The most common affect that is uttered, usually by people who have not read a book on physiology in the last 30 years, is that it is the cause of muscle soreness.
It is not the cause, in fact, if it did contribute to soreness, it would at the end of the list.
The main cause is from micro trauma to the muscle tissue itself.
You see, when the level of training exceeds the contractile strength of the tissue, tiny tears occur in the muscle.
When this happens, there is an inflammatory effect and the body sends out chemicals (bradykinin and prostaglandins)to cause sensitivity to the nerves endings.
These two things together cause that familiar pain that every athlete is intimately aware of. Simply stated, Lactic Acid is the by product of anaerobic (without oxygen) metabolism.
It is the one of the main limiting factors in how hard we can push during intense exercise.
As it builds up in the muscles, it directly interferes with the muscles ability to contract and when it reaches a certain threshold, muscle failure occurs.
This is a beautiful safety mechanism because if were not there, we would be able to keep pushing until something snaps or breaks.
The body is designed perfectly to keep increasing it's ability to do more and more but it is also wise to listen to it when it tells you when you have had enough.
Push into that familiar burn, it won't kill you, however, It is a good idea for beginning athletes to find out where that threshold is early on, those who don't find out that puking is just past the point they should have stopped.
The more you train, the better you learn how to dance at that threshold to help accelerate you power, strength, and speed.
I will get into topics like anaerobic threshold in later more detailed articles.
This one was just to clear up some misconceptions, so if you are in a conversation and you here someone say that they are sore from Lactic Acid, either let them know what you learned here, or just smile.
Here is to all your success now and in the future and check back often for more information.