Working muscles generate energy anaerobically. This energy comes from glucose through a process called glycolysis, in which glucose is broken down or metabolized into a substance called pyruvate through a series of steps. When the body has plenty of oxygen, pyruvate is shuttled to an aerobic pathway to be further broken down for more energy. But when oxygen is limited, the body temporarily converts pyruvate into a substance called lactate, which allows glucose breakdown--and thus energy production--to continue. The working muscle cells can continue this type of anaerobic energy production at high rates for one to three minutes, during which time lactate can accumulate to high levels.

About 30-45 min before your workout take a whey protein shake and some "no-explode" supplements. This will reduce your soreness. And dont try to be Tony Horton in the first week. Those videos are 50-60 min. My first week i was crying at 35 min.

After your workout try a recovery drink with amino acids (especially beta-Alanine and Glutamine). L-cartatine is great for pre workout too.

Good luck
Glenn

Yes, it does get better. Finished my second round of P90X and I was sore like you the first few weeks. Stick with it!!

Completely agree with all of the above. Whey is Way Way Wonderful