i stretch a little between sets and go through a 20-25 minute stretching routine after the workout. thats funny i was just thinking about stretching. some dancer chick helped me stretch today, cause i sure as hell dont know what i am doing.
I had always been taught that stretching keeps the blood flowing and helps prevent against cramps and sore muscles. Your muscles may end up sore anyway, but stretching helps it be not as bad as it could be.
I found this to be true in high school when playing sports. I would imagine it would be the same for bodybuilding.
stretching has helped me feel loose before going to the next set. It also helps bring more blood to the muscle and takes the lactic acid out quicker. I do not feel as sore the next day if I stretch quite a bit during my workout. If I don't then I am really tight and have a hard time getting the muscles to loosen up again. Just my experiences.