Anecdotal evidence. You are simply on the low end of the bell curve for men.

Endurance is simply how long you can use your muscles before they give out; it's not independent of how much muscle you have. If you are very weak, you will have terrible endurance.

Yes, there are things called fast twitch and slow twitch muscle fibers; the greater proportion of the latter, the better endurance you have. The greater proportion of the former, the faster you go.

There doesn't seem to be evidence of gender difference in the ratio, but Google could have failed me. There is, however, an argued difference along ethnic lines. (East Africans have a much higher slow twitch/fast twitch ratio than other ethnicities.)

Even if there were, though, a marathon is an endurance race. You rely primarily on your slow twitch muscles, except perhaps in the home stretch, if you have anything left. Men win the marathons.

First, I bet in my case neither one of us was really being pushed to the limit. two suburban white kids trying to become slightly less fat? not exactly running for our lives, you know? So it probably has more to do with will and pain tolerance than anything else.

weird, so I thought that the statistics backed up my anecdotes, but at least for pain tolerance, apparently the studies seem to show that men can tolerate more pain... which seems really weird to me. (Have you ever seen a woman give birth? I watched all five of my siblings being born, without any sort of anesthesia. I'm pretty sure that would kill me, or, at least, deter me from having more children.)

So yeah, the first couple pages of google results seem to show that you're right and I'm wrong, though, so eh, whatever. I guess I'm just a wuss.

> Men win the marathons

Among those who run marathons, the top men put in better times than the top women. However, I know _far_ more female marathon runners than men. (OTOH, I know far more male distance cyclists, so I wouldn't jump to any particular conclusions from either data point.)

Really? Are we arguing about this? The males in all mammal species are better at physical tasks. It's called testosterone. It allows you to build more muscle mass. If women take it, they also build more muscle mass. So do female bunny rabbits.

There are other things that go into it, obviously, like body shape. Women are 8 times more likely to tear their anterior cruciate ligament because their wider hips cause them to impact the ground at problematic angles. And boobs are a dead weight.

But yeah, this is something where the biology is very well understood.

Yes, it is very well understood. Muscle mass has little relationship to endurance.

In endurance events (real endurance, not wimpy things like 2-3 hour marathons) women are highly competitive with men, and there is some evidence they have an advantage.

For example, in the 235km Badwater Ultramarathon, women consistently finish top 5, despite representing only 5-10% of the field.

Long distance swimming is even worse for men. Shelly Taylor-Smith has held the record for the 48km Manhattan Island swim since 1995. Women are within 28 minutes of the outright English Channel swim crossing record (6:57 vs 7:25), and based on this older swim time list, women have 9 out of the top 20 times: http://www.channelswimming.com/solo-time-HTML.htm

I'm going to resort to quoting papers to you:

"When performing certain isometric exercises, the endurance of women is almost twice that of men performing the same exercise, according to results presented at a meeting of international scientists. Both sexes performed the exercises at the same percentage of their maximum strength. The study, conducted at the University of Colorado in the US, confirmed that women outlasted men by an average of 75 per cent and, importantly, showed that the reason women had longer endurance times was not due to differences in the motivation levels between men and women, or within the nervous system, but due to differences within muscle." http://www.mydr.com.au/sports-fitness/women-beat-men-on-musc...

"The negative slope and the X-axis intercept of this equation at 66 km supports the hypothesis that women ultramarathon runners have greater fatigue resistance than do equally trained men whose performances are superior up to the marathon distance." http://www.ncbi.nlm.nih.gov/pubmed/9044230

Muscle mass seems fairly clearly distinct from endurance, given that most distance athletes aren't particularly bulky. And I'm highly skeptical that "The males in all mammal species are better at physical tasks". Among humans, I think it's generally accepted that women have better fine-motor control (for example, women were hired to assemble early core memories for this reason). Another well-known counterexample is lions: "Lionesses do the majority of the hunting for their pride, being smaller, swifter and more agile than the males" (http://en.wikipedia.org/wiki/Lion)