On 27 April 2025, Tigst Assefa won the London Marathon in 2:15:50. It was a women-only world record, 26 seconds faster than Peres Jepchirchir’s previous mark. The record itself has already moved on: Assefa returned to London in April 2026 and ran 2:15:41, a time ratified by World Athletics in July.
That makes 2:15:50 a historical record rather than the current one. It does not make the comparison in the headline any less revealing. This is a historical comparison, not medical or training advice, and it needs to be read with the differences between eras in view.
The pace inside 2:15:50
A marathon is 42.195 kilometres. Covering it in 2:15:50 requires an average pace of about 3 minutes 13.2 seconds per kilometre, or 5 minutes 10.8 seconds per mile. The corresponding average speed is 18.64 kilometres per hour.
Those figures can sound abstract, especially when reduced to a pace display. The performance is not one fast kilometre repeated mechanically. Assefa had to hold the average while fatigue accumulated, taking fuel and fluids, following the quickest legal line through turns and responding to a race in which her leading rival, Joyciline Jepkosgei, stayed close deep into the final kilometres. Assefa finally broke clear late and won by almost three minutes.
The World Athletics review of 2025 road running records the result as one of the year’s central marathon performances. Yet its most vivid scale does not come from comparing it with another contemporary woman. It comes from moving it back along the men’s historical progression.
Why the boundary falls in August 1958
World Athletics’ historical account of the men’s marathon progression lists Britain’s Jim Peters running 2:17:39.4 at the Polytechnic Marathon in June 1954. The next listed improvement came from the Soviet Union’s Sergey Popov, who ran 2:15:17.6 at the European Championships in Stockholm on 24 August 1958.
The arithmetic is exact. Assefa’s 2:15:50 is 1 minute 49.4 seconds faster than Peters’s mark, but 32.4 seconds slower than Popov’s. If her 2025 time were placed into that old sequence, it would have displaced Peters and remained the leading performance until Popov crossed the line in Stockholm.
That is what “would have been the men’s world record until August 1958” means. It does not mean Assefa was faster than every man racing in 1958, and it does not invent a head-to-head contest across seven decades. It compares one fully measured time with the recognised sequence of leading men’s marks.
A necessary caveat about the words “world record”
There is a technical wrinkle in the historical language. International governing bodies did not formally recognise road-running world records until 1 January 2004. Earlier leading marathon times were generally described as world bests because course measurement, layout and eligibility were not governed by the same global record system used today.
Calling Peters’s and Popov’s performances world records is common retrospective shorthand, including in record-progression tables. “World best” is the more precise period term. This distinction does not change the comparison between the clock readings, but it prevents a modern ratified record from being treated as administratively identical to a 1950s best.
The conditions were not identical either. Road surfaces, shoes, course certification, timing, drink stations, travel, medical support and the professional structure around elite athletes have all changed. A progression table joins the numbers; it cannot make their sporting environments equivalent.
What the women-only category means
The label can be confusing because 2:15:50 was not the fastest marathon Assefa had run. In Berlin in 2023 she clocked 2:11:53 in a mixed race. World Athletics maintains a separate women-only record category for races in which women do not compete alongside men. The distinction controls for a consequential feature of race structure, including the availability of male runners as pacemakers or moving targets.
It does not imply that one category is a lesser marathon. London’s women’s elite race is a direct competition with its own tactics. In 2025, Assefa had to defeat an exceptionally strong women’s field, not follow a prearranged sequence to a number on the clock. The women-only mark answers a narrower question: how fast has a woman covered a record-eligible marathon in that race setting?
That narrower category is also why the comparison with the 1950s men should be stated carefully. We are matching elapsed time and distance, not claiming identical pacing assistance, competition, weather or course geometry.
Women were denied much of the old starting line
The scale of progress is inseparable from the history of access. For much of the twentieth century, women were discouraged or formally barred from many long-distance events. Kathrine Switzer’s 1967 Boston Marathon became famous partly because an official tried to remove her from the course. The women’s marathon did not join the Olympic programme until Los Angeles in 1984, a milestone in the long campaign for women’s inclusion in elite athletics.
That missing history matters when someone asks why women’s marathon times have advanced so much. The answer is not simply that bodies improved. The organised sport began finding, training, funding and racing far more of the world’s female endurance talent. A larger talent pool met better coaching, more professional opportunities, deeper elite fields, improved nutrition and medical support, legal advances in shoe design, and races built to produce fast competition.
Grete Waitz’s career shows how quickly the frontier began to move once opportunities widened. In 1979 she became the first woman under 2:30, running 2:27:33 in New York, according to the World Athletics account of her career. Assefa’s 2025 London time was 11 minutes 43 seconds faster. The two performances were separated by only 46 years, less than the span of many living memories.
What the comparison can and cannot tell us
The 1958 line is an illuminating benchmark, not a controlled experiment. Peters and Popov raced in the shoes, conditions and sporting economies available to them. Assefa raced as a modern professional on a certified course with contemporary support. There is no responsible way to calculate exactly what any of the three would have run after swapping eras.
Nor does the comparison say that the performance gap between today’s elite women and men has disappeared. It compares a leading woman in 2025 with leading men from the middle of the previous century. Its value is historical: it shows how far a once-restricted side of the sport moved after competition became deeper and opportunity less scarce.
Even the benchmark keeps moving. Assefa’s 2:15:41 in 2026 took another nine seconds from the women-only record. In the same London race, Sabastian Sawe ran 1:59:30, the first sub-two-hour men’s marathon on a record-eligible course. Progress is not a ladder on which one group waits while another climbs.
Where an Earthbound record touches spaceflight
A marathon is a performance under Earth gravity. It does not predict who will adapt best to microgravity, and an elite road-racing programme cannot simply be transferred to a spacecraft. The useful connection is narrower: endurance sport and human spaceflight both care about aerobic capacity, muscular work, fatigue, recovery and the ability to perform when physical reserves are being taxed.
NASA says station crews now average about two hours of exercise each day, using a treadmill, cycle ergometer and resistance device. The treadmill is not there to create marathon fitness. It is part of a countermeasure system intended to limit losses in cardiorespiratory capacity, muscle and bone when normal gravitational loading disappears. As SpaceDaily has previously examined, even extensive exercise does not erase the skeletal challenge of long stays in orbit.
For future Moon and Mars journeys, exercise equipment also competes for mass, volume, power and crew time. Terrestrial endurance research can inform questions about workload and conditioning, but only after it is adapted to a very different environment. That is a real link to space travel, and a limited one.
The larger meaning of the 1958 comparison
Assefa’s 2:15:50 lasted as the record for just under a year because she improved it herself. That does not diminish the time. It sharpens the perspective: a performance that would have led the men’s historical progression for more than four years in the 1950s is already a superseded milestone in women’s running.
The achievement belongs first to Assefa, not to an abstract trend. But the trend matters. Record progressions measure athletes, and they also measure the systems around them: who gets admitted, who can train professionally, who finds serious competition, and whose ability is treated as worth developing.
The most extraordinary part is not the imaginary prospect of Assefa racing men from 1958. It is the real history in which women were given too few chances to establish what their own frontier could be, followed by decades in which that frontier moved farther than the old exclusions allowed anyone to see.