8 Best Exercises to Help With ACL Rehabilitation

Exercises aimed to improve strength and range of motion

The anterior cruciate ligament (ACL) is a ligament in the middle of the knee. Ligaments are thick bands of tissue that connect your bones to each other. The ACL prevents the shin bone from sliding out in front of the thigh bone.

An ACL injury is caused by overstretching or tearing this ligament. The tear may be either partial or complete.

Physical therapist examining patient - stock photo

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An injury to the ACL affects the stability of your knee. This can result in loss of leg strength and a restriction in the knee's range of motion.

Severe tears or ruptures will often require surgery. You may need extensive rehabilitation to fully restore your mobility.

This article provides instructions for performing exercises that will aid in your recovery from an ACL injury.

At-Home Rehabilitation for ACL Injuries

These at-home exercises can help you recover from an ACL injury. Doing these exercises can help you regain strength and movement without causing further injury to the ACL.

It is important to avoid exercise that compresses or puts weight on your knee. Instead, the focus should be on strengthening the muscles surrounding the knee.

These muscles include the quadriceps muscles ("quads") in the front of your leg and the hamstrings ("hams") in the back part of your thigh. Strengthening these muscles will help you gradually extend your range of motion so your knee doesn't "freeze."

These exercises can be done at home, ideally with the input of your doctor or physical therapist. They can help prepare you for ACL surgery, or complement your structured rehabilitation program.

Safest ACL Rehab Exercises to Start

Here are three of the best and safest exercises for an ACL injury. Do these exercises early on, when your knee is still fragile.

Heel Slides

This exercise extends the knee without bearing any weight.

  1. Start by sitting on the floor with your legs outstretched.
  2. Slowly bend the injured knee while sliding your heel across the floor toward you. Slowly slide the foot back into the starting position.
  3. Repeat 10 times.

Isometric Quad Contractions

This exercise is also done while seated.

  1. Sit on the floor with your injured leg extended and your other leg bent.
  2. Slowly contract the quadriceps of the injured knee without moving the leg. The quadriceps are the muscles on the front of your thigh.
  3. Hold for 10 seconds.
  4. Relax.
  5. Repeat 10 times.

Prone Knee Flexion

This exercise is performed while lying on your stomach.

  1. Lie on your stomach with your legs straight.
  2. Bend your injured knee and bring your heel toward your buttocks.
  3. Hold 5 seconds.
  4. Relax.
  5. Repeat 10 times.

When first starting, forget the adage "no pain, no gain." You will probably feel discomfort when exercising the quads and hams, but stop if a movement causes outright pain. Pushing too hard can make your injury worse and may result in lengthier recovery time.

ACL Exercises When Swelling Subsides

As the swelling goes down, you should gradually be able to stand squarely on both feet without favoring the uninjured leg. When you can do this, you can start doing the following exercises.

Passive Knee Extensions

This exercise requires two chairs of equal height. Place the chairs facing each other. The distance between them should be slightly shorter than the length of your leg.

  1. Sit in one chair and place your heel on the seat of the other.
  2. Relax your leg and let your knee straighten.
  3. Rest in this position for 1 to 2 minutes several times a day. This will gradually stretch out your hamstrings.

Heel Raises

This exercise is done while standing.

  1. Start by placing one hand on the back of a chair for balance.
  2. Now slowly lift your heels, standing on your tiptoes.
  3. Stay there for 5 to 10 seconds.
  4. Slowly lower your heels.
  5. Repeat 10 times.

Half Squats

This exercise is done standing while holding a sturdy table with both hands.

  1. Place your feet shoulders' width apart. Slowly bend your knees and lower your hips into a half squat.
  2. Hold for 10 seconds and then slowly return to a standing position.
  3. Repeat 10 times.

Knee Extensions

This exercise requires either a TheraBand or a length of an exercise band.

  1. To begin, loop one end of the band around the leg of a sturdy table. Loop the other end around the ankle of your injured leg. Alternately, tie both ends of the band around the table leg and insert the ankle of your injured leg into the loop.
  2. Facing the table, slowly bend your knee about 45 degrees against the resistance of the tubing.
  3. Hold for a few seconds and slowly return to a standing position.
  4. Repeat 10 times.

Standing on One Leg

Standing on one leg is a great way to test and build your strength and balance.

  1. Stand on both feet.
  2. Lift the uninjured leg and stand unassisted on the injured leg for 10 seconds.

This exercise may not be easy at first. With time and patience, though, it should become easier.

Recap

Do these exercises once the swelling subsides and you can comfortably stand on both legs.

Summary

An ACL injury happens when you overstretch or tear the ACL ligament in the knee. You may need surgery or extensive rehabilitation to recover from this injury.

Exercises you can do at home can help you while you wait for surgery or work on your rehabilitation. Start with the safest exercises and avoid compressing or putting weight on your injured knee.

After the swelling subsides, you can try exercises that are done while standing on both legs.

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3 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. Duncan KJ, Chopp-Hurley JN, Maly MR. A systematic review to evaluate exercise for anterior cruciate ligament injuries: does this approach reduce the incidence of knee osteoarthritisOpen Access Rheumatol. 2016;8:1-16. doi:10.2147/OARRR.S81673

  2. Begalle RL, Distefano LJ, Blackburn T, Padua DA. Quadriceps and hamstrings coactivation during common therapeutic exercisesJ Athl Train. 2012;47(4):396-405. doi:10.4085/1062-6050-47.4.01

  3. Manske RC, Prohaska D, Lucas B. Recent advances following anterior cruciate ligament reconstruction: rehabilitation perspectives: critical reviews in rehabilitation medicineCurr Rev Musculoskelet Med. 2012;5(1):59-71. doi:10.1007/s12178-011-9109-4

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