No sweat: How can marathon runners avoid hitting ‘the wall’?
来源：未知 作者：苍褙劢 时间：2019-03-01 01:08:02
Keith Larby / Alamy By Aylin Woodward “Bonking” takes on a very different meaning when you start running. It doesn’t matter whether you are a seasoned runner or a newbie, when faced with your first marathon, it is impossible to ignore talk of bonking or “hitting the wall”. It will leave you weak at the knees, but not in a good way. Those who have been through it describe the experience as a sudden onset of debilitating fatigue and loss of energy that happens during the race’s latter half. Formerly speedy runners slow to a shuffle, often capitulating to the need to walk, and a racer swiftly switches from a desire to finish in a certain time to a yearning to just finish at all. Bonking is a surprisingly slippery subject. From a physiological standpoint, we know we hit the wall when we run out of glycogen, a carbohydrate stored in our muscles and liver that provides a readily available source of energy. At this point, the body switches to its fat stores. Fat is a great fuel source because we have loads of it, but we are much less efficient at turning it into energy than carbs. This means runners can’t maintain the intensity they were moving at, and have to drop to a walk. 34km is the point in a marathon where you are most likely to “hit the wall”. Make it this far without a hitch,