This is a great way to pump your body fast. It should only be done by experienced trainers; people who have been training regularly for a good amount of time. Lactic acid training is a controversial method of developing muscle and losing weight because if done in excess you can actually decrease your muscles.
When we exercise we are pumping blood into our muscles, and with that comes lactic acid. Most the time we will stretch and strain this out, but with lactic acid training we work to trap as much as we can in our muscles. The reason is when we have lactic acid in our muscles it tells our bodies to create a growth hormone. This growth hormone is going to rapidly speed up protein synthesis and it is also going to tell our bodies to start burning fat and fast.
If you want to trap the lactic acid in your muscles all you need to do is perform fast abduction with slow contraction. So if you are doing a pushup with lactic acid training, you will push up as slowly and as controlled as you can. Try to feel the burn go throughout your entire pectoral muscle. Once you have hit the high point drop back to the ground as fast as you can (without smacking your face on the floor). This will trap the lactic acid in your pectorals and cause increased muscle development.
However, you should not do this more than once a month. The lactic acid can eat away your muscles, thus leaving you a flabby man with soggy pecs, and you don’t want that. One other thing this acid is what makes you feel sore. So the day after you try this exercise you are going to be miserable, I guarantee it.