What role do genetics play in athletic performance across different ethnic groups?
Executive summary
Genetics contributes substantially to athletic traits — estimates of heritability range widely but commonly center around roughly half of the variance in performance — yet no single gene or “speed gene” explains group differences and genetics cannot reliably predict individual success [1] [2] [3]. The scientific consensus is that athletic performance is a complex, polygenic trait shaped by hundreds of variants interacting with training, nutrition, socioeconomic context, geography and culture, and that claims tying ethnicity to innate superiority are both scientifically weak and socially fraught [4] [5] [6].
1. Genetics matter, quantitatively but not deterministically
Twin, family and genomic studies show that genetic factors explain a substantial share of differences in traits relevant to sport — published estimates of heritability range broadly (often cited as 30–80% for various traits and about ~50% overall for performance), indicating genetics is a major contributor but not a fate determiner [4] [1] [2]. At the molecular level researchers have identified many polymorphisms — on the order of dozens to hundreds — associated with endurance, power or injury risk, but most variants have small effects and few have been robustly replicated across populations [5] [7] [8].
2. Polygenic architecture and the limits of single‑gene narratives
Decades of work on candidate variants such as ACE I/D and ACTN3 R577X illustrate the pattern: some studies find associations with endurance or power traits, others do not, and results often differ by sport, sex, age and ethnicity — undermining the idea of a universal “athletic gene” [9] [10] [8]. Meta‑analyses and recent large studies conclude that performance is polygenic and context‑dependent, making simple genomic predictions of elite status premature and unreliable [1] [5].
3. Ethnicity, geography and the danger of overinterpretation
Observed concentration of elite athletes from particular regions or ethnic groups — for example East African dominance in distance running — has prompted genetic hypotheses, but careful reviews find no single explanatory genotype, emphasize mixed ancestry and point to phenotype emergence from many factors including altitude, diet, training culture and selection bias in who enters elite sport [11] [12]. Historical and social variables — access to coaching, economic drivers, cultural emphasis and talent pipelines — routinely confound population comparisons, so attributing group differences primarily to genes is scientifically precarious [6] [13].
4. Environment, epigenetics and the “trainability” factor
The same genomic background can produce different outcomes depending on environment: training methods, nutrition, recovery, injury prevention, and even birthplace effects influence who reaches the top, while epigenetic and gene–environment interactions modulate physiological responses and “trainability” [4] [5] [8]. Studies document that genetically influenced traits like muscle fiber composition or aerobic capacity interact with lifestyle and coaching to shape performance, meaning environment often amplifies or suppresses genetic potential [7].
5. Science, ethics and commercial hype
Researchers repeatedly warn against using current genetic knowledge to select or pigeonhole athletes — the evidence base is heterogeneous, replication is limited, and predictive power at the individual level is low — yet commercial genetic tests market talent prediction to parents and teams, raising ethical concerns about discrimination and false promises [2] [1] [9]. Critics from both science and sport communities have pushed back against simplistic racialized narratives, arguing that emphasizing genetic determinism can obscure structural inequalities and encourage misuse of genomic data [3] [6].
6. Where the research still needs to go
The field is moving toward larger, multiethnic genome‑wide studies and integration of transcriptomics, metabolomics and longitudinal training data to better model how many small variants combine with environment to produce elite performance, but authors stress that current knowledge is not yet ready for societal application such as talent screening or personalized selection [5] [1] [2]. Until replication, clearer effect sizes across diverse populations, and robust ethical frameworks exist, genetics should be treated as one piece of a multifactorial puzzle rather than a verdict on individuals or groups [7] [12].