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In response to
"Since I am not around a lot..is there anyone left here that is a true fitness expert that could maybe answer a question about enhancing muscle "
by
Capstern
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Muscle recovery for bicyclists
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Finally, take advantage of the glycogen repletion window that is open in the 4 hours immediately following vigorous exercise. During this time, any carbohydrates you eat will be converted into muscle glycogen at 3 times the normal rate - and some data suggests there is a 50% fall in this super charged repletion rate by 2 hours with a return to a normal repletion rate by 4 hours. (Ivy JL et al,J Appl Physiol 1988 Apr;64(4):1480-5). The slowing rate of glycogen storage occurs even when plasma glucose and insulin levels remain elevated with oral supplements. It has been suggested that the initial elevated replacement rate is insulin independent, while the slowing at 4 hours is a shift to the normal insulin supported muscle cell absorption rate.
After this initial 4 hours, muscle glycogen stores are replenished at a rate of approximately 5% per hour. And while it may require up to 48 hours for complete muscle glycogen replacement following a 2 hour ride, for all practical purposes glycogen stores are almost completely rebuilt in the first 24 hours post event. But for the athlete who is on a daily training schedule, or is in a multiday event, the glycogen window can be used to get a jump on the normal repletion process and minimize the chance of gradually developing chronic glycogen depletion (and the fatigue that goes along with it).
* How much glucose is enough during this 4 hour interval? Most studies have suggested that you can incorporate 3 grams of carbohydrate per kg of body weight during this 4 hours and up to 10 grams per kg over the post ride 24 hour period.
* Is more better? Although the rate of CHO incorporation begins to fall at 2 hours, taking all the CHO in the first few hours may not be the answer as there appears to be a maximum repletion rate in the neighborhood of 1.5 grams of CHO per kg body weight per 2 hour period.
* Is the type of carbohydrate important? Glucose and sucrose appear to be of equal value while there is some evidence that fructose is less beneficial.
* Will the addition of protein to a carbohydrate drink facilitate glycogen repletion during this glycogen window (compared to a pure glucose drink alone)? Although it had been originally been suggested in 1992 that the addition of protein to a carbohydrate supplement would enhance the rate of muscle glycogen resynthesis after endurance exercise (Zawadzki et al., J. Appl.Physiol. 72: 1854-1859, 1992), Roy et al (J Appl Physiol 1998 Mar;84(3):890-6) provided evidence that the difference was not protein per se, but the fact that the two drinks were not Calorically equal. Van Hall (J Appl Physiol 2000 May;88(5):1631-6) also supported that finding when they demonstrated the failure of the co-ingestion of carbohydrate and protein, compared with ingestion of carbohydrate alone, to increase leg glucose uptake or glycogen resynthesis rate further when carbohydrate was ingested in sufficient amounts every 15 min to induce an optimal rate of glycogen resynthesis.
But the latest study, done in runners, looked at the ultimate test - performance itself. This study did demonstrate an improvement in a second run, done the same day (not 24 hours later) with a post event CHO-Protein supplement versus CHO alone. What can we make of these studies?
o Protein Calories cannot replace CHO Calories, so don't skimp.
o Protein added to a calorically adequate CHO drink appears to promote early glycogen replacement and support repetitive performance - especially if the 2nd event will occur less than 24 hours after the first.
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