It takes getting used to, seeing young women run long distances, gasping and gagging and staggering around and going down on all fours at the finish line, pink foreheads in the mud,” began an article in Sports Illustrated in 1966 about the National AAU Women’s Cross-country Championship. “But they are young women, all right, make no mistake. The shaved legs, the singlets that actually do a service, all that symmetry, that fragrant hair.” One athlete’s coach, “a practical man, says it is good that she is trimmer, too, because she is going to be a woman much longer than she is going to be a runner.”

So what exactly were the “long distances” writer John Underwood was referring to? A mile and a half. For even the most recreational of racers set to compete in this Sunday’s 2011 ING New York City Marathon, that would barely even constitute a warm-up.

If seeing athletes later described as “pretty little dedicated things” compete in that race took some getting used to, imagine the reaction a few months earlier in 1966, when, to quote another SI piece, a “shapely blonde housewife” named Roberta “Bobbi” Gibb Bingay snuck onto the course of the venerated Boston Marathon and not only finished the whole damn thing, but did so ahead of nearly 70 percent of the field. Not officially, of course. “Mrs. Bingay did not run in the Boston Marathon,” SI quoted the event’s organizer as asserting. “She merely covered the same route as the official race while it was in progress.”

The next year, a Syracuse student named Kathrine Switzer officially registered for Boston by filling out her entrant form as “K.V. Switzer.” When race officials realized what was going on, they tried to tackle her, a move they later defended as a valiant attempt to enforce AAU rules that banned women — for their own good, of course — from competing in any race of more than those 1.5 miles.

I was born in 1983, something of a Title IX-driven sweet spot for a budding female athlete: While my fifth grade travel soccer team was the first all-girls team in our township, just about every other road had already been paved by women that came before, leaving girls my age to concentrate on breaking sweats, not breaking barriers. Which is why it was so surprising to me when I learned that I happen to be older than the women’s marathon in the Olympics, which didn’t become an event until 1984. It took that long?

What made this even more startling is the fact that these days, there may be no sport more democratic than distance running. Of all the tons of e-mails that come my way every fall from friends fund-raising for their marathon efforts (the surest way to make the race is to do so via charity, as otherwise you’re at the whims of the lottery system), probably more than half come from my girlfriends, and when I’ve stood on First Avenue in Manhattan tracking my friends with newfangled iPhone apps so that I can briefly shout their name as they gazelle or straggle by, the paces between the men and women are largely indistinguishable.

But those are the hoi polloi, the people jogging alongside guys in chicken suits or Oprah. Surely at the elite end, there exists a much wider discrepancy, whether by function of biology or of being held out from distance running for so long. Right? Well, increasingly, not as much as one might think.

Grantland’s ace infographer Alex Morrison was looking at the data for the top 100 finishes since the New York City Marathon was first held in 1970 (a low-key affair by today’s standards, given that the male winner, Norman Higgins, had come in from Connecticut to run a 5K in the Bronx, entered the marathon on a whim, and won by over ten minutes, still the men’s race’s largest margin of victory). What Morrison noticed was that, while the top women’s times have not necessarily changed substantially over the last several decades, the concentration of runners hovering around them has largely grown.

Over 47,000 people are expected to participate in this year’s New York City Marathon, and that is only a fraction of the number that wanted in: While the event grows yearly, it still shuts tens of thousands out each year. In fact, it has become so large that race organizers recently had to change their policies, grandfathering out or making stricter old rules around guaranteed entry. (The Boston Marathon also recently lowered its already stringent qualifying times.)

As more and more people have “caught the fever,” even once-esoteric schools of running doctrine have grown more mainstream: Witness this weekend’s New York Times Magazine story about the virtues of shoeless running by Christopher McDougall, whose book Born To Run: A Hidden Tribe, Super Athletes, and the Greatest Race the World Has Never Seen has become something of a manifesto to hard-core barefoot (or barely-covered-foot) enthusiasts.

While Born to Run is most widely cited and well known for its treatment of that topic, it also devotes plenty of space to another evolution-based theory that is just as grand: as distances increase, the gap between male and female performance not only disappears, it can reverse. “No woman ranked in the top fifty in the world in the mile (the female world record for the mile, 4:12, was achieved a century ago by men and rather routinely now by high school boys),” McDougall writes. “A woman might sneak into the top twenty in the marathon (in 2003, Paula Radcliffe’s world-best 2:15:25 was just ten minutes off Paul Tergat’s 2:04:55 men’s record). But in ultras [ultramarathons, which can refer to races ranging from 50 kilometers to 100 miles], women were taking home the hardware.”

Runner’s World editor-at-large Amby Burfoot, who won the Boston Marathon in 1968, disputes this notion. “That’s been a hot topic that’s been out there for a millennia and has not been found to be true,” he said, adding that the gap between men’s and women’s runners hovers around 10-11 percent in most races. (“You can bet on it and make a lot of money,” he advised.) Still, he said that the sheer numbers of elite female entrants have helped account for more women cracking the top 100 in an event like New York. “Since there are more women and they’re getting faster, there are more women at the top,” he said. “Obviously women’s running is exploding on our front.”

New York organizers estimate that 38 percent of marathon entrants this year will be women, up from 32 percent in the early aughts and less than 20 percent a decade before that. Increased participation is not just happening in the marathon. In races of all sorts of lengths put on by the New York Road Runners (the organizing body that manages the marathon), more women than men are competing in the 20-24, 25-29, and 30-34 age groups.

On the elite level, there has been an increase in the number of competitors from two notable sources: traditional long-distance powerhouse nations like Kenya and Ethiopia, whose training programs have grown increasingly well organized and visible to young women — and, particularly domestically — the pool of female runners moving up to the marathon from middle distances.

Rabbit, Run While she won’t be running this weekend in New York, Paula Radcliffe, one of the marathon’s most recognizable names, has already had a headline-filled fall. The 38-year-old Radcliffe ran her first marathon since 2009, finishing the Berlin race in late September with a time good enough to qualify her for the 2012 Olympics in her home country of England and third place overall. She admitted slight disappointment with her showing, but it likely paled compared with the news she got a few weeks later: The IAAF ruled that her 2003 world-record marathon time of 2:15:25 was no longer legit. The reason? She had set it during a mixed race and thus used a male pace-setter, known in industry parlance as a “rabbit,” to help achieve the goal. Rabbits are neither illegal nor uncommon; a huge number of elite runners will employ one or more. But in a men’s-only world record attempt, for example, the rabbits always drop back at some point — if they could run the whole race at world-record speeds, they’d be the ones with their names in the books. In contrast, the IAAF argued, male rabbits who help pace a woman are able to run the entirety of the race at a world-record speed. Radcliffe has appealed the decision, while Nike has used it as fodder for a new marketing campaign called “HISTORY STANDS.” For the time being, the official world record now stands at 2:17:42 — only the third-best time that a woman so fast she was once described by Running Times as being “an outlier of unfathomable magnitude” has recorded.

American Kara Goucher is among the more notable of the latter type. After running World “A” Standard times in track events including 1,500 and 5,000-meter distances, Goucher ran a half marathon in 2007 that was the first race she’d ever competed in over 10,000 meters — and won. She qualified for the 2008 Olympics in the 5,000 and 10,000 meter races, finishing ninth and 10th respectively, and three months later made a stunning NYC Marathon debut, finishing third among women and 34th overall. Her time of 2:25:53 was both the fastest-ever marathon debut, and the fastest NYC time, recorded by an American woman.

“My coach really wanted me to try the marathon,” she told the New York Times. “I wasn’t convinced. The marathon is such a challenge. Just because you can run a 10K well doesn’t mean it’s going to transfer to the marathon. I kind of fought it I was terrified of the distance and the pain.”

Her training partner, Shalane Flanagan, who earned the bronze medal in the 10,000m in Beijing, made her own marathon debut in 2010 and finished second, the highest finish for a US woman in 20 years.

“It is true that the marathon is the flash point for a lot of women runners,” Burfoot said, “Meaning that women who would have stayed on the track in the past in the 5 or 10K are now moving up to the marathon and proving they’re very talented and very fast.”

It’s typical for runners to go up in distance as they move through the ranks of, say, the collegiate level — their natural speed, combined with the increased endurance that can come from more focused training, makes it a worthy strategy. “A lot of people try to resist that for some reason,” said Catha Mullen, who ran the mile in high school and moved up to the 5K at Princeton. “I would never have imagined running a marathon as a youngster, or even in college.” She finished 11th in New York in 2009 and is now training for the upcoming US Olympic Qualifiers in the event.

What’s notable about runners like Goucher and Flanagan, in particular, is how dominant and flat-out athletic they are. Unlike some marathoners who got pushed up in distance because they were middling in strength and speed, those two, among others, are different: They’re moving up almost despite being so freaking fast.

Burfoot cautioned that looking solely at the women’s share of top 100 overall finishes can be misleading — “it’s not a statistic we’d think of as having a lot of meaning,” he warned, noting that every marathon is so unique, comprising such ever-changing fields of entrants, that it’s not quite an apples-to-apples comparison. (The volatility between 2009 and 2010, for example, is partly a function of the fact that the USA Marathon Championships were hosted by New York those years for men and women, respectively.)

This year will have its own quirks: the US Olympic Qualifiers are being held this January in Houston, meaning most of the United States’ top distance runners will be resting rather than running through the five boroughs. Top runners like Kenya’s Mary Keitany, Ethiopia’s Buzunesh Deba, and New Zealand’s Kim Smith will all be competing, however. And the US will still have its own entrants, like Jen Rhines, a three-time Olympian in the 10,000m, the marathon, and the 5,000 who is returning after a five-year break from marathons, and Lauren Fleshman, another middle-distance standout who will be competing in the longer distance for the first time.

Fleshman has her worries. “I’m confident I can handle pain,” she told espnW’s Sarah Lorge Butler. “I’m confident I can handle the length of time. But my biggest fears come from things like, what happens if I have to, like, go poop? I mean, what do you do? Really. Do you stop or do you just do it?”

Statistics, world records, and “outliers of unfathomable magnitude” aside, it’s things like this that show how far women’s running has really come. Every pink dot on that chart — and all the ones found beyond the top 100 finishers — represents a new era of “pink forehead in the mud,” women running fair and square in a race from which their own mothers were expressly banned. Less than half a century ago, coverage of the sport in major magazines included descriptions of “fragrant hair” — imagine how they’d react to this new kickass generation of fast and feisty ladies.

Katie Baker is a staff writer for Grantland.

Previously from Katie Baker:

Benching Ovechkin

The Horrible Habs

Coming to Grips With the Winter Classic

The Endless Battle Over Hockey Fights

Week 1 in the NHL

How to Pick an NHL Team

Coldhearted: Our Weekly Hockey Column Debuts

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