Squabbin said:
Just curious as to why you'de say that, i routinely do light stretching b4 my back routine as well as some light warming up on the bike to get some blood flowing. Where did you hear that stretching before deadlifts was bad? I'm frequently on several weightlifting/Bodybuilding forums and i've never heard this before...
Warmup is good. Dynamic stretching is good. Static stretching before a heavy exercise is not good.
The reason for this is that when you use any sort of static stretch on a muscle (be it relaxed passive stretching, isometric stretching, PNF, or something else), there is a decrease in coordination between your nervous system and the said muscle. This comes with a decrease in maximum power output of the affected muscle. In other words, if you stretch a muscle out, for the next hour at least, your maximum power output is reduced. Needless to say, this can lead to injuries.
There are scientific studies which measured this and are referenced by Tom Kurz, Pavel Tsatsouline and others. It is for this reason that nobody recommends static stretching (in the classic understanding of the word) before and during martial arts workouts. It is better to warm up and do dynamic stretches before the workout and stretch statically AFTER the workout, with plans to increase your flexibility in the longer run.
Now, I don't know what you mean exactly by "stretching". You may not mean the proper 20 minute push-yourself-and-grunt-through-the-pain thing many people consider stretching. If you just mean moving around a bit without keeping any given position for too long, then that should be fine. You know, lean down, touch the ground sort of thing, without keeping it for a long time, that shouldn't affect you much.
As for stretching before a hard physical exertion, it should be done in a dynamic fashion, and serve as a warmup. That's why I recommend stuff like pull-throughs. After a couple of sets of pull-throughs with a lighter weight, you will reach your desired range of motion much better than by stretching, and will warm up the relevant muscles in the process.