3 oktober 2012 kl 12:37
Redigerad 3 oktober 2012 kl 12:37
Refueling The Tank
What your athletes eat and drink immediately after a workout or game can affect their next performance—for better or worse. The key is to quickly restore to the body those important nutrients it just lost.
By Leslie Bonci
Leslie Bonci, MPH, RD, is Director of the Sports Medicine Nutrition Program at the University of Pittsburgh Medical Center Health System. She is also a consultant to the Pittsburgh Steelers, the University of Pittsburgh Athletic Department, and several high schools in the Pittsburgh area.
Coaching Management, 9.2, March 2001,
http://www.momentummedia.com/articles/cm/cm0902/refueltank.htm "Replacing Glycogen
The other important component of post-exercise refueling is replenishing glycogen stores. Restoring muscle and liver glycogen stores following strenuous training will minimize the fatigue that results from repeated days of heavy training.
Muscles replace glycogen at a rate of five percent per hour, so it takes 20 to 24 hours post-exercise for the body to replenish muscle glycogen stores maximally. However, muscles are most receptive to fuel within 15 minutes after exercise, when the blood flow to the muscles is still very high and the enzymes that produce glycogen are most active. In fact, the lower the muscle glycogen stores at this time, the faster the rate of recovery. Therefore, a delay in intake of post-exercise fuel will slow the recovery rate.
The best way to restore glycogen levels is by consuming adequate amounts of carbohydrate. The goal is to drink and/or eat at least 50 grams of carbohydrate as soon as possible post-exercise.
Despite what many advertisements tout, there is no benefit to a low-carbohydrate/high protein diet for an athlete, as it can contribute to chronic fatigue, slower recovery, and increased risk of injury. Over and over, research has shown that the body cannot efficiently replenish muscle glycogen without carbohydrates.
However, there may be a role for small amounts of protein in post-exercise recovery. Some studies have suggested that a mix of carbohydrate and protein in a 3:1 ratio post-exercise may replenish muscle glycogen more rapidly and promote muscle tissue repair. The idea is that adding protein to the post-exercise fuel results in a greater secretion of insulin than carbohydrate (or protein) alone, and the release of insulin may stimulate muscle growth.
It’s also important to consume the “right” type of carbohydrates, namely those with a moderate-to-high glycemic index. A food’s glycemic index indicates its ability to raise blood glucose, which may enhance the replenishment of muscle-glycogen stores post-exercise. Some examples of foods with a high-glycemic index are potatoes, honey, cereal, corn chips, white bread, jelly beans, and high-carbohydrate sports drinks. Moderate glycemic index choices include cookies, bagels, crackers, wheat bread, ice cream, and potato chips.
When it comes to choosing liquids versus solids for effectiveness and absorption of carbohydrates, either is fine. Liquid and solid carbohydrate-rich foods of comparable carbohydrate content will result in a similar rate of glycogen resynthesis. Many fruits provide both carbohydrate and fluid and thus can be used to satisfy rehydration and glycogen repletion simultaneously. Good choices include grapes, blueberries, apples, peaches, celery, strawberries, melon, tomatoes, oranges, and cherries.
To make things a little confusing, though, one drawback to eating fruit is that it contains fructose. And some research shows that carbohydrate-rich foods containing glucose or sucrose may be twice as effective as those containing fructose in restoring muscle glycogen post-exercise. This is because fructose is converted to liver glycogen, whereas glucose is converted to muscle glycogen.
The bottom line: advise an athlete to include a variety of carbohydrates post-exercise. For example, even though fruit contains fructose, it can be very refreshing and provides fluid to aid in rehydration. So, encouraging consumption of a piece of fruit with another carbohydrate-rich food, such as a bagel or handful of sweetened cereal, will encourage both fluid repletion and glycogen resynthesis. Athletes should also be encouraged to experiment with these foods for taste preference, tolerability, and effect. They can record what foods work best, then make sure to have them available.
Beyond immediate post-exercise consumption, athletes should eat a carbohydrate-rich meal two hours post-exercise. They should then continue to consume carbohydrates throughout the next 24 hours (or before the next workout or game).
The maximum level of carbohydrate intake seems to be 500 to 700 grams a day, above which one will get little, if any, added contribution to glycogen storage or improvement in athletic performance. "
Enligt sista stycket så verkar det som att man inte kan tanka mer än 500-700gram per dag.
