Begin by laying on your side with knees bent and a foam roller between your knees. If you don’t have a foam roller you can use a thick pillow. Squeeze the the foam roller or pillow with your knees as you pick up your foot toward the ceiling.
Repeat 10x’s, 1-3 sets.
Progress by adding a band around your knees as illustrated below. Start with a yellow (lighter resistance) band.
DISCLAIMER: Please consult a healthcare professional before attempting exercise.