However, such studies have been flawed methodologically, and a new investigation reveals that combining protein with carbohydrate after workouts is not a superior strategy, compared with taking carbs alone.
You've heard them: The "experts" who cite scientific studies to support their contention that post workout protein intake boosts recovery. The internet marketers who rave about their specific blends of amino acids, expensive supplements which are purported to help athletes stay …show more content…
healthy and recover more quickly after strenuous training.
And the athletes who claim that their health problems disappeared and their performances soared after they began using various protein-rich concoctions. Is all this protein fanfare just poppycock, or can post-workout protein supplementation really help you recover more effectively and become a better runner?
At first glance, the strategy of taking in protein immediately after exercise seems to make sense. Think, for example, about situations in which you have gone overboard with your training: When you have carried out too many one-leg squats, completed too much downhill running, or simply run too far during a training session, your muscles let you know about your mistake by producing an incredible amount of post workout soreness and stiffness.
Your recovery from such effort is much-slower than usual, as the discomfort and tightness associated with your excesses may linger for 48 hours or more.
If we looked carefully at your muscle metabolism during such painful, extended recoveries, we would find that one of the key departures from normalcy would reside in your muscles' sudden adoption of a "negative nitrogen balance". That is, your muscles would be breaking down and losing more protein than they were making.
This scenario has caused some exercise scientists to theorize that negative nitrogen balance is the key event which retards recovery. If this is true, swallowing a significant amount of protein after workouts should decrease the possibility of negative nitrogen balance (by providing the basic building blocks for the protein-construction process) and thus increase the likelihood of a quick and effective recovery.
Even in cases when notable muscle soreness and stiffness are not produced, it is known that muscle-protein synthesis can be depressed for several hours after a strenuous workout. When protein is ingested after training sessions, however, protein synthesis tends to increase, and necessary repair operations should be able to proceed more easily within muscle fibers. It seems only logical, then, that post workout protein ingestion might be beneficial for recovery.
One problem with this thinking, however, is that some of the research linking post-workout protein consumption with higher muscle-protein anabolism has involved the simultaneous ingestion of protein and carbohydrate following the workouts. Thus, it is not clear whether the better post workout protein profile was the result of the ingested protein, the taken carbs, or some combination of the two.
Carbs? What do those completely lacking-in-nitrogen compounds have to do with protein creation? As it turns out, carbohydrate ingestion after a workout can have powerful effects on intramuscular protein breakdown and synthesis.
For example, post-workout carbs (without any protein along for the ride) can decrease the rate of protein degradation in muscles and increase whole-body protein creation.
These twin effects are of course highly desirable for athletes, whose performances will generally fall if significant quantities of protein are lost (remember that proteins are the building blocks of muscles and that certain proteins can also serve as energy-releasing enzymes within muscle cells).
How can carbs conserve protein and also boost protein synthesis? For years, exercise scientists have reckoned that the basic mechanism underlying carbohydrate's protein-helping properties is simply that ample carbs give muscles enough energy to stimulate protein production (and also provide enough fuel so that muscles don't need to break down protein to provide basic energy requirements).
However, proteins are made of subunits called amino acids, and the breakdown of a very important group of amino acids called the branched-chain amino acids is regulated by the activity of an enzyme called BCOAD. As you might expect, a diet which is very rich in protein leads to an increase in BCOAD activity in the liver. On the other hand, when athletes step up their carb intakes, BCOAD activity drops. Thus, luxuriant carbohydrate ingestion seems to spare protein by calming down …show more content…
BCOAD.
Thus, we are left with a rather-perplexing situation. Post-workout protein ingestion seems to be able to enhance muscle-protein anabolism, but post training carb intake might heighten protein-building just as well - or even better. This might seem really crazy to you: After all, you may be thinking, where would muscles get the amino acids to build their proteins during recovery if they were not being ingested following exercise? The answer is that muscles have the ability to simply remove the amino acids which are natural constituents of blood plasma. Blood-borne amino acids are always "standing by" for potential use by the muscles.
As another alternative (to the notion that carbs or protein might be better at spurring recovery), some combination of protein and carbs might be the "answer" for speedier recovery.
Making matters even more complicated, actual performance has seldom been measured in the existing recovery research, which has tended to look at rates of protein synthesis and degradation rather than 10-K times. Thus, it might be possible to observe somewhat-better protein building inside muscles following workouts in association with a particular intake of carbs and/or protein, but this enhanced synthesis might not produce any actual change in exercise capacity, which is of course the desired end result.
The true goal of recovery is not just to have neat things happening with your muscle proteins: It is to adapt in such a way that you will be able to perform at a higher level in your workouts and competitions.
In an attempt to sort out the roles played by carbohydrate and protein during recovery, researchers from the Georgia Institute of Technology and Georgia State University recently carried out a unique study with eight runners (five males and three females; average age 29). The athletes were highly trained, with an average best 5-K time of 1006 seconds (16:46) and a weekly training volume of about 98 kilometers (61 miles). Mean VO2max was 56.5 ml.kg-1.min-1, and average percent body fat was just 11.3 percent.
The study had a beautiful, double-blind, cross-over design, and the athletes ingested three different beverages after their workouts, on separate occasions (at least seven days apart). One of the drinks, a carb-protein combo, was 8-percent sucrose and 2.3-percent whey protein isolate, with branched chain amino acids, glutamine, and vitamins E and C.
A second drink, identical in caloric content with the first beverage, was all carbs - with 8-percent sucrose and 2.3-percent maltodextrins. The third quaffable was our old friend, traditional Gatorade, which contains no protein; with its sucrose-glucose composition, Gatorade tips the drink-composition scale at ~ 6.3-percent carbohydrate. The three drinks were similar in color and flavor (the always-popular "fruit punch").
The actual running proceeded as follows: The eight athletes reported to the laboratory in the morning in a fasted state (that is, without having breakfast) and completed a 21-K training run at an intensity of 70 percent of VO2max (about 80 percent of maximal heart rate) on an outdoor course. This 21-K workout was chosen because of its known ability to reduce muscle-glycogen concentrations rather dramatically.
But that was just the beginning point for the runners' rigorous schedules! As soon as they returned to the laboratory following their 21-K runs, the harriers ran on a treadmill at an intensity of 90 percent of VO2max (about 94 percent of maximal heart rate) until a state of volitional fatigue was reached. Recovery then commenced.
The overall quality of recovery was assessed during a 5-K race-completed on the day after a 21-K workout and two runs to exhaustion!
During recovery, the runners consumed the carb-protein drink or - on a separate occasion when the same exercise protocol was utilized - the all-carb beverage in a manner which provided them with 1.0 grams of carbohydrate plus protein - or 1.0 grams of carbohydrate only - per kilogram of body weight per hour (1.0 gram per kilogram of body weight per hour is the current "gold standard" for carb replacement after training sessions have been completed). Please note that the 1.0 grams refer to the amount of carbohydrate ingested or the amount of carb-plus-protein taken in, not the mass of drink. The third drink, the Gatorade, was consumed on a separate occasion in the same volume as the first two potables, but because of its lower carb content the Gatorade provided just 6 grams of carbs per kilogram of runner body weight per hour.
Then, after just two hours, the runners returned to their treadmills to warm up for five minutes, and they then completed another run to volitional exhaustion at 90 percent of VO2max. If the drinks were going to boost recovery, they were going to have to act quickly!
Naturally, the researchers were not only interested in how the runners could perform after two hours of recovery: They also wanted to know what would happen on the following day. So, 24 hours after the end of the 21-K training run, all eight runners reported to a track and completed a 5-K time trial, running as quickly as they possibly could. Muscle soreness was assessed before this 5-K run, and performance times in the 5K were recorded.
As it turned out, the 21-K workout was completed in an average time of 89 minutes. Blood glucose was higher 45 minutes after the completion of the 21K and the first treadmill run to volitional exhaustion when the high-carb concoction was used during recovery, compared with the carb-protein mix and the Gatorade. However, during the second hour of recovery there were no blood-sugar differences between the three groups (note that the drinks were provided right after the first run to volitional exhaustion and again after one hour of recovery - two times in all).
But - I am sure you are more interested in how the athletes actually performed, compared with the levels of carbs in their bloodstreams, and I'm with you. During the second run to volitional fatigue at 90 percent of VO2max (remember that the first of these runs occurred right after the 21-K effort and the second took place two hours after the first), the carb-protein and Gatorade drinkers fared 41 percent better on the second test, compared with the first, and the all-carb guzzlers were 30-percent better.
However, these results were not significantly different.
A similar situation prevailed during the 5-K time trial on the following day, with 5-K times being almost exactly the same for carb recovery, carb protein recovery, and Gatorade restoration!
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