When to do it
Use a foam roll after your training session or after you've been in the same position for hours, such as after sitting on a plane or behind a desk.

How it works
Imagine your muscle as a shoelace. It has a certain length to it. If it gets in a knot and you pull both ends of the shoestring, the knot gets tighter. You need to work the knot out with your fingers to restore the original length of the shoelace. The same goes for our muscles. Sometimes stretching is not what we need. We need to work out those "knots" in the muscle, which often arise from inactivity or repetitive activity, in order to restore the muscle to its original length. This can certainly be uncomfortable, even very uncomfortable.

Roll this way
Glide your body over the foam roll, pausing at any tender points for 10-30 seconds. Only go as deep as you can tolerate and build up the amount of time you spend foam rolling. Your muscle tissue will begin to get used to this new sensation and be more more willing to accept the new form of self massage that you've implemented into your routine.

Push through the discomfort of the foam roll exercises, and you will be doing your body a great favor by reducing your risk of injury and allowing for optimum movement.