THE 2: 00: 00 MARATHON – WHAT IT WOULD TAKE

Our secret dreamer is likely to be in his early 20s to mid 30s. Age-based performance data compiled by the World Master’s Association suggests that the optimum age for male marathoners is 23-35 (though a 36-year-old would experience only a trivial, 7-second handicap). Dennis Kimetto was 30 when he set the current record. Australian Robert de Castella was 24 when he set the mark at 2:08:18, in 1981. The marathon is a race that rewards both talent and the discipline that comes with experience, allowing youngsters and seasoned veterans to contest on even footing over a fairly wide range of ages. Marathoners tend to be lean and fine boned. A well-known rule of thumb is that each unneeded kilogram of body weight costs about two extra seconds per kilometre. Even upper-body strength, once thought to be an advantage for biomechanical efficiency in running form, may come at a cost in muscle strength. In the months leading up to the Rio Olympics, the US’S top hopeful, Galen Rupp, reduced his upper-body strength training and cut muscle mass from his pecs, abs and biceps, according to John Brant, co-author of the 2013 autobiography of Rupp’s coach, Alberto Salazar. Apparently it worked: Rupp won bronze in a strong field. Our secret dreamer is likely to come from a family of accomplished runners who not only inspired him, but also bequeathed him the perfect genetics.

The mother of America’s top female finisher in the Rio Olympics, Shalane Flanagan, once held the women’s world record in the marathon, and both parents represented the US in international cross-country competition. Family members tend to have similar body builds, but the shared heredity may also affect physiology. In 1992, scientists in the US and Canada put more than 600 sedentary people on training programs and discovered that there was a wide difference in how well they responded. Some made enormous leaps in fitness; others actually got less fit. This indicates that genes are important, especially those that enhance the body’s ability to adapt with training. Human muscles contain two types of fibres, slow-twitch (Type I) and fast-twitch (Type II) – the names refer to how quickly they can contract. There are also two basic types of fast-twitch: Type IIA and Type IIB.

Fast-twitch fibres, especially Type IIB, are best suited for explosive activities such as springing and powerlifting. But they fatigue quickly. Slow-twitch fibres aren’t as good for sprinting, but have much more endurance, while Type IIA fibres sit in the middle, with both speed and a higher degree of endurance than Type IIB.

Our secret dreamer’s legs will need to be composed mostly of Type I fibres, probably augmented by a nice admixture of Type IIA. To a large extent, this will be another hereditary factor, like his build and the ability of his body to adapt to training, but he will want to do the right things in training to develop the fibres he has, and avoid bulking up on useless Type IIB fibres. Luckily, the training that does this is the same training he needs for building his aerobic system. Vo2max is a measure of the amount of oxygen your body can process at peak effort: a gauge of the power of your aerobic engine, with all the parts – heart, lungs, capillaries, and muscles – working at their best. A 3:20 marathoner – the type who might see significant success in local races – might have a Vo2max of 45 to 50. (Units are ml of oxygen/min/kg of body mass.) Elite marathoners tend to have values in the 80s, and our special dreamer would definitely want to be in that range.

Many people equate aerobic power with having a strong cardiovascular system. And that’s definitely part of it. A sedentary person’s heart might be able to pump two litres of blood per minute, but an elite’s can pump 40 litres per minute, says John Halliwill, an exercise physiologist at the University of Oregon. But high Vo2max also requires large numbers of capillaries supplying blood to the muscles, plus muscle cells well stocked with mitochondria – the subcellular powerhouses that turn fuel and oxygen into energy.

To a large extent, our secret dreamer’s Vo2max will be determined by his heredity; if his parents gave him the wrong genes, he has little chance of developing an elite Vo2max, no matter how determined he is. Even with the right genes, he’ll reach a point where he will have elevated his Vo2max as far as his genes allow. In a 2005 study in the Journal of Sports Medicine and Physical Fitness, a team led by Alejandro Legaz Arrese of the University of Saragossa, Spain, tracked 33 elite Spanish runners through four years of intense training. At the end, the runners’ Vo2maxes were essentially unchanged. “In a nutshell,” Halliwill says, “Vo2max reaches a plateau.” Training is still needed to keep from backsliding, “but further gains in speed have to come from somewhere else”. That “somewhere else” begins with efficiency. However high our elite dreamer’s Vomax might be, it’s not going to do him much good if he hits aerobic max

at a pace others would see as a brisk jog. It would be like driving a racecar in sand. His engine might be able to blow an enormous amount of energy, but he won’t set any speed records.

Part of the solution involves detailed attention to running form. Bouncing, overstriding, leaning too far forward, or leaning too far back can all squander energy.

Our dreamer must also have strong legs, because strong muscles more effectively function as springs that store and release energy with each stride. In a 2015 analysis in the Journal of Strength and Conditioning Research, a team led by Carlos Balsalobre-fernández of the University of Madrid found that a mix of weight lifting, bounding exercises, and short sprints improved running economy by 2-3% in serious but not world-class athletes. Lactate is a molecule produced from the initial steps of the muscles’ breakdown of glucose for energy. It makes up about half a glucose molecule, says John Halliwill, an exercise physiologist at the University of Oregon. Runners have long blamed its buildup in the blood for the onset of fatigue, but that’s incorrect. Research by George Brooks, an exercise physiologist at the University of California, Berkeley, has found that the body uses the blood to ship lactate – which can be thought of as a lower octane fuel than glucose – to lesserworking areas that can easily use it, such as the heart, brain, liver and arm muscles, sparing high-octane glucose for the legs.

Italian coach Renato Canova, who has trained some of the world’s best Kenyans, is notorious for following runners around on training runs and drawing blood, just to check lactate. Nike coach Alberto Salazar, who in 1981 ran the world’s then-fastest marathon at 2:08:13, remembers having his lactate levels taken so many times via finger-prick tests that he complained of running out of unpricked fingers. Our secret dreamer may or may not subject himself to this many blood tests, but he and his coach will know that when it comes to marathon training, “lactate” is the name of the game. There is a well-known relationship between shoe weight and running economy: each 100 grams of unneeded weight removed from the shoes means a 1% improvement in efficiency.

Modern shoes are already light, but it may be possible to shave off another 50 grams, says Ned Frederick, a biomechanics expert at Exeter Research Inc. in Brentwood, NH – enough to give our secret dreamer a “free” 30 seconds.

Historically, runners have simply tried out different types of shoes until they found what they liked, but Kramm thinks it’s possible to use treadmill tests to match runners to their perfect shoes. It might also be possible to match the shoe to the course, perhaps by designing shoes that change cushioning and flexibility as the runner tires. “Individually tuned shoes won’t trump talent and training, but could easily add up to the necessary seconds,” Frederick says.

If our secret dreamer is thinking of dumping his shoes entirely, as some runners have, he may want to reconsider. In a 2012 study in Medicine & Science in Sports & Exercise, Jason Franz and Roger Kramm of the Locomotion Laboratory at the University of Colorado put experienced barefoot runners on a treadmill and discovered that however fond of barefoot running they might be, their oxygen consumption was 3-4% less efficient barefoot than shod. Currently the fastest courses on the planet are those used for the Berlin, London, and Chicago marathons, but ideally our runner’s marathon would be run on a track. The 10,000-metre record on the track is 26:17.53, versus 26:44 for roads, due in part to the track’s perfect, ideally cushioned surface. A comparable effect in a marathon would be nearly two minutes – almost two-thirds of what our secret dreamer needs.

The 1968 Mexico City Olympics, run at an elevation of 2,200 metres above sea level, showed that high elevation slows down distance runners, by about 1% per 300 metres of elevation. If the reverse effect applies below sea level, a race held at the Dead Sea (-420 metres) might give a whopping 90 second advantage. If someone were to build a track there, our secret dreamer would be very much in business. However well trained our secret dreamer is, he’ll need good weather to make his big mark on race day: no wind and not too hot. In fact, he’ll want temperatures most people would view as downright chilly.

Recreational runners are often told that the ideal temperature for a race is between 10°C and 13°C, but a 2007 study in Medicine & Science in Sports & Exercise, led by Matthew Ely, then a scientist at the US Army Research Institute of Environmental Medicine in Massachusetts, found that even at temperatures of 10°C-15°C there was a 1-2 minute drop in performance.

One thing our secret dreamer likely will not see on race day is a pacer. Marathon world-record attempts are generally assisted by runners in whose slipstreams the anointed stars glide for as much as 30 or more kilometres into the race. But who is going to pace an attempt at a sub-2:00 marathon? asks American marathoner Ryan Vail. “Those guys would be the very ones attempting the world record,” he says.

It’s possible he could have done even better: in the 1954 Commonwealth Games, he entered the stadium on pace for a 2:07 finish, but repeatedly collapsed in the final 400 metres and failed to finish. (He was later hospitalised, unconscious.) Had he been a little less aggressive, could he have beaten the times set by Clayton the following decade? He’ll never know. The Commonwealth Games were his last race. “I was lucky not to have died that day,” he later said.

Since then no other such breakthrough racers have surfaced, but the record has continued to fall. Since 2000, it has dropped seven times, totalling 2 minutes and 45 seconds. If that rate of progress continues, a 2:00 marathon could happen sometime in the 2030s.

Who might that super marathoner of the near future be? Since long-distance runners tend to peak in their late 20s or early 30s, our secret dreamer could be a teenager today. But he could also be older, maybe already making his mark on the roadracing scene. Some observers think a crescendo of interest – fed by a rise in sponsorship money, prizemoney incentives and ever-more sophisticated training methods – could produce a sub-2:00 marathon much sooner.

Yannis Pitsiladis, a professor of sports and exercise science at the University of Brighton, England, is one of the believers. Pitsiladis, the lead contact for the Sub2 Project (sub2hrs.com), has said he thinks an investment of $30 million in technology and incentive prizes could make it happen. His project’s website proclaims that it’s “no longer a matter of if but when”.

Geoffroy Berthelot, a specialist in informatics and algorithmics at the National Institute of Sport, Expertise, and Performance in Paris, France, thinks that “when” may arrive sooner than expected. “Who knows if a ‘Usain Bolt’ marathoner might not come along next year?” he says, referring to the Jamaican sprinter who won three gold medals in the 2016 summer Olympics in Rio de Janeiro, Brazil.

Our secret dreamer knows that getting to 2:00 will take a rare combination of talent, toughness, perseverance and training. In the marathon, much of that training centres on improving three physiological variables: Vo2max, lactate threshold, and running economy. (See infographic on pages 46-48.) If the highest known values of all three of these were ever combined in a single person, that person should be able to break two hours – with several minutes to spare, says Michael Joyner, MD, an exercise researcher at the Mayo Clinic, Minnesota, who examined the question in a 2010 paper in the Journal of Applied Physiology and in subsequent unpublished research.

But hitting the mark will also be, to some degree, a matter of luck. It will require “everything going perfectly – weather, pacing, preparation, etc,” says Dathan Ritzenhein, the US’S third-fastest all time marathoner (2:07:47, Chicago, 2012). “It’s very hard to put all the pieces together, but I do think it will happen.” RICHARD A. LOVETT is a Portland, Oregon-based science writer and science fiction author.

IMAGES 01 Adrian Dennis / AFP / Getty Image 02 Popperfoto / Getty Images 03 Allsport Hulton / Archive / Getty Images Anthony Calvert

IF THE CURRENT RATE OF PROGRESS CONTINUES, A 2: 00 MARATHON COULD HAPPEN SOMETIME IN THE 2030s.