Quadriceps inhibition or the inability to feel/activate your quadriceps after knee injuries or major knee surgeries like ACL reconstruction can be very frustrating early on in the rehabilitation process. How is it possible that you can’t squeeze your quad?! Luckily for you, we’ll show you our top 7 cues and expert tips to increase your quadriceps activation following surgery!


How To Improve Quadriceps Activation!

The quad set is paramount to re-gaining quadriceps activation. After an injury (which includes surgery), there is lot of swelling in the knee that accumulates. This swelling leads to a phenomenon called arthrogenic muscle inhibition, in which there is an inability to completely contract a muscle despite no injury to the muscle or innervating nerve. This quadriceps activation failure is caused by neural inhibition. It’s essentially the nervous system not allowing the normal pathways of muscle activation to occur. The best evidence to date (Systematic Review from Sonnery-Cottet 2018) supports the use of therapeutic exercise and icing to improve quadriceps activation. Our favorite exercise to re-teach patients quadriceps activation is the all-mighty quad set. The quad set facilitates lots of quadriceps activation practice and helps with the development of a new “brain-body connection”. Follow this foolproof guide provided in this article to wake your quad back up!


knee extension machine prehab guys


How To Wake Up Your Quad After Surgery

Lay on the ground or table and place a rolled-up towel/shirt under your knee. This will act as a lever which will make it easier to activate your quadriceps muscle. Attempt to squeeze your quadriceps muscle using these cues:

  1. Really focus on squeezing your quad
  2. Sometimes touching the muscle, massaging it, or hitting it can help
  3. Think about moving your kneecap up and into your hip socket
  4. Push your knee down into the towel roll
  5. Lift your heel off the table
  6. Move your shin bone in the shape of a “J” by moving your knee down and your heel up at the same time
  7. Squeeze both quadriceps at the same time Happy quad setting!


Improve Your Quadriceps Activation Following Surgery To Improve Your Knee Extension

knee extension mobility program the prehab guys quad set

In order to not only achieve adequate straightening of your knee, but also keep it, you need a strong quad! This program is for anyone looking to truly [P]Rehab their knee before surgery OR work on regaining their knee extension after a surgery or injury. It’s appropriate for anyone regardless of current fitness level and will build you from the ground up to tolerate the end ranges of knee extension. For more about this program click HERE.


The Importance of Knee Extension After Surgery


Other Quadriceps Activation Exercises

Have trouble with the exercise above? Don’t worry, below we will show you some other quadriceps activation exercises that are great for building muscle in this area of the body!


Straight Leg Raise Quadriceps Activation Exercise

Sample Quad Set Knee Extension [P]rehab Program Exercise

  • HOW: Start by lying on your back. Bend your opposite knee. The first step is to let your foot turn out, this will put your hip in the desired position. Next, you must perform a very strong quadricep set by squeezing your thigh as hard as you can. Keeping this constant squeeze, tighten your core muscles, and then lift your leg up into the air. Try to trace an invisible “J” in the air, keeping your toes pointing outwards the entire time. Think of making your leg as long and as straight as you can while lifting it. Then slowly lower back down to starting position and repeat.


  • FEEL: You should feel an entire contraction of the front thigh muscles and your leg working hard, especially the inside part of your thigh.


  • COMPENSATION: You should not be feeling these exercises exclusively in the front of your hip. If you only feel the muscles in the front of your hip working, it means you are not squeezing your thigh hard enough or you are not squeezing the quads when you are lifting your leg. Maintaining the thigh squeeze is the most important part of this exercise!



How to begin strength training the prehab guys quadriceps activation following surgery


Prone Terminal Knee Extension – Hips Down

Sample Quad Set Knee Extension Exercise Program

Get set-up laying on your stomach with your elbows under your shoulders and hips supported on the ground. On the side, you want to perform the exercise, point your toes towards you and start with your knee on the ground. Begin the exercise by squeezing your quads to fully straighten your knee, hold that position, then return to the starting position and repeat. You will feel your quad muscles working with this exercise along with a calf and hamstring stretch behind your knee. Focus on getting your knee fully straight while keeping the rest of your body still.


Prehab Membership The Prehab Guys quad set

The Prehab membership is the anti-barrier solution to keeping your body healthy. Access state-of-the-art physical therapy, fitness programs, and workouts online in the comforts of your own home or gym! Taking control of your health with exercise & education from the palm of your hand has never been easier. Get access to 50+ programs, 100+ unique workouts, and 3000+ exercises to build your own workout routines. Trial it for free, and learn how to get out of pain, avoid injury, and optimize your health with [P]rehab!


Terminal Knee Extension – 3 Way Quadriceps Activation Exercise

Sample Knee Extension Quad Set Exercise Program Video

Get set up standing with a band around and above the knee with the band anchored in front of you. You will perform this exercise in 3 different positions: with your feet side by side, with your working leg in front of your other leg, and with your working leg behind your other leg. To perform the exercise, put tension on the band so that it wants to pull your knee forward, let your knee bend and your foot go onto the toes followed by squeezing your quad, pushing your heel into the ground, and pushing your knee back until it is fully straight. You will feel your quads working with this exercise and maybe even your glutes. You may also feel a stretch behind your knee in the calf and hamstring region when your knee is straight. Don’t let your butt go back and your hip bend when you straighten your knee. The only thing moving should be your knee going backward!


Long Arc Quad – 0 to 90 Degrees

Get set up seated on the edge of a surface with your feet hanging off at a 90˚ angle. Place a band around your ankles. On the side, you want to perform this exercise, kick the leg straight until your knee is fully straight, hold for a moment, then slowly return to starting position and repeat. Your other leg shouldn’t move to keep tension on the band. You will feel your quadriceps, the muscles on top of your thigh working with this exercise. Do not move the other leg, do not move the rest of your body, and limit the motion to your knee.


Closing Thoughts

The quadricep muscle often “shuts down” after a surgery or injury. Waking it up with frequent exercise and consistency is crucial for knee extension. If you are in need of some more formal guidance, be sure to check out our Knee Extension Mobility Program that can optimize your quad activation!


Improve Your Quadriceps Activation To Improve Your Knee Extension

knee extension mobility program the prehab guys quadriceps activation following surgery

Knee extension is not just a recommendation it is needed! Hypothetically, you could walk on a bent knee but this is going to waste energy and ultimately limit your movement endurance. Instead, let’s get you moving efficiently by achieving and keeping full knee extension.


About The Author

Michael Lau, PT, DPT, CSCS

[P]rehab Co-Founder & Chief Product Officer

Michael was born and raised in Northern California but now currently resides in Sunny SoCal ever since attending the University of California, Los Angeles as an undergraduate majoring in physiology. After his undergraduate studies, he received his Doctorate in Physical Therapy from cross-town rival the University of Southern California. As a licensed physical therapist with a strong background in strength and conditioning, Michael likes to blend the realms of strength training and rehabilitation to provide prehab, or preventative rehabilitation, to his patients. A common human behavior is to address problems after they become an issue and far often too late, which is a reactionary approach. He believes the key to improved health care is education and awareness. This proactive approach-prehab-can reduce the risk of injuries and pain in the first place. He is a huge proponent of movement education and pain science. Clinically, he has a special interest in ACLR rehab and return to sport for the lower extremity athlete.



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

About the author : Michael Lau PT, DPT, CSCS


  1. Elyse Lukis October 28, 2018 at 2:36 pm

    Thanks very interesting blog!

  2. Сialis January 3, 2019 at 1:07 am

    Hi there! Would you mind if I share your blog with my myspace group?
    There’s a lot of people that I think would really appreciate your
    content. Please let me know. Many thanks

  3. Jade March 17, 2019 at 3:24 pm

    Any suggestions on someone who had a patella tendon rupture over a couple years ago and still struggles with quad activation and strengthening? I’ve also found myself struggling with finding the right balance of implementating quad exercises and pushing through the tendinitis pain I feel with those exercises

    • Michael Lau March 18, 2019 at 10:08 am

      Blood flow restriction. Will help your with the neuroativation part (if you are still having problems) as well as increasing muscle size. For tendonopathy, you do need to eventually load it. BFR can be a good segway into that.

  4. Erik Boehm March 21, 2019 at 3:40 pm

    I had knee surgery two weeks ago. Medial meniscus repair through orthoscopy. The first two weeks have been anything but routine as week one I found out I had a DVT and a day or two later a PE. After taking blood thinners now for a week, blood pooled in my knee which forced me to have it drained in the ER. That was 4 days ago and swelling has gone down, but I’ve noticed I can not lift my leg, which turned me to this site/video. Due to my circumstances, I wasn’t able to be as active in the first two weeks of recovery and now im finding my quad is not activating properly and doesn’t allow me to walk or pick my leg up. Other then the video suggestions, is there anything else I should look towards doing to help fix this or am I trying to rush things too much? Thanks

    • Michael Lau March 28, 2019 at 8:13 am

      Are you working with a PT? If so, listen to their advice over anything I will say here.

      You need to literally perform hundreds and hundreds of quad sets and straight leg raises a day. You can try NMES with your PT if you are not already. Most importantly, keep the swelling down. Ice ice ice that knee and keep it elevated.

      If you have access to BFR, that may help as well.

  5. Bola fowodu September 10, 2019 at 6:50 pm

    for quads activation, how about ”sit to stand” and stair climbing exercises?

  6. Joan Reilly February 8, 2021 at 12:57 pm

    I’m 3 month post MPFL reconstruction w/ allograft. My quads still not activating immediately. Am doing quad sets, Kneehab, sit to stand, bike, leg presses, etc, going to PT twice/ week, yet has buckled, back to immobilizer several times, still crutchwalking, allowed full weight-bearing, but unable to do so other than when standing still. I got steroid injections, removed 15 cc fluid. Anything else you can think of? Thank you.

    • Sherif Elnaggar February 8, 2021 at 1:05 pm

      Hello! thank you for your question. Unfortunately we are not allowed to answer questions related to direct medical advice as we are not allowed to legally. However, I would continue to stay consistent with your rehab, and discuss different ways to activate your quadriceps with your physical therapist! Do not get discouraged! Every person will respond to surgery of the knee differently, which is completely normal! Continue to stay on track and consistent. Wishing you the best of luck!!!

  7. Zhila Hoo March 22, 2021 at 4:57 pm

    I had MPFL surgery two weeks ago and still I can’t activate my quad (I can’t squeeze the muscle and raise my leg) My knee is still swollen. I’m frustrated with my quads. I can just practice on the quad set at this pint. Any recommendation?

    • Sherif Elnaggar March 23, 2021 at 7:53 am

      Hello Zhila, thank you for your question! Sorry to hear that you have had difficulty with your quadriceps activation. Are you seeing a physio currently? Stay with it and stay consistent, don’t be discouraged as sometimes it takes some time for the quad to “wake up” after surgery! The more consistent you are with exercise, the more improvement you will see! Also, if seeing a physio, that individual can continue to implement various techniques in attempts to help further facilitate activation of your quad. Best of luck to you :).

  8. Zhila Hoo March 23, 2021 at 11:13 am

    Thanks. Yes I’m working with a therapist. How long it takes normally to get the quad back? Can I walk before complete quad recovery?

    • Sherif Elnaggar March 23, 2021 at 12:31 pm

      Unfortunately we are not allowed to answer direct medical advice questions on this platform as it is illegal. We would suggest following up with your physical therapist who could best answer these questions for you in-person!!

  9. Jacob Barber January 7, 2022 at 8:10 pm

    I didn’t have surgery, but did hyperextend my knee and had some bone bruising and small meniscus tear. It’s all healed now but I swear I can’t activate my inner quad (vmo). What should I do to get quad activation again, the exercises listed above? Any other tips?

    • Team [P]rehab January 9, 2022 at 10:28 am

      Hi Jacob!

      We are sorry to hear about your injury, but glad you have healed up! In regards to quadriceps activation, we would recommend starting with our knee rehab program, which covers all the avenues of activating the quadriceps, and then progresses you through step-by-step phases to reach optimal knee health. Please reach out to us at info@theprehabguys.com if you have more specific questions, or need more guidance. Here is the link to the program below.

      URL: https://theprehabguys.com/knee-prehab-program/

      All The Best,

      Team [P]rehab

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