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Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "
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03.09.2012 |
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Leucine is not a panacea
Leucine is an interesting amino acid that boosts the anabolic effect of proteins. Nevertheless, a shake containing 25 g whey isolate still works better than a shake containing 6 g whey plus a spoonful of leucine powder, sports scientists at McMaster University in Canada discovered.
The researchers did a trial using 24 male students, average age of 22. The students first had to do four to-failure sets of 10-12 reps on the leg press, and another four similar sets on the leg extension machine. The students only did the exercises with one leg, and immediately afterwards they drank a shake.
One group of eight students were given a shake containing 25 g whey isolate [Whey]. The 25 g whey contained 3 g leucine.
A second group of eight students were given a shake containing 6.25 g whey isolate to which the researchers had added a couple of grams of leucine so that these students also consumed 3 g leucine [Leu].
The researchers then took biopsies over a period of five hours so that they could measure the synthesis of muscle proteins [FSR] in the students' legs. The figures below show that the three shakes all worked equally well in the non-trained leg [Fed], but that 3-5 hours after intake whey performed better in the trained leg [Fed-Ex].
The figures above show the effects that the shakes had on anabolic signal molecules such as mTOR and p70S6K. You can see that 25 g whey has more effect than the whey-amino acid mixes.
"Only whey, containing both essential amino acids and non-essential amino acids, was able to sustain the elevated rates of muscle protein synthesis 3–5 hours after resistance exercise and therefore may be a better choice to support resistance exercise induced anabolism", the researchers conclude.
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