Lie on your front with a weight around your affected ankle, and bend both knees.
Lift your body up onto your forearms, ensuring your elbows are under your shoulders.
There should only be a slight angle at your hips.
Holding this position, lift the knee of your affected leg off the floor, pushing the sole of your foot up towards the ceiling.
Hold this position before you lower it back down to the starting position, and then repeat.