whats missing in ACL rehab the prehab guys

What’s Missing in ACL Rehab?

There is a problem with ACL Rehab. If you tore your ACL, were you told that surgery was your only option? Were you told that after having surgery to address a torn ACL your risk of re-tear is twice as high as the population at large? Were you told that returning to sport within a year after surgery significantly increases your risk of re-tear? Did a physical therapist ever explain to you the importance of regaining quad strength and using that to dictate your return to activities like running, jumping, and playing sports, rather than just time alone? Did anyone tell you that your chances of developing osteoarthritis increase substantially after an ACL tear, whether you have surgery or not? If your answer to any of the above questions was no, then the current system is doing you a disservice. This article will take a look at what is missing in our current model for ACL rehab and how technology can help you safely return to sport and protect the long term health of your knee.


Is something Missing in ACL Rehab?

Yes. In fact, many things are missing. First, some numbers:


  • After ACL surgery, females are 5x more likely to either re-tear or tear their other ACL.



  • This leads to a higher prevalence of developing osteoarthritis and increases the need for an early knee replacement.


Simply put, we NEED to do better!


ACL Anatomy

Whats Missing with ACL Rehab? The prehab guys

Image courtesy of FixKnee


Before I go any further, I want to make one note. Throughout this article,ย  you will hear me reference the importance of knowing your quad strength.ย A couple ways to measure your quad strength indirectly that you can do on your own is a single-leg squat test or indirect strength testing!


So What is Missing in ACL Rehab?

Recent advances in ACL research have brought to light the need for a 12 month guided rehab progression and unfortunately our current model of insurance based visits simply hasn’t caught up. Some patients are wisely advised that they should not return to playing sports within a year of their surgery. Unfortunately, our insurance-based model has failed to keep up with this burgeoning research and most patients are forced to stop physical therapy after about 4 months. This leaves many patients guessing as to when and how much they should run, how to incorporate plyometrics, and how to safely progress back to sport.

As most patients have this surgery to allow them to return to these high level activities, they miss guidance through ACL rehab during the portion that is most important to them! When it comes to returning to sport and fitness and protecting the long term health of their knee, nobody should have to guess!


Are Knee Extensions Safe And Functional For ACL Rehab?

Watch this youtube video as Mike breaks down the truth behind knee extension exercises not only for ACL rehab, but for other knee related injuries!ย 


Why do we need to wait so long?

While a year may seem like a long time, we need to remember what an ACL Reconstruction is. A surgeon is taking a portion of a tendon, usually from your hamstring or patella and replacing your Anterior Cruciate Ligament (ACL) with it. Want to learn more about ACL grafts? Read this article!


  • Ligaments connect bone to bone


Tendons and ligaments have different properties. Fortunately, we aren’t relying on the tendon graft itself to immediately hold up as a functioning ACL. A successful ACL reconstruction relies on your body’s ability to incorporate the tendon graft into your knee and change the properties of that tendon into those of a ligament. Nobody spent a lot of time trying to come up with a cool name for this and it is simply called theย  ligamentization of the graft. It requires two things:

  • Time


  • Gradual exposure to load



what is the acl prehab guys whats missing in acl rehab


In fact, this process is so critical that researchers found that for every additional month a patient waited to return to sport after surgery, all the way up to 9 months, the reinjury rate was reduced by 51%!

  • This means that if you are itching to play soccer 8 months after your surgery, you can decrease your chance of re-tearing your ACL simply by waiting another month!


While the numbers might not be quite as staggering, many of these researchers still recommend waiting until a full year after surgery to return to playing sports for young athletes and weekend warriors.


What can I do to get ready?

The most important thing you can do during your rehabilitation is build as much quadriceps strength as you possibly can.

Unfortunately, this basic principle is often sped through for more exciting, “functional” exercises. Tearing your ACL leads to a cascade of biological events that decrease both your quadriceps strength and your nervous system’s ability to use your quadriceps! A similar cascade takes place after a surgical intervention. This means that you need to spend months isolating and directly building your quadriceps after surgery. Read this article to learn how you can stay strong after surgery! Remember that other muscles (and your other leg) can compensate for your quadriceps during functional exercises. For exampleย  if you are squatting without altering the exercise to focus on your surgical quadriceps or first establishing a foundation of quad strength: you are literally training yourself not to use your quad!


If this sounds simple, recognize that:

  • 2 years after surgery only ~60%ย  of patients had quadriceps strength within 90% of their nonsurgical leg.


  • Every 1% increase in quadriceps strength (compared to the nonsurgical leg) leads to a 3% reduction in re-injury rate.


Listen: Is It Safe To Use the Knee Extension Machine to Train your Quads?

knee extension machine safe to use prehab audio experience what is missing in acl rehab

Quadriceps strength is:

  • Not easy to get back


  • Not everyone does get it back


  • ย Is a major contributor to the high rates of re-injury after ACL surgery.


Gradual Progression

Another factor that is critical for success is following a step-wise progression that gradually exposes your knee to increasing loads. Our bodies are smart and adapt to the load they are placed under.ย  The process of ligamentization actually would not occur in full if there was no stress placed on the graft.

The “Goldilocks Principle” applies here! You want enough load that you are stressing the knee to induce a response, but not so much load that you are overstressing your joint and ligament and delaying healing.

The entire ACL rehab process is unique to each person and beyond the scope of this article but generally it should include:

  • Establishing symmetrical strength and range of motion


  • Progression to increased weight-bearing activities


  • A Walk/run progression


  • Incorporation of plyometrics


  • Gradual introduction of sport specific activities


  • Inclusion of reactive activities


Throughout this process, your swelling and soreness should be monitored as this is the best way to tell if you are ready for the stage of rehab you are doing! An increase in swelling and and soreness means you are doing more than your knee is ready for and need to take a step back!


Lacking Knee Extension Following ACL Injury? We Are Here To Help!

knee extension overhaul prehab program the prehab guys

Knee extension is one of, if not, the most important aspect of rehab to focus on immediately following an ACL injury and/or surgery. The Knee Extension Overhaul [P]Rehab Program is the ultimate resource for those looking to regain full knee extension โ€“ whether thatโ€™s before surgery or after. The importance of full knee extension for functional demands and life in general is crucial! Ask any orthopedic surgeon or rehabilitation specialist, NOW is the time to regain your full knee extension. Learn more HERE!


How will I know I am ready?

“The future is already here, it’s just not very evenly distributed” – William Gibson.

Despite all of the statistics I’ve thrown out above, if you are struggling with ACL rehab, there is hope! Proper and full rehabilitation, culminating in a battery of tests to determine readiness for return to sport has shown to reduce re-injury rates by 84%! You can return to sport after ACL surgery and you can do so with full confidence in your operative leg but it takes a few things:

  • Time


  • Patience


  • Consistency


  • Hard work


Return To Sport Testing

Prior to return to sport, you want to have symmetry of >90% when comparing your surgical leg to your nonsurgical leg for the follow tests:

  • Quad strength – this is most easily done by comparing 1 rep max on a knee extension machine


  • Single Leg Hop for Distance


  • Crossover Hop for Distance


  • Triple Hop for Distance


  • 6 meter timed hop test


When in doubt, strengthen your quads!


Are Knees Over Toes Exercises Safe For ACL Rehab?


Closing thoughts on What’s Missing in ACL Rehab

  • The current model of ACL rehab is insufficient to address the needs of this population.
    • Patients are given just 4-6 months of physical therapy for a 12 month rehab program.



  • There are options to improve these statistics:
    • Proper rehabilitation and testing is shown to reduce re-injury rates by 84%!
    • The rise of the internet and technology offers patients the ability to access digital programming and ACL rehab specialists from anywhere in the world for as long as they need to complete their rehab journey.



  1. Paterno MV, Rauh MJ, Schmitt LC, Ford KR, Hewett TE. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport.ย Am J Sports Med. 2014;42(7):1567-1573. doi:10.1177/0363546514530088
  2. Grindem, Hege PT, PhD1; Eitzen, Ingrid PT, PhD2; Engebretsen, Lars MD, PhD3; Snyder-Mackler, Lynn PT, ScD, SCS, ATC, FAPTA4; Risberg, May Arna PT, PhD1 Nonsurgical or Surgical Treatment of ACL Injuries: Knee Function, Sports Participation, and Knee Reinjury, The Journal of Bone and Joint Surgery: August 6, 2014 – Volume 96 – Issue 15 – p 1233-1241 doi: 10.2106/JBJS.M.01054
  3. ร˜iestad BE, Engebretsen L, Storheim K, Risberg MA. Winner of the 2008 Systematic Review Competition: Knee Osteoarthritis after Anterior Cruciate Ligament Injury.ย The American Journal of Sports Medicine. 2009;37(7):1434-1443. doi:10.1177/0363546509338827
  4. Claes S, Verdonk P, Forsyth R, Bellemans J. The “ligamentization” process in anterior cruciate ligament reconstruction: what happens to the human graft? A systematic review of the literature.ย Am J Sports Med. 2011;39(11):2476-2483. doi:10.1177/0363546511402662
  5. Grindem H, Snyder-Mackler L, Moksnes H, Engebretsen L, Risberg MA. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study.ย Br J Sports Med. 2016;50(13):804-808. doi:10.1136/bjsports-2016-096031


About The Author

Tommy Mandala, PT, DPT, SCS, CSCS

[P]Rehab Writer & Content Creator

tommy mandala the prehab guysTommy Mandala is currently a Doctor of Physical Therapy and Board Certified Clinical Specialist in Sports from New York City, where he specializes in ACL Rehab. Prior to that he trained as a sports resident at the University of Delaware working with the ACL researchers in the field. He has additional experience working with the Philadelphia 76โ€™ers NBA G-league affiliate, the Delaware Blue Coats. His experiences have given him a passion and expertise for treating patients struggling with ACL Rehab. One of his favorite aspects of his job is empowering patients to return to sports with full confidence in their knee after ACL Reconstruction.

Instagram: @All_In_ACL


Disclaimer – The content here is designed for information & education purposes only and is not intended for medical advice.

  • BlackTie CBD Flower
    Posted at 01:45h, 27 April Reply

    Thanks for your article! I faced a similar situation. I also had some minor problems, and for a while I was looking for a way out to solve them. I turned to specialists. I think this is the best solution. When there is a problem, I try not to jump to conclusions, but to listen to the opinions of other people. I was able to cope with the pain when I took my health seriously. I just made the decision not to torture myself anymore, and started going to workouts regularly with a personal trainer. Individual approach and perseverance decided everything!

  • Tommy Mandala
    Posted at 10:55h, 27 April Reply

    Thanks so much for your comment! What you said perfectly encapsulates this problem! Turning to a specialist to give you the guidance and hold you accountable to taking your health seriously are CRUCIAL. Sorry you went through that, but happy to hear you are doing well!

  • Fidel B.
    Posted at 21:18h, 01 June Reply

    Any hamstring (semi-T, gracilis) advice? Doc took both of those tendons and my hammy has been weak ever since the surgery which was in 2013.

  • cbd reakiro
    Posted at 06:02h, 20 July Reply

    interesting to read more about acl, my wife have problems with it and I thing I will give her to read this, thank you!

    • Prehab
      Posted at 07:24h, 21 July Reply

      You are most welcome!! Thank you for your positive comment!

  • Aditya Mitra
    Posted at 20:55h, 11 August Reply

    My ACL healed post injury but I have a 10ยฐ straighter leg now.

    I see a lot of stuff on how to increase extension. But is it possible to decrease extension to match the uninjured side?

  • Laura wilson
    Posted at 13:40h, 12 October Reply

    Great info! I am 3 weeks post op. Do you have experience with ACL /MCL combo allograft and how much this changes the progression I should expect.

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