The prone hang is a pretty simple exercise that can be done at home or in the PT clinic. Be sure to check with your doctor or physical therapist before starting this, or any other exercise.
To do the prone hang, simply lie on your stomach on a bed. Then slowly slide down so your legs are hanging off the edge of the bed. Place a small rolled up towel under your thigh to keep your kneecap from getting squished. Let gravity gently pull your knee into extension, and remain in that position for 30-60 seconds. A small cuff weight placed on your leg can add a little more pressure and pull your knee into more extension.
While performing the prone hang, you may feel a slight pulling sensation in the back of your knee. This is normal. If you feel any sharp pain in your knee, you should stop and check in with your physical therapist.
If you have had knee surgery and are trying to gain knee extension ROM, then the prone knee hang may be for you. Give it a try and let us know how it worked out.