1

Start lying on your back with your legs fully extended, heels on the wall.

2

Bringing the ankle of your uninjured leg under the ankle of your injured leg, slide your feet down the wall to either the point where your knee gets to stiff or uncomfortable to go any further., Use the uninjured leg leg to gently raise your leg back to full extension.

3

If you have a hard time getting up and down off the ground, you can also do this movement on a raised surface like a bed or massage table.