Hitting ‘the wall’ is something most serious endurance athletes would have experienced during their careers, but none actually enjoy
Hitting ‘the wall’ describes a condition where the glycogen stores in your muscles and liver are completely depleted (i.e. your body is without carbohydrates, your primary source of fuel) which in turn leads to serious fatigue and quite possibly an end to your marathon. Traditionally it was thought by sport scientists that this was an inevitable part of running a marathon and couldn’t be avoided, but a recent study conducted at Harvard University disagrees and the author Benjamin Rapoport claims to have developed a mathematical formula to prevent athletes ever running out of energy.
An experienced runner himself, Rapoport believes the amount of carbohydrates needed before a race (and therefore needed to avoid hitting the wall) is dependent upon: the distance of the marathon, the runner’s weight and the intensity and speed at which they intend to run the marathon. He represents this theory in the following equation:
Carbs needed = marathon distance X bodyweight X intensity factor
This goes against conventional wisdom which believed athletes were only capable of storing enough energy (carbohydrates as muscle glycogen) to get them to the 21 mile mark (33–34 kilometres.) Instead Rapoport believes if you plan the speed you wish to run at (and the time you want to finish the marathon in) and are aware of your energy constraints as dictated by your ability to store muscle glycogen (weight in kg) and VO2 max (this is essentially the maximum amount of oxygen you can uptake and use) you will be able to finish the marathon without hitting the wall at all.
Rapoport acknowledges that calculating your V02 max is quite difficult and it’s essentially the maximum amount of oxygen you can utilize during intense or maximal exercise. Put very simply, and ignoring other factors, the higher your V02 max the quicker you will be able to run a marathon (therefore it has a huge influence on the last part of Rapoport’s calculation, ‘intensity factor.’) It’s measured in millimetres of oxygen per kilogram of bodyweight per bodyweight per minute and the highest ever recorded VO2 max is 94 ml/kg/min in men and 77 ml/kg/min in women, both were cross-country skiers (Astrand P-O and Rodahl K. 1986). Elite athletes usually have a V02 of 70 ml/kg/min and the average person has a VO2 Max of around 35 ml/kg/min.
To calculate the amount of carbohydrates needed to run your desired marathon time, try the online calculator created by Rapoport here: www.endurancecalculator.com which calculates the exact amount of carbohydrates you need 48 hours before a marathon. And to ensure you are able to consume sufficient quality carbohydrates both before and during the race, visit Myprotein.com who has a comprehensive range of carbohydrates, including isotonic drinks, bulk powders you can easily mix in a shake and high carb snacks all designed to fuel your marathon:
Instant Oats are a fantastic source of low Glycemic Index (GI) carbohydrates that have been milled down in to an ultra-fine powder so it can be easily consumed as a drink when mixed with your preferred liquid. 100 grams will provide 70.7 grams of quality carbs and is only £2.39 for 1kg. www.myprotein.com/uk/products/instant_oats
Tri Carb is a high quality carbohydrate energy drink designed to fuel your exercise from beginning to end. This formula has been created to ensure maximal carbohydrate absorption through its unique blend of 3 different carbohydrates, Palatinose, Maltodextrin and Fructose. 100 grams will provide 94 grams of carbs and is £7.99 for 800g. www.myprotein.com/uk/products/tri_carb
MyBar Oats and Whey is a meal replacement bar containing 43.8 grams of carbohydrates per bar and 22 grams of protein. Ideal for fuelling the muscles, it contains the ratio 2:1 carbohydrates : protein. Each box contains 18 x 88g bars and is £20.99 per box. www.myprotein.com/uk/products/oats_and_whey
Check out the online calculator here: www.endurancecalculator.com
Ross Edgley
Sports Scientist with a BSc Degree in Sports Science from Loughborough University Ross Edgley was a Strength and Conditioning Coach at The English Institute of Sport working alongside Britain’s Olympic Physicians, Nutritionists and S&C coaches and is currently fitness and nutrition advisor to a range of celebrities, athletes and what is considered the UK’s most innovative sports nutrition company http://www.theproteinworks.com