Facts for runners: scientists and researchers bust the myths

A lot of what you know about joints, posture and diet is wrong. Here’s the latest information from sports scientists.

Before you start running, make sure you have comfortable and supportive shoes and clothes. For Feeling Great 25/8. Thinkstock picture

Running has never been more popular, but for every person lured by its mind-boosting, fat-busting benefits, others will be put off by its reputation as a hardcore sport. What’s more, running entails a set of unwritten rules that may scare off beginners, such as you must drink all the time and must never stop to walk. However, is there any substance to these claims?

Slight dehydration helps you to run faster

Much emphasis is put on the importance of drinking enough during long-distance events and it has been held as fact that a 2 per cent drop in body weight through fluid loss is detrimental to performance.

However, some experts think that is overplayed. New Zealand sport scientists suggest that weight loss of 3 per cent does not slow down athletes, while a 2012 paper in the Clinical Journal of Sports Medicine note elite runners in the Dubai marathon recorded fluid losses of almost 10 per cent yet still ran exceptionally fast times.

“A 2 per cent loss of body weight for a 75kg runner is 1.5 litres of fluid, or 1.5kg less weight that they will have to lug around a run,” says John Brewer, professor of applied sport science at St Mary’s University in Twickenham, Eng­land. “So it is not surprising that, under certain conditions, performance can be improved with a modest level of dehydration.”

Over-drinking can be dangerous

Drinking too much fluid is a risk because it can lead to potentially fatal hyponatremia, or water toxicity. A 2012 study in the British Journal of Sports Medicine found that 12 per cent of runners in the London marathon consumed dangerously high amounts of fluid. On average, 500ml of fluid an hour is recommended during long-distance races. If you drink up to a litre an hour on long runs and also drink a litre of water before you start, your intake will be too high. “It’s quite easy to drink more than you need and, in doing so, put yourself at risk of hyponatremia,” Brewer says.

Walking breaks can help your performance

A recent study in the Journal of Science and Medicine in Sport found that runners who took planned walking breaks not only finished as quickly as those who ran the entire distance but had less muscle pain at the end.

German researchers looked at 42 runners who trained for 12 weeks before their first marathon. A week before the event, the runners split into two groups: those who ran the entire way and those who took 60-second walking breaks every 2.5km. After the 42.2km race, both groups finished with similar times. But 40 per cent of the participants who ran the entire distance reported “extreme exhaustion” at the finish line, compared with less than 5 per cent of the run-walk group.

“For some people, scheduled bouts of walking are a useful means of covering the distance and can also make it psychologically easier,” says UK Athletics running coach Paddy McGrath.

Running won’t wreck your knees

Running a marathon? You may as well take a hammer to your knee joints. At least that’s the entrenched belief of non-runners who claim that it causes arthritis and ruins knees. Experts beg to differ. In 2013, a study of 75,000 runners in the journal Medicine & Science in Sports & Exercise showed that, provided they had healthy knees to start with, runners had less overall risk of developing arthritis than non-runners, even if they jogged into their 40s, 50s and beyond.

Mark Batt, director of the Arthritis Research UK Centre for Sport, Exercise & Osteoarthritis, says running is in one direction, with no twisting and turning, which could make it more joint-friendly than, say, football. Even first-time marathon runners, widely believed to be more prone to injuries, are no likelier to suffer knee damage than long-term runners, say researchers from Germany’s Freiburg University Hospital. “High-impact forces during long-distance running are well tolerated even in marathon beginners,” they note.

The barefoot running fad can cause injuries

In recent years, runners have embraced minimalist footwear, or shunned shoes ­altogether, believing it makes running easier, speedier and less injurious. Physio­therapists saw a rise in injuries among the barefoot brigade and scientists have cast doubt on the approach, with studies at Brigham Young University in Utah showing it doesn’t toughen foot muscles, one argument in favour of skimpy shoes. “Footglove” manufacturer Vibram agreed to settle a US lawsuit that alleged false claims were made about the footwear’s health benefits.

The heavier your trainers, the better

This year’s trendsetter in the trainer market is the “maximalise” shoe, with thick, heavily cushioned soles. Sales of chunky-soled brands such as Hoka One One ($200-$240, hokaoneone.com.au) are rocketing, while Brooks (brooksrunning.com.au) reported a 29 per cent increase in sales of its most cushioned shoes last year.

“Many minimalist shoes don’t offer enough protection and support for long-distance running,” says runner Matt Roberts. “You need a trainer with good structure that doesn’t allow too much foot movement as you stride.”

A high-protein diet will slow you down

Kevin Deighton, an exercise scientist at Leeds Beckett University in Britain, says carbs do matter if you run long distances.

“Low-carbohydrate diets became popular among some runners in recent years because it was found that increasing the fat content of the diet spared carbohydrate stores and led to fat stores being used for fuel instead,” he says. “However, if you are running distances, carbohydrates provide the fastest supply of energy and you need them to maintain your pace.” Training for a 10km, half or full marathon on a low-carb diet could be disastrous.

“It’s been shown to impair recovery and raise the risk of injury,” Deighton says. “You need protein and fat in adequate amounts to aid the repair of muscle tissue and provide essential nutrients, but the diet of a regular long-distance runner should be particularly high in carbohydrates.”

Brewer says the amount of carbs needed increases with the distances run, but it should remain proportional to distance.

“Most runners will use 2500-3000 calories running a marathon, equivalent to about a day’s food intake,” he says. And the faster you run, the more carbs you use up. “If you set off too quickly, you will burn carb stores too quickly and risk depleting them or hitting the wall. Maintain a manageable pace and you will burn fat as well as carbs, and hopefully have enough glycogen to get to finish the run.”

Treadmills are not a soft alternative

David Siik, a Ford model and running coach who developed the Precision Running treadmill class at Equinox, says there is an “inverse snobbery” towards the treadmill, with many runners deriding it as a soft alternative to running outdoors.

Its reputation wasn’t helped by a British study a few years ago that suggested a running belt should be cranked up to an incline of 1 per cent to get the same benefits you would reap from running outside.

Biomechanics experts have debunked this as an urban myth because the study’s findings applied only to speedsters who ran faster than four minutes a kilometre.

Others also have discounted the belief that the treadmill belt propels you forward so you do less work. The key, says Siik, is to mix it up. “Just plodding on a treadmill won’t get you fit,” he says. “You need to factor in elements of speed, up to 5 per cent incline, duration and recovery, and you can get the biggest burn possible in the time you are on it.”

You can’t use running as an excuse to snack

As many runners have discovered, going on regular runs does not always help you to lose weight. That’s because running is not a green light to start devouring calories by the bucketload.

Many find that they gain weight rather than lose it, especially if they gobble up high-calorie sport drinks and energy bars on top of their usual diet.

“In real­ity, it’s not that easy to lose lots of weight through distance running,” Brewer says. “To lose 1kg in body fat, you need to burn about 8000 calories more than you consume. Most people burn about 100 calories per mile (1.6km), so that’s (about 130km) of running just to lose one kilo, even if you don’t eat any extra.”

Even during a marathon, you can expect to expend only 2800 calories on the 42.2km route. To put that into context, an average man needs about 2500 calories a day to maintain his weight; a woman about 2000 calories.

A perfect gait is not essential

Runners have been led to believe that a flawless running style is essential for injury reduction and speed. Shops and clinics offer gait analysis to provide information about your foot-strike, stride pattern and pronation (or lack of it), in the hope that you will adopt a Mo Farah-type technique. Is it necessary? Experts think not.

Running coach Martin Yelling says many elite runners don’t have perfect technique. “Getting stressed about changing your running style is unnecessary and can cause tension,” he says. “A slightly ragged but relaxed style is better than trying to adopt something that feels unnatural.”

Researchers at Britain’s University of Exeter say most runners self-adjust, settling into an efficient technique by running more.

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