So you’ve messed up your ACL.
A painful injury, for sure, but at least you’re not alone. Every year, nearly a quarter of a million people in the U.S. and Canada injure their ACL (full name anterior cruciate ligament—try saying that after a couple of beers). Let’s take a look at why these types of injuries happen and some ACL rehab exercises to help you through recovery.
Why It Hurts You
Before we get to the dos and don’ts of rehab for your busted ACL, let’s talk about how and why these injuries happen. The ACL is one of two ligaments that support the knee. A ligament is a band of tissue that connects bones, joints, and organs to hold them in place, and the human body has more than 900 ligaments in total. Human knees are very flexible compared to other mammals’ knees, but that flexibility also makes them easy to injure. Every time you take a step, you’re also putting about one-and-a-half times your body weight on one leg.
The ACL is right in the middle of your knee and helps rotate the knee and move your shin bone forward when you walk or run. Putting one-and-a-half times your body weight on one leg and changing direction or stopping is a recipe for an ACL injury.i, This is why athletes overstretch or tear their ACLs so often. But no one who has knees and uses them to walk is immune.
If you hurt your knee and:
- You can’t walk or move your leg
- you hear clicking, popping, or grinding when you move the knee
- you can’t stand on the knee or if it feels weak
- you can’t fully bend or straighten your knee,
you may have an ACL injury. It’s a good idea to see your doctor first; the ACL might just be overstretched, but it could also be torn or completely detached from the bone. If it’s partly or fully torn, surgery could be in your future.
Here’s “The Deal”
Every athlete—from part-timers to pros—wants to recover as quickly as possible, but it’s important to have patience while your body heals. Whether you end up having surgery or not, chances are you’ll need to do some ACL rehab exercises to heal and strengthen your ACL. Follow your doctor or physical therapist’s instructions, but you should avoid these three things:
Going Heavy
Early in the recovery process, and possibly right after surgery, a doctor or physical therapist might ask you to put a little weight on the knee. The key here is a little. If you try to walk or run right out of the gate like you did before the surgery, you might mess up your ACL all over again. You can use crutches to keep weight off until your doctor clears you for more exercise, and they might give you a brace to keep your knee stable as you heal.
Cane = Gain
As we said above, going right back to regular activity on a busted knee is a bad idea. Walking without crutches or a brace right after surgery is a great way to accidentally put too much weight on the knee. Walking may help you improve your range of motion and gently exercise the knee joint. On top of that, trying to avoid stepping on the injured leg can make you overcompensate with the rest of your body and cause more aches and pains in the long run.
Chain Re-Action
Experts sometimes disagree on the safety of open-chain exercise (in which your foot swings or your knee is fully extended with your foot off the ground) as opposed to closed-chain exercises like squats (where your foot is on the floor). However, there’s some research that suggests open-chain exercises can help. Talk to your physical therapist, who may tell you to start with your foot on the ground in early recovery, then work up to just swingin’ that leg around. It’s all about stability and support as you heal.
Get Back to Running with No (or Minimal) Problems
Depending on where you are in the recovery process, your physical therapist might recommend ACL rehab exercises such as:
- Hamstring and calf stretches
- Passive knee extension exercises
- Half squats
- Partial lunges
- Heel raises
- Elliptical training
- Resistance training to build your strength
Find more ACL rehab exercises on the Game Ready blog.
Next Steps After ACL Rehab Exercises
Research shows strengthening your knee after you injure it may prevent you from hurting it in the same way again. Strengthening your quadriceps and hamstrings (front and back thigh muscles) helps with stability. So does having good technique and form when doing any physical activity. Your doctor or PT might also recommend exercises like:
- Core/abs strengthening
- Balance training
- Stretching, agility, and mobility exercises.i
Keep in mind that every injury is different, so work with your healthcare provider, physical therapist, or trainer to find the rehab and prevention program that works best for you.
Resources
- Grayzel J (Deputy Ed.). Anterior cruciate ligament (ACL) injury prevention. UpToDate Medical. https://www.uptodate.com/contents/anterior-cruciate-ligament-acl-injury-prevention. Updated April 2023.
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Ligament. Cleveland Clinic. https://my.clevelandclinic.org/health/body/21604-ligament. Updated July 2021.
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Proffen B, McElfresh M, Fleming B, and Murray M. A comparative anatomical study of the human knee and six animal species. Knee, 2012;19(4):493-499.
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Why weight matters when it comes to joint pain. Harvard Health. https://www.health.harvard.edu/pain/why-weight-matters-when-it-comes-to-joint-pain. December 2019.
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Knee ligament injuries. UW Medicine. https://www.uwmedicine.org/conditions-symptoms/bone-joint-muscle/knee-ligament-injuries. 2024.
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You’ve torn your ACL. Now what? Harvard Health. https://www.health.harvard.edu/newsletter_article/youve-torn-your-acl-now-what. 2019.
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Cavanaugh J, Powers M. ACL rehabilitation progression: Where are we now?. Curr Rev Musculoskelet Med. 2017;10(3):289-296. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5577427/.
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Ma, C. Anterior cruciate ligament (ACL) injury - aftercare. Medlineplus.gov. https://medlineplus.gov/ency/patientinstructions/000681.htm. Published 2019.
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After ACL surgery. UCSF Health. https://www.ucsfhealth.org/education/after-acl-surgery.
- Wilk K, Arrigo C, Bagwell M, and Finck A. Considerations with Open Kinetic Chain Knee Exercise Following ACL Reconstruction. Int J Sports Phys Ther 2021;16(1):282-284.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8341750/
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Anterior cruciate ligament (ACL) rehabilitation. Physiopedia. https://www.physio-pedia.com/Anterior_Cruciate_Ligament_(ACL)_Rehabilitation.
