Each month iVillage poses a different question to our Dream Team of experts. Here's what we asked this month: Warming up -- do we really need to do it? When and how should we warm up?

Liz Neporent, MA

Warming up is essential to get blood flowing into the exercising muscles and to raise your body temperature so your muscles are more pliable and "ready" to exercise. Scores of studies show that a five-to-ten-minute warm-up consisting of a low-level cardio activity like walking, pedaling a bike or light jogging can prevent injury and improve performance.

What is not essential is the preworkout stretch. In fact, most research shows that stretching before activity increases your chances of injury, decreases workout performance and has no real physical benefits to speak of. The only exception to this is "active stretching" where you do things like circle your arms and shake out your legs as opposed to doing a series of stretches that you hold for 30 seconds or more. Save your slow, static stretching for the end of your workout, after you've cooled down for five to ten minutes in a way that's similar to your warm-up.

Stacy Berman, Trainer

Warming up is an essential part of your workout because it prepares your mind and body for a higher level of exertion. It also decreases your risk of injury by making sure your muscles, tendons and ligaments are elastic enough to function properly.