Battle of the Sexes
by Pete Pfitzinger, M.S.
In n the weeks since Naoko Takahashi and Catherine Ndereba broke the world best time for the women’s marathon, many comparisons have been made between the men’s and women’s marathon records. As in 1983, when Joan Benoit Samuelson slashed the women’s best by running 2:22:43 at Boston, there is talk of the best women eventually beating the best men. The case is based on analysis of trends in the record books and physiological differences between the sexes. Let’s see if the argument stacks up.
In 1985, the women’s marathon world best was Ingrid Kristiansen’s 2:21:06, and the men’s mark was Carlos Lopes’s 2:07:12. Today, the women’s record is 2:18:47, and the men’s mark is 2:05:42. The difference between the men’s and women’s world best times, therefore, was 13 minutes and 54 seconds in 1985 and is 13 minutes and 5 seconds today. This is hardly a startling change. In fact, given the relative newness and increasing depth of women’s marathoning, one might have expected the gap to narrow more over the past 16 years than it has. Of course, although no woman is likely to run a 2:05 marathon, the best women runners already beat the hell out of all but the very best men marathoners.
Another favorite pastime of the historians among us is comparing the men’s and women’s world records at various distances, with the assertion that the gender gap decreases on a percentage basis as the distance gets longer. In actuality, the remarkable thing about the percentage difference between men’s and women’s best performances from 100 meters through the marathon is the consistency of the gap, which is roughly 10% across the range of distances. Fair comparisons may be confounded by the likelihood that some of the world records were set with the aid of performance enhancing drugs. There is, however, no evident trend in the percent gap between men’s and women’s best performances over the range of Olympic running distances.
An additional argument that has re-emerged in the aftermath of two women running sub 2:20, is that women’s higher essential fat stores and/or higher ability to use fat as fuel may provide an advantage in long distance events. Well, higher fat stores may be an advantage for buoyancy and heat retention in swimming the English Channel, but if it was an advantage in the marathon, then Naoko and Catherine should put on some weight. For a runner, higher fat stores would only be an advantage in an event in which she or he is at risk of running out of fat. Considering that a pound of fat provides 3,500 kilocalories of energy and that roughly 100 kilocalories of energy are burned per mile of running, no one is going to run out of fat during a marathon. Quite simply, women’s higher essential fat stores are a disadvantage for marathon running because the extra weight must be carried for 26.2 miles.
Recent studies have provided evidence that women can utilize slightly more fat for fuel during endurance exercise than men, which may be related to women’s higher estrogen levels. The ability to use fat is an advantage for the marathon because the body can only store about 2,000 to 2,500 kilocalories of glycogen (carbohydrate), so a contribution from fat is required in covering 26.2 miles. Fortunately, one of the major adaptations of marathon training for both sexes is an increased ability to utilize fat during exercise. Any highly trained marathoner who does a reasonable job of carbohydrate loading prior to the marathon is not likely to run out of glycogen when running 26.2 miles. Taking a carbohydrate drink during the marathon provides a further cushion against glycogen depletion, so higher fat utilization is not necessary for an elite marathoner (although it may be useful for the less well-trained).
The marathon is simply not long enough to nullify the physiological advantages that men have in testosterone level, maximal oxygen consumption, and hemoglobin level. Given that over 99% of the energy used in the marathon is produced aerobically, women’s lower hemoglobin level (which mean women can transport less oxygen per unit of blood) is a distinct disadvantage.
Back in 1983, I remember watching Joan Benoit Samuelson with admiration as the first woman runner I had ever seen train as hard as the men. Ingrid Kristiansen was the only woman in the world at that time with similar talent and a similar willingness to absorb hard work. Today, perhaps 15 Kenyan, Ethiopian and Japanese women have reached that level of training, and a few such as Takahashi and Ndereba are attempting to take training a step further. Takahashi trains over 130 miles per week during her marathon build-ups, often at high altitude, and has had the occasional training day of over 40 miles.
Will the gap between men and women’s marathon world best times get smaller? Probably, but not by much. Even with the best 10,000 meter runners such as Paul Tergat and Haile Gebrselassie now turning to the marathon, the record is unlikely to drop by more than another minute or so in the next decade. While only a handful of women have threatened the women’s mark to date, it is the increasing depth of women’s distance running worldwide, particularly from the strong African nations, that will likely see the women’s mark fall by another 2 to 3 minutes in the next 10 years.