Prone Hang Exercise to Improve Knee Extension Range of Motion

The prone hang exercise is a simple method to use to help improve your knee extension range of motion (ROM) after injury or surgery. Knee extension refers to your knee's ability to straighten out all the way.

An exercise to help increase range of motion
Brett Sears, PT, 2013

A common problem after knee surgery is a loss of knee ROM in both flexion (bending) and extension. Exercises to improve knee ROM can be performed daily after knee surgery. Full knee ROM can help you perform basic functional tasks like sitting in a chair, walking, and climbing, and descending stairs.

Who Should Perform the Prone Hang?

You may wish to do the prone hang exercise if you have any condition that results in a loss of knee range of motion. Common problems that may result in a loss of knee extension ROM include:

Your prone hang exercise may be a part of your post-op knee rehab, or your PT may prescribe it for you to do at home as part of a home exercise program.

If you have had knee surgery or injury and notice that you are unable to fully straighten your knee, you may benefit from performing the prone hang exercise. Be sure to check with your healthcare provider or physical therapist before starting this, or any other, exercise program to ensure that it is safe for your specific condition.

Performing the Prone Hang Exercise

Performing the prone hang exercise is simple to do at home or in the physical therapy clinic.

  • Locate a bed that has at least one side with ample amount of room around it.
  • Lie on the bed on your stomach.
  • Slide down on the bed to the edge so your leg is hanging over the end. Your thigh should be supported on the bed, but your lower leg should be hanging off the bed.
  • Place a small rolled-up towel underneath your thigh just above your kneecap. This helps to keep from placing too much pressure on your kneecap.
  • Remain in this position for 30 to 60 seconds. Allow gravity to pull your lower leg down towards the floor so your knee straightens out.
  • You may feel some discomfort in this position. If you feel intense knee pain, stop the exercise and contact your healthcare provider or physical therapist. You may need to find alternative ways to improve your knee ROM.
  • You can repeat this exercise for five to 10 repetitions. Simply bend your knee to take some pressure off of your leg, and then return to the straight knee position once again. If you have difficulty bending your knee, you can have a friend or family member gently bend it for you.

Sometimes gravity alone is not enough to fully straighten your knee. If this is the case, you can place a one or two-pound cuff weight around your lower leg or ankle to add a bit of force to the exercise. Use caution; too much weight could over-stress your knee. Add just enough weight to create a gentle stretching feeling. Your PT can help you determine the right amount of weight to add.

After performing the prone hang exercise, your knee may be a little sore. This soreness is natural since you are stretching tissues around your knee. Applying an ice pack to your knee for 10 to 15 minutes may help alleviate some of this soreness. Again, if you feel pain in your knee, contact your healthcare provider or physical therapist.

The prone hang exercise can be performed several times a day to work on improving your knee extension ROM. It is a simple yet effective method to help get your knee straight to improve your overall function related to walking, sitting and standing, and navigating stairs.

Don't Cheat

Sometimes pain in your knee prevents you from relaxing fully during the prone hang exercise. Compensatory movements or positions may arise that take the stretch off your posterior knee. The most common compensation movement to watch for is hiking your pelvis and hip off the bed during the stretch. If you are lying face down and your pelvis and hip are rising off the bed, you are simply compensating and removing the stretch from your knee. Be sure to stay as flat as possible during the prone hang stretch.

A Word From Verywell

Achieving full knee ROM after an injury or surgery is often one of the primary goals of PT. Some folks struggle to gain full extension after surgery or injury. That's where to prone hang comes in. If you have had knee surgery and are experiencing a loss of ROM into extension, give the prone hang exercise a try. It may be what you need to help improve your overall knee mobility.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Jiang C, Lou J, Qian W, Ye C, Zhu S. Impact of flexion versus extension of knee position on outcomes after total knee arthroplasty: a meta-analysis. Arch Orthop Trauma Surg. 2017;137(2):257-265. doi: 10.1007/s00402-016-2613-7

  2. Shah N. Increasing knee range of motion using a unique sustained method. N Am J Sports Phys Ther. 2008;3(2):110-3.

Additional Reading

By Brett Sears, PT
Brett Sears, PT, MDT, is a physical therapist with over 20 years of experience in orthopedic and hospital-based therapy.