Female equivalent of the Two-Hour Marathon
[Article by Tait Hearps of Sweat Elite]
On a cool Viennese morning, October 12, 2019, Eliud Kipchoge did what was once almost unimaginable, running a sub-2-hour marathon. The Ineos 1:59 challenge was a staged race that was not record eligible, but it still provided a paradigm shift in the sport, opening a door to a new realm of possibilities. The sub-2 is such a heralded landmark in the sport, however this is a benchmark which, at this stage, is only conceivably achievable by a male.
The following day, on the other side of the Atlantic, Kipchoge’s compatriot Brigid Kosgei shattered the long-standing female world record. Kosgei demolished the field at the Chicago Marathon, finishing in 2:14:04 and besting, by over a minute, the standard set by Paula Radcliffe back in 2003.
There’s no getting around the fact that elite males finish marathons significantly faster than their female counterparts. But this begs the question, what is the equivalent of the sub-two-hour marathon for females? This is a question which has been examined by some of the brightest minds in sports science, and the postulated theories provide some interesting further questions, at this stage the answers are far from conclusive.
Doctor Michael Joyner M.D. is a renowned scientist studying the limits of human physiology, he is well-known in running circles for his paper in the Journal of Applied Physiology, back in 1991, that speculated that the “hypothetical best subject” could run a marathon in 1:57:58. This was at a time when the current world record was 2:06:50, set by Belayneh Dinsamo in the 1988 Rotterdam Marathon. The variables that went into formulating this prediction were maximal oxygen uptake (VO2 max), lactate threshold (as a percentage of VO2 max) and running economy. For those interested, the hypothetical values he used were “a VO2 max of 84 ml kg-1 min-1, a lactate threshold of 85% of VO2 max, and exceptional running economy.” His paper at the time left a lot of people confused and very sceptical, but with Kipchoge’s recent performances closing in on this hypothesised ideal performance (albeit with a long way yet to go), Joyner’s prediction no longer seems so far-fetched.
Why am I talking about Michael Joyner’s predictions of the fastest conceivable marathon time? Well, Joyner and a number of other researchers have published a paper (again in the Journal of Applied Physiology) on the female equivalent of the two-hour marathon, addressing “physiological, historical, and social factors that contribute to current and past sex differences in marathon performance.”
This paper was published in 2015, when the world records stood as follows:
Men: Dennis Kimetto, Kenya – 2:02:57 (2014 Berlin Marathon)
Women: Paula Radcliffe, UK – 2:15:25 (2003 London Marathon)
Their initial approach to establishing the equivalent mark is to determine the difference in marathon performance by elite athletes of each gender in terms of a percentage. The difference between these two records was approximately 10%, meaning that the equivalent to a two-hour marathon for women would be 120 minutes plus 10%, 2:12:00. However, when analysing the top marathon times (at the time of writing their study), it appeared that the difference between men and women was more significant than 10%, coming in at closer to 12-13%. Interestingly online predictors such as the Mercier Score suggest that the two-hour equivalent sits at 2:15:34, and this had already been achieved by Radcliffe (and subsequently smashed by Kosgei).
At the time Paula had the top three marathon performances in history, and they were significant improvements on the next fastest times (with the 4th fastest time being 2:18:20). There is a precipitous drop-off in running velocity (expressed as a percentage of the velocity set by the world record) when looking at the women’s times (Graph A below), whereas the men’s results show a much more gradual decline. However, when excluding the three outlier data points (set by Radcliffe) and starting with the 4th fastest time (white circles rather than the white triangles in Graph A below), the rate of decline is much more similar to that seen in men’s times. Around the 50th data point the rate of decline again increases relative to the men.
(Credit: Hunter SK, Joyner MJ, Jones AM, 2015)
Based on analysis of this data the researchers concluded the following:
Radcliffe’s times were exceptional (having the three fastest times and such a long-standing record).
There is less depth in the female field, demonstrated by the less gradual decline in performance right through the top 200 times. The top men’s times were predominantly achieved over the preceding 7 years (2007-2014), whereas women’s times were much more spread out over the preceding 15 or so years (with one as far back as 1985 – 30 years prior to the article being published).
And how has this changed in the intervening years? Well Kosgei’s time, which bested Radcliffe’s by over a minute, means that there is another “outlier” at the top of the chart. The relative lack of depth in the women’s field persists (when looking at top times and relative rates of decline in velocity). The top ten times by men all being run in the last 5 years (7 of the fastest marathoners have run their times in the last two years), whereas there are still times from 2001 and 2003 in the women’s top ten list.
As we said earlier, there are multiple physiological variables that determine how quickly the marathon can be run, and these differ somewhat between sexes. According to the paper in question, “in highly trained men and women, running economy is similar and does not appear to explain sex differences in performance either. In general, in equally trained men and women, the sex difference in performance is mostly dictated by men’s larger V̇o2max because men have a larger heart size, larger muscle mass, less body fat, greater haemoglobin concentration, and consequently a higher V̇o2max than women.” VO2 max is quoted as being, on average, 10-14% higher in elite male athletes. Other factors that could contribute to the difference between sexes include substrate utilization, muscle fatigability, pacing, and competitiveness.
Other cultural factors play into the difference in the marathon performances seen between men and women. Women did not compete in the marathon at World Championships until Helsinki 1983 and the Olympics in Los Angeles 1984. Prior to the 1970s women were banned from competing in the marathon as it was thought their bodies could not cope with the physical demands of the distance, which has obviously been shown to be completely fanciful (especially now given the successes of female athletes in ultramarathons – see this article on Courtney Dawaulter to have your mind blown). Furthermore, globalisation of women’s running was more delayed than for men, as seen by the emergence of East African dominance coming later for women compared with men.
In the conclusion of the paper, the authors claimed that the evidence suggests that the female equivalent of the two-hour marathon had already been achieved by Paula and that her world record would potentially stand for many years, “until a woman, possibly an East African, who possesses superior running economy and high critical velocity is afforded the opportunity to compete.” Other researchers have made commentaries on this paper suggesting different theories and ways to determine the equivalent time.
One glaringly obvious problem with this whole idea is that the two-hour mark is an arbitrary benchmark, it just happens to fit so snugly into the sexagesimal (base 60) horological system created by the Sumerians and used by us to this day. Unfortunately, the physiological variables that affect human performance don’t take heed of this system. Another problem with trying to find the point of equivalence is that there is a paucity of data on the physiological limitations and mechanisms of fatigability and performance in women. This results partially due to biases in which predominantly males volunteer or are selected for participation in studies in exercise science, and the presumption that both sexes respond similarly to exercise.
Unequivocally concluding whether or not Brigid’s (and/or Paula’s) efforts are the female equivalent of the sub-two hour marathon seems to be unfeasible with the current state of sport science and the inherent variability in individual physiology. Irrespective of this, Brigid’s performance also marks a giant leap forward for women in the marathon, and hints that more significant progress could be on the horizon. One very conspicuous feature shared by the two historical performances on that fateful weekend in October is the use of a variant of Nike’s Vaporfly shoe. This is a contentious issue and we will save that discussion for another article.
Brigid’s comments in the post-race press conference further shed light on her views on the future of women’s marathon running: “If a lady can prepare good and they have no injury… the can reduce to 2:12 or one minute to 2:13.” While she stopped short of implying that she herself might achieve those times herself, she made it apparent that her main aim is to get even faster. “I’m still focussing to reduce my time again – if it’s possible.” Given that the mother of two is only twenty-five and has had such consistent improvements in her times over the last few years, it seems likely that she will continue to take time off the new benchmark she has set. Heading into the Olympics next year Kosgei is definitely someone to watch!
In conclusion, given the variability in physiology between the two sexes it is not feasible to exactly calculate an equivalent for the two-hour marathon for females. However, with the recent improvements we have seen in performance, technology, competitive opportunities afforded to women, and increasing depth in the female fields of major marathons, it appears likely we will see continued improvements in the discipline.
