Iktome said:
I'm pretty sure that's not quite all of it.
Lactate is indeed an energy source, but not in the muscles that you are using at that moment to produce near- or above-sustainable power. Once the lactate gets into the blood, it will be used by various organs and non-working skeletal muscle.
I don't think this is true. With all due respect.
The pyruvic acid combines with ammonia to form the protein alanine. Alanine is then trnsported to the liver, where it can be converted to glucose and stored as glycogen or poured back into bloodstream and carried to the muscles to be used or energy. (Weicker et al.)
Glucose-alanine cycles has been estimated to supply between 10 and 15 percent of the total energy requirement during training (McArdle, Katch, & Katch)
Studies suggest that the conversion of glucose to alanine is a trainable response.
Brooks and Fahey (1984) reported an increased use of alanine after training. Activity of the major enyme that regulates this reaction, alanine tranaminase, was also found to increase with training (Mole, Baldwin, Terjung, & Holloszy).
(Sorry, no link, that is printed documentation)
In my opinion, this is lactate utilisation, aimed at providing energy, for the whole body, not just inactive muscles.
*edit* It is interesting that this is
not a new concept. It has been outlined in scientific litterature back in late '70s I think. At that point, lactic acid was believed by many, to be the cause of acidosis.