Sit upright on a stool so that your hips are higher than your knees.
Bring your buttocks to the edge of the stool.
Lift your unaffected foot off the ground and keep it in front of you.
Try to do this exercise without using your hands.
Keeping your affected knee in line with your toes, stand up by leaning your body forward and pushing down through your foot until you are completely upright.
Hold this position.
Control the movement as you sit back down and then repeat.