Running is a great workout, but it can also be tough on your joints, especially if you aren’t diligent about warming up before a run and cooling down after. In fact, if you find yourself skipping the stretches postrun, you may notice pain on the outside of your knee, sometimes referred to as runner’s knee. This pain often stems from the iliotibial (IT) band.
“The IT band is a tissue that runs along the side of your leg,” Dania Valdes, an ACE-certified personal trainer and fitness specialist at Mindbody, told POPSUGAR. “It links the hip joint to the knee joint and helps stabilize the knee as the gluteus maximus, a prime mover for hip extension, is engaged when running.” Overtraining, not stretching properly, and even wearing the wrong type of running shoes can all cause the IT band to become tight or inflamed.
Prevent the pain by doing these IT band-focused stretches after a run to help release tension. If you want to improve or maintain flexibility, Valdes recommends doing them before your run, too.
Source: Pop Sugar