; training determines how far you go within them.

Related Reading

• Individual Differences in Training Adaptation: Genetic Factors in Performance Changes Under the Same Training Plan
• Individual Variability in Endurance Training: A Genetic Analysis of the “Non-Responder” Phenomenon
• Exercise and Genes: The Interplay of Innate Talent and Acquired Training—The Science and Myths of Heritability, Responders, and Genetic Testing
• Precision Sports Medicine: Personalized Training Programs Guided by Genomics