You are running at a steady pace with most of the marathon behind you. You have just another 10km to cover before you reach the finish line. It shouldn't be too difficult, you think to yourself.
All of a sudden, an immense wave of fatigue sweeps over you. You become dizzy and disoriented. Every step becomes an agony. You struggle to finish that last 10km that seemed so manageable mere moments ago.
This phenomenon, known as the 'Wall', is a relatively common occurrence in endurance sports. It happens to about 40 – 60 per cent of non-professional marathon participants, according to figures from various news reports and websites.
"The 'Wall' is usually caused by the depletion of glycogen (stored carbohydrates) in the muscles and liver," explained Ms Carolyn Vethappriya, a performance nutritionist at Singapore Sports Institute, Singapore Sports Council. News reports note that this typically occurs around the 30km mark, though it may also happen earlier.
For those training for marathons, such as the upcoming Standard Chartered Marathon Singapore (SCMS), it is important to learn how to avoid hitting the Wall. A full marathon typically stretches for 42km, meaning that participants may encounter this phenomenon after they cross the halfway mark.
AsiaOne Health finds out how you can overcome the Wall from experts from Singapore Sports Institute, Singapore Sports Council (SSI). The Singapore Sports Council is the organiser of the Standard Chartered Marathon, which will be held on Dec 4.
Coping and preventive measures
What can you do when you hit the Wall?
"Milder versions of the Wall can be rectified with the ingestion of food and fluids that contain carbohydrates," said Ms Vethappriya. These include carbohydrate gels, glucose water, sports drinks, bananas or lollies.
However, a better approach is to take measures to prevent the condition in the first place.
"Eat and drink to a plan which helps to maintain glycogen levels in the body throughout the exercise session," advised Ms Vethappriya. "An athlete should learn to eat and drink right, develop an appropriate nutrition plan from the beginning and stick to a familiar routine."
Some athletes may benefit from a dietary strategy known as 'carbo-loading'. Ms Vethappriya explains that this involves making changes to the athlete's carbohydrate intake and training routine so as to maximise carbohydrate stored in the muscles before the competition. "This has been shown to enable athletes to exercise at an optimal pace for longer," she told AsiaOne Health.
However, she noted that "not all athletes require carbo-loading nor benefit from it."
To find out if this works for you, work with a sports nutritionist or dietician and try the carbo-loading plan long before the marathon period, advised Ms Vethappriya. "Some athletes mistake this strategy as an excuse to 'gobble-down' everything and anything in sight," she said, adding that doing so can result in "unnecessary fat gain and compromise sports performance".
Training with your mind
Proper training and race management can also help runners manage and delay the effects of the Wall, said Ms Tay Hwei Chin, a performance psychologist from SSI.
"While weekly, progressive long runs in the training programme help muscles adapt and build physical endurance, runners have to mentally plan and pace their runs to manage progressively longer distances," noted Ms Tay. "They can plan their strategies around key areas for a successful run, such as by sticking to an optimal starting pace, building momentum at appropriate stages of the race and using arousal modulation techniques to sustain the right pace and complete the last stretch."
"Some athletes also use dissociative strategies to help them push on and complete the latter part of the race," added Ms Tay. Such techniques include mentally distancing oneself from one's fatigue or thinking or visualising about being at the beach or a point ahead, she said.
"Other athletes also use positive self-talk and motivational thoughts to psych themselves up during the harder parts of the race," she told AsiaOne Health.