Any discussion about pacing in distance running is bound to ruffle a few feathers, so let’s start this off with a statement on which we can all agree: Steve Prefontaine was a goddamn legend.

There are few, if any, runners that have attainted status in the sport’s collective psyche quite like Pre. But whether we attribute this universal renown to his undeniable dominance in American collegiate running, or to the ways in which his life so closely interwove itself with the the early lore of Nike, the core of his legend doubtless lies in the way that Pre ran.

Pre was a front-runner, and a relentless one at that. His racing style eschewed tactical running, opting instead to go out aggressively, from the gun, stubbornly refusing to relinquish the lead. “No one will ever win a 5,000 metre by running an easy two miles,” he was quoted as saying. “Not against me.”

What makes Pre remarkable isn’t the fact of his front-running – front-runners are a dime a dozen in this sport – but the fact that he was a front-runner who was actually good. More than good, really. He could talk a big game, run a balls-out race ostensibly devoid of strategy, and still manage to win by a wide margin. There was a romance, and a purity, to his approach to distance running.

It’s easy to love Prefontaine.

But the fact is, most runners are not Prefontaine. Most runners, regardless of talent, grit, and preparation, run better when they run tactical races. They hang in the pack. They respond to the movements of their fellow runners. They draft off of each other, expending a carefully calculated level of effort, and wait patiently for the ideal moment to throw in a surge and drop the competition.

In short, most runners run best with the aid of pacers.

Pacing is a controversial practice in distance running. Heavy-hitters in the sport, individuals and institutions alike, have by turns encouraged and denounced the employment of elite pacers in road racing. This debate has grown increasingly heated in recent years, and reached a boiling point in 2011 with the IAAF’s controversial ruling that it would no longer recognize women’s marathon world records that were set in mixed-gender events.

The decision effectively nullified Paula Radcliffe’s blistering 2:15:25 world record (London Marathon, 2003) in favour of her third-fastest performance of 2:17:42 (again in London, though this run in a female elite field that started 45 minutes ahead of their male counterparts). But while the London Marathon’s separation of the male and female elite fields attempted to generate more compelling coverage of both races, the IAAF contended that their own controversial ruling was designed to address concerns that male pacesetting of female elites conferred upon the women an “unfair advantage”.

And it’s true, the benefits of pacing in distance running are substantial. Over the marathon distance, women run an average of two minutes faster when paced by men – a statistic that IAAF supporters and distance running purists made much of in the heated debate that followed.

Physiologically, it is far easier to run within or just-behind a pack of runners than it is to lead one. And though the advantages of drafting in distance running aren’t quite as pronounced as they might be in a higher-speed sport like cycling, they certainly play a role, especially at the elite level. There’s also a psychological edge to be had in running from behind; most runners would sooner chase their target than be someone else’s.

All of this adds up to a significant advantage in running with a rabbit – though just how significant varies, depending on who you ask. Distance running pop culture has been known to play fast-and-loose with the figures. In the Prefontaine biopic Without Limits, Bill Bowerman memorably explains that “it takes eight percent more energy to lead than to follow” while imploring his prodigy front-runner to modify his signature racing style. Former U.S. and world champion David Krummenacker put the figure even higher, at fifteen percent.

But in any debate over the advantages of pacing (unfair or otherwise) these figures become of critical importance – particularly when the result of said debate has the effect of writing an incontrovertibly dominant record like Paula Radcliffe’s out of the history books.

So just how much of a benefit does drafting confer on a runner? Sweat Science’s Alex Hutchison explored this question, breaking down a 1971 study by physiologist Griffith Pugh (full text can be found here) in which he examined the oxygen consumption of a solo runner in controlled conditions, versus that same runner in the same conditions, this time running one metre behind another runner.

Unsurprisingly, Pugh’s calculations suggest a measurable energy saving from drafting, one which grows progressively more substantial at the higher speeds typical of short- or middle-distance racing. In the marathon, though less palpable, the benefit is certainly still there. Hutchison puts the ballpark figure as running about one second faster per 400m at 2:48/kilometre pace with the same oxygen consumption. “It’s pretty clear that there’s a big energy saving from drafting,” Hutchison concludes.

Numbers aside, there’s plenty of anecdotal evidence to persuade a distance runner to tuck in behind a rabbit for the early miles of the marathon. When Haile Gebrselassie shattered his own world record at the Berlin Marathon in 2008, he did so with the help of no fewer than four pacers, running behind a veritable wall of marathon talent to bring home a blistering 2:03:59. (Since Geb was over 35 at the time, his now-bested mark still stands as the masters marathon world record.)

But it was Mary Keitany’s 2011 half-marathon performance at the Ras Al Khaimah half-marathon in United Arab Emirates that is rumoured to have raised eyebrows at the IAAF, eventually leading to their controversial women-only ruling. Keitany became the first woman to clock a time under 66 minutes in the half, and set a new world record of 1:05:50, running from gun-to-tape behind a male pacemaker.

The crucial distinction between the use of pacers by Keitany and Gebrselassie, according to the IAAF, is that any of Gebrselassie’s four pacemakers could have decided at any point to stop pacing, and start racing. By virtue of the fact that they are all male, and therefore all in contention for the same placing or records, they are by definition competitors.

The notion of an assigned pacer blazing ahead to victory is unusual, yes, but not entirely unheard of. Paul Pilkington entered the 1994 LA Marathon as a rabbit, only to find the elite field incapable holding his blistering pace. “I did my job by getting out fast, nobody came after me,” Pilkington said in a post-race interview with the LA Times. “I figured as long as I was out there and feeling good, why stop?”

Rather than dropping out at the 25K-mark as planned, Pilkington decided to go for the win, forfeiting his $3,000 payout as a pacer-for-hire, but ultimately pocketing a winner’s purse of more than $15,000. His decision was not well-received by his fellow competitors, but Pilkington insisted that the move was legal. “In every race, the rabbit always has the option of staying in the race,” he explained. Race officials agreed with him.

Mary Keitany’s pacemaker, on the other hand, had no such option. Men and women, though they may compete alongside one another, are not actually racing each other. Keitany’s pacer need not drop out at any point to insure she crosses the finish line first, because he is in contention for neither her placing nor her record. Therefore, Keitany – or any woman running the entirety of a race tucked comfortably behind a male pacer – is given an unfair advantage.

Under the IAAF’s new regulation, women’s times would no longer be eligible for world record consideration if they were run in mixed-gender events. While this precludes the use of assigned male pacemakers, it also removes from consideration any event in which the men’s and women’s elite fields start together, even in cases when female elites only use assigned female pacesetters.

While the ruling places the IAAF squarely in the camp of the distance running purists, who regard elite pacemaking as fundamentally unsportsmanlike, other major institutions have stood in staunch opposition. The ruling was contested by both the World Marathon Majors, as well as the Association of International Marathons. Together they issued a joint statement calling the IAAF regulations confusing, unfair, and not representative of the history of the sport.

The ensuing controversy extended far beyond the ire of the World Marathon Majors, igniting a social media firestorm, and garnering public criticism from marathon heavy-hitters like Deena Kastor and Kara Goucher. Radcliffe, for her part, appealed to the IAAF to revisit their decision, while her sponsor Nike mounted an advertising campaign imploring the federation to “let history stand”.

Following a council meeting in November of 2011, it appeared that the IAAF was prepared to kowtow, at least in part, to mounting external pressure. It issued a clarification stating that the new regulation would not be applied retroactively, but only to those records set going forward. Radcliffe’s 2:15 mark would be allowed to stand.

Although the World Marathon Majors disputed the ruling as it relates to world record consideration, race organizers for the Majors remain divided on the use of pacers in their own races. Both the Boston and New York City marathons do not allow elites to run with assigned pacers, a rule that the Chicago Marathon also adopted this past year. The Berlin Marathon, on the other hand, is famous (or infamous, depending on who you ask) for using teams of pacesetters to pull the elite field along to breakneck finish times. And not without reason; out of the last ten marathon world records, seven have been set at the Berlin Marathon.

For all its attendant controversy, elite pacemaking is hardly anything new. The annals of athletic history are littered with stories of these mercenaries of distance running. In fact, pacemaking played a pivotal role in what is arguably the most mythologized moment in distance running history – Roger Bannister’s four-minute mile.

When Bannister clocked the first sub-four-minute mile at Iffley Road Stadium in 1954, he did so with the help of not one but two pacemakers, Chris Chataway and Chris Brasher. Bannister’s use of pacers to break the elusive four-minute barrier reportedly miffed his long-time rival, Australian John Landy, who regarded the use of pacers as contrary to the spirit of competition. But Bannister’s world record ultimately failed to ruffle feathers in the athletics community the way that Mary Keitany’s half-marathon record did some 57 years later, in part due to the fact that Landy managed to better Bannister’s mark less than two months later.

The problem with pacing is that, at it’s very core, the practice is impossible to fully regulate. One might object to the employment of formal, assigned pacemakers, but in their absence, the line between tactical racing and informal pacemaking – one teammate pacing another to within striking distance of a goal time, the sacrificial lamb on the altar of calculated splits – begins to blur.

Athletic performance will always depend, at least in part on the performance of one’s competitors – on the pace of the pack, and the variable willingness of one runner or another to take the lead. And yes, there will always be the staunch purists who, like Prefontaine, regard tactical drafting as something akin to a less-than-honest race effort.

But like it or not, pacing – both the physiological advantage of drafting and the psychological relief of mentally “checking out” for a few miles – is a part of distance running. The question that the IAAF, and the athletics community more broadly, is trying to answer with attempts to regulate pacesetting is – how much should it be?

Interestingly, there is an argument to be made that mixed-gender pacing actually confers a slight disadvantage on female elites, compared to their male counterparts. Male rabbits pacing male elites typically run directly ahead of their charges – see Gebrselassie’s 2008 performance in Berlin – cutting the headwinds and allowing the athletes to mentally “check out” for large parts of the race.

But pacesetter contracts for female elites often prohibit male rabbits from running out in front, to avoid their appearing in televised coverage of the women’s race – effectively negating any of the benefits of cutting the wind. Which throws into question the notion, so central to the IAAF’s regulations on pacing, of whether female elites paced by men really do have an unfair advantage at all. Does the benefit of side-by-side accompaniment over 25 miles really outweigh that of ducking behind a wind barrier for 20?

This off-to-the-side pacer stipulation may not be characteristic of all pacing contracts, but it has certainly been a salient factor where the women’s world record is concerned. It was certainly the case for pacer Weldon Johnson, who escorted Paula Radcliffe through 25 miles of the Chicago Marathon in 2002, where Radcliffe set her first world record. Rather than leading Radcliffe, Johnson ran alongside her, following her lead as she knocked off splits far quicker than the pre-race agreed-upon pace. “I very consciously ran alongside (him) rather than ever behind,” Radcliffe later recalled.

With Radcliffe fighting wind resistance and hitting her splits relatively unaided, one is tempted to ask what, exactly, was the benefit of running with a pacer at all? Johnson puts it down to camaraderie. “Twenty-six miles by yourself can be very hard,” he says.

And therein lies the critical challenge posed by the IAAF mixed-gender pacing rule; women in the marathon – and especially at the elite level – are relatively thin on the ground. The depth of field for women’s marathon running pales in comparison to the men’s, and the resulting dearth of both female pacers and competitors means that any woman wishing to chase after Radcliffe’s mark must either run with the boys, or go it alone.

The arrangement, disadvantageous though it might be, is not entirely unwelcome among leaders in the women’s running community. Kathrine Switzer, who famously outran the ire of race director Jock Semple in 1967 as the first woman to officially compete in the Boston Marathon, likens the situation to the subsequent struggle to establish a women’s Olympic marathon. Throughout the late 1970s and early 80s, Switzer helped to organize women’s-only marathons in response to the IOC’s refusal to recognize performances by women in mixed-gender competition.

“I felt very strongly, and I still do, that women need the challenge and the forum to accept the responsibility to run a race on their own,” she explained.

Just how swiftly the reigning women’s marathon elite will rise to this new challenge remains to be seen.

Chase big dreams.