Yup you shouldn't stretch before a work out in the discipline of weight lifting. The research shows that you'll be weaker and from what I've read this is basically that stretching a muscle releases tension to help the muscle and connective tissue (fascia etc) relax. You don't want this before lifting weights, furthermore you'll have a greater chance of injury and also you'll be weaker in your lifts. This is for static stretching.
Didn't know about this, thanks.