Stretching is a beneficial and important part of staying healthy. Stretching properly increases your flexibility and helps protect you against injury, but you have to do it in the right way and at the right time. For a long time, stretching before exercising was the thing to do, but now stretching after exercising is seen as correct. But are there any times when stretching before is good? Really, there's only one time. All other information points to stretching after.
You Like It
The major reason to keep stretching before you exercise is that you like it. If it makes you feel better, go for it; just be aware of the downsides so you can accommodate.
But It Affects Your Warm-Up
Sparkpeople points out a major flaw in stretching before exercising: it ruins your warm-up routine. You've just warmed up and gotten ready to move, and now you're nearly stationary, trying to stretch your arm or leg. All that warm-up is going out the window, and you're cooling down as you stretch. When you finally start exercising, you're not going be as warmed up as you should be. You'd basically have to warm up, stretch, and warm up again to counter this effect.
You Might Not Be Getting Full Benefits
Stretching after warming up but before exercising might not be as beneficial as stretching after exercising because a warm-up doesn't really get you as warm and pliable as your full exercise routine. So you might be getting some benefit from the stretching, but you wouldn't get the full benefit that you might have gotten had you waited to stretch until later.
It May Make You Perform Worse
Boston University reports that stretching before you work out could possibly make you worse at whatever activity you're doing. You might not run as fast or as far, for example. Obviously, with so many people stretching before a workout for many years—remember, this was the traditional advice—it's not the worst activity in the world. But if you're really trying to do your best at whatever activity you're attempting, then the small but apparently significant drop in performance would not be welcome.
If you're still concerned that not stretching before you exercise will somehow affect you negatively, talk to a sports doctor, such as one from Interior Alaska Orthopedic & Sports Medicine, about the best way to structure your workout or sports routine. He or she can help you figure out the best moves and the best timing.