"Most athletes see lactic acid as their enemy, and think that training helps them eliminate the metabolic waste product from their muscles so they will function longer and harder. But UC Berkeley physiologist George Brooks has found that training actually teaches your muscle cells how to use lactic acid as a fuel source to get more bang for the buck."
Taku and harry arent missing the point. Biologists have known that lactic acid is used to generate energy for a long time now. It is, however, dramatically innefficient at doing so, and is a "last ditch" effort at producing energy before you run out completely. Increasing lactic acid levels in the body signal fatigue and not only the end of your energy supply, but also a change in your pH significant enough to reduce the effectiveness of your basic functions.
So sure, training to produce lactic acid might help your body to be better able to use it as an energy source. Awesome. If you had asked me this years ago i would have guessed rightly. In fact, your body will use any of its energy systems more efficiently through training. To that revelation we can all say: "No shit sherlock."
After a quick look through some resources, i found the following:
Per molecule of glucose you produce 38 molecules of Adenosine TriPhosphate (ATP).
I can't find the results for Lactic acid, but its something like 1 or 2 molecules of ATP per molecule of lactic acid, if memory serves. Also, during its utilization it strips NADH of electrons, and creates no further useful byproduct.
Again, this is nothing new, accept maybe that they have confirmed ("ne shit sherlock") that training will improve its efficiency. This doesnt mean that the lactic acid will produce more ATP. No, it means that you might use 10% of the produced lactic acid for energy instead of 9%. Incidentally, you will also be able to buffer it quicker, and return quicker to a more preferable state in which glucose is used for fuel.