Researchers have found that it is a good idea to break up your normal training routine with a different sport as it avoids repetitive strain injuries and increases the strength of joints and muscles.

Swimming is an excellent cross-training activity for running because it's not weight-bearing, so it gives your joints (which take a lot of stress when you're running) a break.

Wear and tear on facet joints in the lower spine causes the cartilage between the two bony sides of the facet joints to break down.