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Simon Hart investigates what elite endurance athletes mean when they ‘hit the wall’ and how to overcome it

While hitting the wall can end in complete collapse in extreme cases, most runners experience it through a significant slowing of pace in the final miles. It may not be so physically dramatic, but it is ruinous if you have a time target. In a recent study that sheds new light on the impact of the wall on performance, Irish academic Professor Barry Smyth analysed the performance of 717,000 individual marathon runners over a five-year period, comparing their splits from 25k to the finish with their pace from 5k to 20k. Those whose pace slowed by 20 per cent or more were deemed to have hit the wall. Professor Smyth found that 28 per cent of male runners hit the wall, compared with 17 per cent of female runners – statistics that remained constant for elite, sub-elite and recreational runners.

Prof. James Morton, Director of Performance Solutions at Science in Sport

You’re cruising along and the finish line is seemingly within easy reach when suddenly your body says otherwise. Your legs begin to feel extremely heavy, as if you are running through cement, and a feeling of utter exhaustion starts to take hold. Every stride becomes a battle of will, but your body is just not cooperating. Your energy is draining away. No matter how much you want to maintain your pace, to achieve the target you set yourself, your body simply refuses to respond. It is like a car running out of fuel. You may feel dizzy or light-headed, possibly nauseous too, and your pace drops significantly. In extreme cases, your legs start to buckle, your body shuts down and you can no longer move. You have hit the wall, like thousands of marathon runners before you, and there is no way around it. But it doesn’t have to be like this. As the 2023 marathon season gets under way, it is important to know that ‘the wall’ can be avoided with the right preparation, diet and in-race management.

WALL OF FAME

Professor James Morton, Professor of Exercise Metabolism at Liverpool John Moores University and Director of Performance Solutions at Science in Sport (SiS – the world-leading endurance nutrition brand) is one of the UK’s foremost experts in sports nutrition. He explains the reason why some runners hit the wall: “The predominant fuel source that we burn during marathon running is carbohydrate. This is stored as glycogen in our muscles and liver. “Our bodies can probably only store around 400-500g of glycogen, so it's important to arrive on the start line with the liver and muscles fully loaded with carbohydrates.

Of all the thousands, perhaps millions, of runners who have known what it is like to hit the wall, none has achieved such worldwide attention for their heroic meltdown as Dorando Pietri. At the 1908 London Olympics, the Italian athlete staggered into White City Stadium for the final lap of the marathon in extreme physical distress and collapsed so many times that he had to be helped to the finish line by stadium officials. It took him 10 minutes to complete the last lap. American runner Jonny Hayes finished 32 seconds behind Pietri in second place but, after a protest by the US team at the help received by the Italian, he was promoted to the gold medal position, with Pietri disqualified. Pietri’s valiant effort had such an impact on the public consciousness that, as compensation for his forfeited gold medal, he was presented with a silver cup by Queen Alexandra. The Italian’s heroism went viral, Edwardian-style. A century before crowd-funding became a thing, a national newspaper ran a fund-raising campaign to help Pietri open a bakery in his home town in Italy. The fund raised £300 (equivalent to £33,000 today).

Men who hit the wall suffered a slowdown of 40 per cent when their splits were compared, losing an average of 31.5 minutes of time. Women slowed by 37 per cent, losing an average of 33.2 minutes. The research also concluded that faster runners paid a bigger price when hitting the wall, presumably because they took greater risks when chasing faster personal bests compared to slower runners.

If you want to get to the finish line without encountering the wall, then carbohydrate is your friend. It cannot be overstated how important it is to consume the correct amount of carbohydrates the day before the race and to replenish your carbohydrate stores during the race. Professor Morton says runners should consume at least 8g of carbohydrates per kilogram of body mass the day before the race. This should be in the form of simple carbohydrates that are easily digested such as white bread, white pasta, rice, cereals, pancakes, energy bars and carbohydrate drinks. On the morning of the race, Morton recommends a very simple, low-fibre breakfast to avoid any mid-race stomach discomfort. “Interestingly, there was a study carried out at the London Marathon many years ago that looked at runners and how much carbohydrate they had the day before the race,” says Morton. “Those runners who consumed more than 7g per kilogram body mass had completely different pace profiles to those who consumed less. “The ones who consumed 7g and above were better able to maintain an even running pace throughout the race, whereas those who had less saw their pace decline and decline because their fuel stores were running out.”

how to avoid THE WALL

PRE-RACE NUTRITION

MID-RACE NUTRITION

Rookie mistake! Even the great Ethiopian athlete Haile Gebrselassie has made a mistake when it comes to the marathon. When he made his debut in London in 2002, he drank only watr instead of carbohydrate drinks. He paid the price when he hit the wall after 23.5 miles and came home in a very weary third place. A spokesman for his management team commented: “Haile never used carbo drinks before and therefore decided to drink water. He will for sure drink a carbo drink at his next marathon.”

TRAINING The best training to avoid hitting the wall is your weekly long run, gradually increasing the distance until you reach 20 miles. Don’t build up the distance too quickly or you will risk injury. During your long runs, you should experiment with taking nutrition such as Science in Sport (SiS) energy gels or electrolyte drinks, building up the amount of carbohydrate you consume to prepare for the 60g per hour you will need during the race itself. This will train your gut to break down fuel while running and maintain your glycogen stores. Your long runs will also increase your body’s capacity to store greater amounts of glycogen in your muscles, delaying the onset of fatigue and helping you to maintain your pace. The amount of nutrition you need and can tolerate will vary from individual to individual, but by the time your long runs have hit 20 miles, you will have a good idea about the best nutritional regime to sustain you over the distance. Professor Morton says: “It's really about practising in your long runs whether you want to do all gels or mix and match between gels and fluids, or even have all fluids. You should certainly be practising this in the last six to seven weeks before the marathon so that you can come up with a fuelling plan and refine it in the build-up to the race.”

PACING Getting the pace right is a question of mathematics. Assuming you have carb-loaded correctly and are consuming the correct amount of nutrition mid-race, there will be a pace that you are able to sustain for 26.2 miles without running out of glycogen and hitting the wall. Knowing what that pace is comes from training, building your understanding of what effort you can keep up for the entirety of the race, without dropping your speed in the final stages. Once you have a finish target time in mind and know your target pace per kilometre or mile, you need to be patient and self-disciplined from the start to ensure you stick to your plan. Even-paced splits are usually the most successful strategy. This means your target pace will feel a lot more comfortable in the early part of the race compared to the final miles, when you will need to put in more effort to maintain an even pace and avoid slowing down. That is why maintaining full glycogen stores is so important and can be the difference between getting that PB or not.

MENTAL STRATEGY While hitting the wall is a physical phenomenon, there are mental strategies you can use to cope with the onset of fatigue. Paula Radcliffe, the former marathon world record-holder and world champion, famously counted to 100 over and over again to keep her mind off the pain and focus on her race rhythm. Following her 2007 New York Marathon victory just nine months after giving birth to daughter Isla, she revealed she had repeated the mantra ‘I love you Isla’ in her head to keep her rhythm and maintain positive thoughts in the final couple of miles. Interestingly, this kind of internalised thinking to cope with the mental challenge of running a marathon is backed by academic evidence. Researchers have discovered that runners who focus on internal thoughts are less likely to hit the wall than those who try to distract themselves from the pain by focusing on external things such as other runners, spectators or the local scenery. When things get tough and negative thoughts start to take hold, an energy gel can also deliver an instant mental boost and a distraction from the pain of running a marathon. Professor Morton explains: “We have receptors in our mouths and, regardless of the taste profile, the mouth can actually sense the presence of carbohydrate, which will then send a signal to the brain. The brain therefore instantly detects the carbohydrate and it almost reduces the perception of exercise. “The carbohydrate will reach the bloodstream within minutes and will reach the muscles a little bit after that. So, within 10 to 20, you can start effectively burning that carbohydrate for energy.” The problem is that if you have already hit the wall, then this carbohydrate pick-me-up will be too little, too late. At this point, it is best to stop, re-group and then re-start at a gentle pace to get yourself to the finish line. The wall is real – but if you can’t break it down, there are always ways around it.

IT COULD HAPPEN TO ANYONE

telling your body to go but your muscles don't respond'

The so-called 'wall' is the point during the marathon at which your glycogen stores have reached a critically low level

Mohamed Reda El-Aarby, elite marathon runner and SiS ambassador

the wall

It is the moment that every marathon runner dreads.

'When I hit the wall in Seville in 2022, I just felt very heavy and was struggling to lift my legs. Mentally, you really want to do it but physically you can't. It just felt like I had a huge weight on my body.'

The Science

THE MARATHON:

down

2-4g

500g

“Depending on how fast you run, you will be burning carbohydrates at a rate of between 2-4g per minute. “If you have started the race with 500g in your tank, and you're burning 3g a minute, then you're burning 180g of carbohydrate per hour. “That means that after two to three hours, your resources can become depleted.

180g

More recently, the 2022 New York Marathon was the scene of similar drama. Brazilian athlete Daniel Do Nascimento, the fastest marathon runner of all time born outside the continent of Africa, held a two-minute lead by the halfway mark after setting an aggressive pace. But the huge effort of running most of the race on his own took its toll when he collapsed just after 20 miles. As he lay prostrate on the tarmac, second-placed Kenyan Evans Chebet sailed past him on his way to victory in a classic hare-and-tortoise finale.

Far left Daniel Do Nascimento in the 2022 New York Marathon

Men slow by

Women slow by

The most important piece of advice Professor Morton gives to runners is to have a pre-race nutrition plan. You need to know how much to consume, when to consume it and therefore what feed stations you need to use along the route. The bottom line is that marathon runners need to consume around 60g of carbohydrates per hour to replace the energy they are expending, otherwise their fuel stores will eventually run out (although this will vary from athlete to athlete). How you get this amount of carbohydrate into your body while running comes down to individual preference in terms of energy gels, chews or carbohydrate drinks, but it needs to be practised in training to avoid stomach distress during the race. Morton says: “An SiS GO Isotonic Energy Gel contains 22g of carbohydrates, so that means you need to take three per hour. You could also consume a sports drink like the SiS GO Electrolyte drink, which contains 36g of carbohydrates within a 500ml solution.” Apart from not consuming enough carbohydrate, Morton says a frequent mistake that runners make is not feeding right from the start. “A lot of runners don’t feed for the first 60 or 90 minutes until they are hungry, but at that point the damage has been done because you have already been tapping into your fuel stores and depleting them,” says Morton. “If you can feed from the beginning, then you’re constantly topping up your fuel source.”

The SiS products that help elite marathon runners

Even the great Ethiopian athlete Haile Gebrselassie has made a mistake when it comes to the marathon. When he made his debut in London in 2002, he drank only water instead of carbohydrate drinks. He paid the price when he hit the wall after 23.5 miles and came home in a very weary third place. A spokesman for his management team commented: “Haile never used carbo drinks before and therefore decided to drink water. He will for sure drink a carbo drink at his next marathon.”

A quick and convenient way to get a boost of energy. These use maltodextrin as a carbohydrate source and maintain a low-sugar profile with no need for extra water.

Powder drink that delivers carbs and protein, as well as electrolytes and vitamins and minerals. For consumption immediately after exercise.

An alternative dual-source carbohydrate gel (40g carbohydrate per gel). Available in orange, strawberry and lime.

Tablets to give runners a handy effervescent solution to replacing electrolytes lost through sweat.

An energy powder, containing a blend of easily digestible and quick supply of carbohydrate as well as electrolytes (like sodium).

SiS GO Isotonic Energy Gels

SiS REGO Rapid Recovery

SiS Beta Fuel Gel

SiS HYDRO

SiS GO Electrolyte

Team GB Olympic marathon runner Stephanie Davis

37%

40%

Science in Sport is working with Telegraph Media Group to help endurance athletes achieve their marathon ambitions. SiS supplies over 320 elite teams and organisations worldwide offering gels, powders and bars focused on energy, hydration and recovery. It has partnered with 2022 World Athletics women’s marathon winner Gotytom Gebreslase and the Elite Running Team, made up of over 100 world-class athletes. Head to SiS to learn about their role in elite sport and the products they offer runners and other endurance athletes.

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“At that point, you cannot maintain the same running speed you had at the start and your running speed declines. This is what is meant by ‘hitting the wall’.”

'Once you've hit the wall, your total carbohydrate availability is already on the slide, Putting some carbohydrate back in is only going to partially restore it.'

Prof. James Morton, Director of Performance Solutions at Science in Sport

When hitting the wall

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When hitting the wall

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THE Science

WALL OF FAME

AVOIDING THE WALL

IN NUMBERS

THE Science

AVOIDING THE WALL

'Your brain is