This mobility exercise is awesome for releasing tightness in the glute muscles, a common area of restriction that can contribute to hip, knee and low back pain.
Start by lying your outer glute muscle on an Acumobility ball. This is a 45-degree side-lying position. Create stability by engaging the lat muscle, the opposite glute, and foot. The bottom leg should then raise off the ground in a clamshell position trying to reach the top knee. Make sure the top knee does not move. Find 3 trigger points in the glute and do 8 reps on each. Then move into the knee drive position where you bring your knee to chest and then into full extension. Repeat 8 reps on each spot.