Stretching is great, but always warm up the muscles first. It's never a good idea to stretch cold. The analogy I use when training a client is to imagine putting a rubber band in the fridge then stretching it. It breaks. I know it's an extreme but you get the idea.
How do you warm your mucles up with out stretching first,maybe a long walk?i always thought thats how you warmed your mucles up by stretching first,thats what i been doing for a long time in the gym,i would strecth first then lift weights,that rubber band story sounds very real!