An analysis of world race records reveals how gender, age, ethnicity and distance combine to shape endurance running, from the 5km sprint to marathon dominance.
Study: The association between ethnicity, sex, age and running performance in endurance runners: an empirical analysis of global multi-distance race data from 1999 to 2024. Image credit: kovop / Shutterstock
In a recent study published in the journal Scientific Reportsa team of researchers examined how ethnicity, gender and age are associated with running performance in 5km, 10km, half marathon and marathon events around the world from 1999 to 2024.
Background
Why do Kenyan and Ethiopian runners dominate marathons, while there is plenty of participation from Japan or the United States? Millions of people enjoy endurance running and their performance depends on factors such as age, gender, training culture and geographic location.
A review of the existing literature reveals age-related differences in peak athletic performance and suggests that East African runners outperform other competitors in distance events in ways that may reflect unique physiological, environmental, and cultural advantages. However, limited research has compared these patterns across multiple race distances simultaneously. More studies are therefore needed to better understand how demographic factors interact in endurance events.
About the study
The researchers analyzed publicly available data from official records maintained by World Athletics (formerly the International Association of Athletics Federations) and the Road Racing Statistics Association.
The data set consisted of eligible records reported for the time period 1999–2024 for 5 km, 10 km, half marathon and marathon races, with 5 km data supplemented by ARRS because track and field world records were only available from 2018 to 2024.
After filtering and removing missing data, a final data set of 152,943 runner records was created, including runners from 203 countries, regions or representative groups, with 91,182 men and 61,761 women.
Performance cut-off points were established in order to maintain consistency when comparing across races. Runners who did not finish, were disqualified from the finish, did not start or had incomplete records were excluded from the analysis. The neutral groups (the refugee group and the neutral athlete group) were also removed to avoid statistical bias.
The researchers conducted mixed-effects modeling and multiple linear regression analyzes of the relationships between ethnicity, age, gender, and an athlete’s running performance. A three-way analysis of variance (ANOVA) was used to examine the interaction between ethnicity and gender on running performance, while adjusting for year of competition.
The researchers used t tests to compare men and women and Pearson correlation coefficients to assess relationships between age and race outcomes. Statistical significance was set at a probability value below 0.05. As this was an observational analysis of public racing records, the findings identify correlations rather than causal effects.
The ratio of nationalities of runners by race distance and gender. Countries with less than 1% are included in “Others”.
Study results
The results showed a consistent difference between gender, ethnicity, age and distance race experience in endurance running performance. In all four race categories, men consistently outperformed women.
Average running speed across all events was faster for men than for women. only the 5 km distance had an average combined speed of more than 20 km/h. Male runners were significantly faster than female runners at all distance levels. However, this performance gap became particularly pronounced at half-marathon and marathon distances.
Participation patterns also varied by country and distance. In the 5km event, runners from the United States and Japan formed the largest groups of participants, followed by Kenya, France and Australia. In the 10km race, France and Kenya contributed many participants, while Japan and Kenya were prominent in the half marathon and marathon.
Kenyan and Ethiopian runners consistently rank among the top performers in all endurance events, confirming East Africa’s continued influence on distance running.
Bahraini athletes also demonstrated excellent average race times in various events, although findings based on nationality should be interpreted cautiously as some countries may include naturalized athletes.
Age standards changed as race distances increased. In the 5km race, men and women had a similar average age, around 25 years. However, women were progressively longer than men in the 10km, half marathon and marathon races. In the study, marathon runners were the largest group, mostly aged 25-35. It was also observed that younger athletes were more common in shorter races, while older runners were more common in longer endurance races.
Running performance differed significantly by ethnicity. Runners from East Africa, particularly Kenya, Ethiopia, Uganda, and Eritrea, consistently recorded strong performances, especially in longer distance races, which may reflect altitude adaptation, strong running culture, genetics, and long-standing training systems. In contrast, Japan’s success was linked to organized corporate operating groups and the country’s deep-rooted ‘Ekiden’ relay culture.
There were significant declines in race participation across all distances between 2020 and 2022 due to the COVID-19 pandemic, which resulted in the cancellation of races and the implementation of public health restrictions in all countries. However, participation subsequently showed a recovery, particularly in longer distance races.
The study found strong links between age and race performance in half marathons and marathons (especially among women). There were weak associations between age and race performance in shorter events such as 5 km. Interestingly, female runners in the 5 km event showed a negative relationship between age and race time, suggesting that slightly older women in smaller age groups often achieved faster times.
conclusions
The study shows that endurance running performance is shaped by a complex interplay of ethnicity, gender, age and race distance. East African athletes, particularly from Kenya and Ethiopia, remained particularly prominent in long-distance events, while Japan and the United States contributed large numbers of participants in all events. Men consistently achieved faster race times, while women competing in longer events were generally older.
The study data show that performance patterns differed by race distance and demographic background. These results are important for athletes, coaches and sports organizations as they can be used to help develop training programs, identify talent and understand the evolving global endurance running culture.
