發表於 2007-12-5 09:32:02
I dont agree with yours (cardio not working hard enough to support muscles sounds more like the lack of warm up to me?). I believe the below is more appropriate.|
Glycogen and “the wall”
Carbohydrates that a person eats are converted by the liver and muscles into glycogen for storage. Glycogen burns quickly to provide quick energy. Runners can store about 8 MJ or 2,000 kcalworth of glycogen in their bodies, enough for about 30 km or 18-20miles of running. Many runners report that running becomes noticeably more difficult at that point. When glycogen runs low, the body must then burn stored fat for energy, which does not burn as readily. When this happens, the runner will experience dramatic fatigue. This phenomenon is called "hitting the wall". The aim of training for the marathon, according to many coaches,is to maximize the limited glycogen available so that the fatigue ofthe "wall" is not as dramatic. This is in part accomplished byutilizing a higher percentage of energy from burned fat even during theearly phase of the race, thus conserving glycogen.
Carbohydrate-based "energy" gels are a good way to avoid or reducethe effect of "hitting the wall" as they provide easy to digest energyduring the run. Some people recommend taking an energy gel every 45-60minutes during the race. Energy gels usually contain varying amounts ofsodium and potassium and some also contain caffeine. They need to beconsumed with a certain amount of water.
Alternatives to gels are solid candy, cookies, other forms ofconcentrated sugars, or any food high in simple carbohydrates which canbe digested easily by the individual runner.
Many runners experiment with consuming energy supplements duringtraining runs to determine what works best for them. Each runner may bedifferent.
[ 本帖最後由 kaevin 於 2007-12-5 09:33 編輯 ]