How to stop runners 'bonking', or hitting the wall

It might sound like fun, but bonking, otherwise known as hitting the wall, is dreaded by runners. I had had my first 'bonk' a couple of years ago while running 25 kilometres in unseasonably hot weather, following a shoddy training program. Somehow I finished the race, but not without spasmodic legs cramps, a thumping headache and feeling absolutely spent.

For those who aren't familiar with the term, bonking describes the point at which the body's glycogen stores are depleted, your blood glucose level drops, muscles tire and the body starts to fatigue and burn fat, making each stride towards the finish line a battle of mind over body. Bonking hurts - your legs feel heavy, your form begins to fail and your running economy and pace takes a dive.

Body stall

After my nightmarish experience, I vowed to never again let my body stall mid-run, but what strategies should you take to bonk-proof your run?

Chris White is a recreational running coach and the founder of Go Run Australia, which helps runners, especially beginners, tackle their running fears and achieve their goals.

He knows plenty of runners, including him, who have hit the wall hard.

Runners tend to bonk at around the three-quarter mark of a half, full or ultra marathon.

"From my experience, runners tend to bonk at around the three-quarter mark of a half, full or ultra marathon," says White. "That's when running begins to hurt and you suffer. People call it dropping off a cliff because some runners can easily drop three or four minutes per kilometre once fatigue sets in."

White says all runners, including professional athletes, can experience late-race fatigue that affects their performance. He recommends the following strategies to help you prepare mentally and physically, and power through to the finish line.

Strong is the new skinny

White says people used to put a lot of stock in being a light and lean runner, but in recent years there's been a shift towards being a strong runner.

"Supplementing running with strength training makes you a stronger, faster and more efficient runner," says White.


"Body weight exercises, high intensity interval training, yoga and Pilates are all good options to strengthen the running muscles that do most of the work. They'll also improve your posture, breathing and form, which can help stave off a breakdown on longer runs.

"Performing exercises such as squats, lunges, push-ups and planks will strengthen the muscles in the lower back, hips, hamstrings, quadriceps, abdomen and glutes and help prevent muscle burnt out."

The art of pacing

It may seem obvious, but pacing yourself in training and on race day is crucial to warding off late-race fatigue. Pacing is both an art and a science, and is something that runners sometimes get wrong.

White says a lot of runners start out too fast, which can come back to haunt them later in the run.

"In the excitement of race day, it's easy to get caught up in the euphoria and sprint out of the start line. Unfortunately, once you realised you've been setting a cracking pace early in the race, the damage may have already been done," he says.

"Having a pace plan and training at the right pace can help make sure you're race ready, but sticking to the plan in the excitement of race day is the real skill."

Other pacing techniques include:

Negative splitting

This racing strategy involves completing the second half of a race faster than the first half. To do this, you need to intentionally set yourself a slower initial running pace, followed by either a gradual or sudden increase of speed towards the end of the race. The aim is to finish your run feeling strong and passing people, rather than gradually slowing down as you get more and more tired.

White says including negative splits into your training program and race day plan forces you to be conservative early. It also helps prepare runners for the discomfort they might feel towards the later stage of their run.

Run walk

Both seasoned and beginner runners often view walking as a sign of failure, but incorporating walking into your race can help you run better and faster.

"If it's good enough for Ironman athletes to walk through hydration and transition stations, then it's good enough for recreational runners," says White.

"People feel a lot of pressure to run the whole distance, but walking even for one minute every half hour, can help prevent blowing up in the later stages of the race."

White says periodic walking reduces pressure on the muscles, joints, and tendons, and helps lower breathing rate and heart rate - meaning runners are able to cover more distance with better form and alignment, and a reduced risk of fatigue.

Sensible nutrition

Has this ever happened to you? After putting in the hard yards for several months, you enter the taper period of your training plan and reward yourself with carb loading from burgers, beer and ice cream. Or despite reducing your training, you keep eating the same amount of food. Then a few days out from the race, you are carbed-up and beginning to feel heavy.

White says eating too much in the lead up to race day can be detrimental to your performance.

"Don't get tricked into the idea that you have to massively stock up on carbohydrate rich foods like pasta, bread and rice before a race," says White.

"It depends on the length of your event and your own diet, but you can begin carb-loading as early as five days prior by slightly increasing your carb intake and then, in the two days before you race, increasing it again. The trick is not overdoing the carbs so much that you feel heavy and bloated. Many people aim for a carb intake of 10 grams per kilogram of body weight, but it really does depend on the individual."

White recommends eating a good-sized meal of carbohydrates three or four meals before a race rather than the traditional big feed the night before. Adding some salt to your food the day before can also help prevent cramping.

Other nutrition tips include:

● Have a nutrition and hydration plan worked out in advance and test it during training.

● Think about what you are going to feel like eating and drinking late in the race and have it ready to collect at an aid station on course.

● Research where the hydration stations are and if you don't like the sports drink on offer, make other plans so that you don't get caught out.

● Start refuelling before you actually need it. For most people, this is around 40 minutes into your race. Take a drink, gel or whatever you have planned to eat and then repeat around every 30-40 minutes.

● Practise refuelling at race pace in training and know how much carbohydrate you can take on without causing stomach problems.

● If you're running a marathon or a longer distance, particularly in the heat, have a salt tablet handy.

Have you ever been caught 'bonking'? Let Laura know in the Comments section. 

The goal of one day completing an ultra-marathon inspires running fanatic Laura Hill to clock up the kilometres each week. With a day job in the corporate world, Laura loves nothing more than lacing up her runners and hitting the pavement to clear her mind and challenge her body.

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