4 Big ACL Prehab Exercises and Goals Before Your Surgery!


Once the decision is made to have ACL surgery it is very important to prepare your knee for surgery! Commonly referred to as ACL Prehab!

The benefits of ACL prehab are significant. Research studies have shown that athletes who completed their ACL Prehab were on average able to advance their post surgery recovery faster than those people who did not perform knee rehabilitation before surgery.

The decision to have ACL surgery is optional of course and we would recommend that you seek multiple opinions on your unique circumstances prior to proceeding with an operation.  However, if the decision is made to proceed with a knee reconstruction than it is very important that you prepare your knee for surgery.

ACL Prehab effectively refers to knee rehabilitation exercises and protocols before surgery.  ACL prehab helps to minimise the effects of an ACL tear on muscle condition, stiffness and swelling surrounding the knee.  Which in turn can plays a significant role towards a more advanced recovery time following your reconstruction.

Improving the physical condition of your knee leading into ACL surgery enables you to start your post-surgery rehabilitation from a higher level of strength and fitness

Below we discuss our view on the 4 most important ACL prehab goals to prepare you knee for ACL surgery including exercises to help you achieve these goals.

The intensity of your ACL prehab exercises should essentially be guided by the level of pain and swelling in your knee.

You should also have an in-depth discussion with your surgeon and physio to agree upon an ACL prehab program that prepares your knee for ACL surgery.

ACL Prehab Goal 1 – Knee extension

  • Restoring full knee extension is the key to preparing your knee for ACL surgery
  • There are a number of exercises that can assist with knee extension including locking your knee out straight for 20 to 30 minutes at a time
  • This can be done by sitting on a flat surface or floor with a towel underneath your foot
  • Locking and straightening your knee it is also one of the most critical components of your ACL recovery after surgery
  • Therefore by completing knee extension exercises before surgery you will also learn one of the most critical exercises that needs to be completed 3-4 times a day immediately after surgery

ACL Prehab Goal 2 – Knee flexion 


  • Another important element of your knees performance is to restore knee flexion
  • Use an exercise bike, ride for 10 to 15 minutes a day starting with a high seat position. As your knee condition improves and swelling reduces, gradually lower the seat position to further improve your knee flexion.
  • Also try heel slides by sitting on a chair on a flat slippery surface such as floor boards and move your bad leg backwards along the floor behind you and forwards again to the starting position.  Complete this exercise with 20 to 30 repetitions and do this 3 times a day.

ACL Prehab Goal 3 – Reduce Knee Swelling

  • Regular icing & wear a compression bandage – one of the key elements of reducing knee swelling and controlling pain is to ice regularly for 15 to 20 minutes at a time
  • Ice as much as you can for improved benefits. Also wear a compression sleeve on your knee to help constrict blood flow

ACL Prehab Goal 4 – Quadriceps strength 

  • Notwithstanding the above exercises which will assist with returning leg size and strength, it is important to improve your quadriceps strength by performing additional gym exercises such as squats and lunges
  • Start by completing 3 sets of 10 of standing squats.
  • The squats can be performed on one leg to isolate the injured knee and for a more challenging workout weights can be introduced

In addition to the above 4 goals, there are of course other physical exercises that you can add to you ACL prehab.

We recommend that you consult your surgeon and physio for additional exercises that are specific to your individual circumstances.

What is ACL Prehab

  • ACL Prehab is a term used to describe the process of preparing your knee for ACL surgery.   ACL Prehab is effectively another way of referring to knee rehabilitation exercises and protocols before an ACL operation
  • The importance of completing ACL Prehab is at times not reinforced to patients by their surgeons, however this can depend on the experience of the Orthopaedic surgeon who should at minimum be
  • Research has shown clear benefits in returning strength and size back into the leg plus restoring range of motion prior to ACL surgery
  • The trigger point to start prehab is often when the decision is made to have ACL surgery.  However rehabilitation after an ACL tear should start immediately following the injury.  One of your first goals is to reduce and control swelling by managing your injured knee through rest, ice compression and elevation.  This includes implementing RICER and No HARM principles.
  • In the first 48 to 72 hours after an ACL tear there is often significant bleeding into the knee joint due to torn blood vessels.  Therefore action to reduce knee swelling immediately after tearing your ACL is particularly important
  • Following on from this initial period 48 to 72 hour period, ongoing management of knee swelling should continue and from time to time your may notice an increase in knee swelling such as after completing your prehab exercise sessions
  • Walking after an ACL tear is normally achievable for most people, however depending on the level of knee swelling and stiffness that has resulted from your injury you may initially require the use of crutches until stability is returned
  • Your surgeon and physio should also recommend exercises that focus on restoring range of motion and knee strength.  Use common sense and gradually build up the intensity of your exercises
  • As noted above, the intensity of your ACL prehab exercises should essentially be guided by the level of pain and swelling in your knee

ACL Prehab risks that you should avoid

  • Sudden changes in direction or pivoting should be avoided as this can cause the knee to buckle and cause damage to the knee cartilage as a result
  • Without the ACL intact to support such movements there is an increased risk of causing further damage to the structure of the knee
  • Therefore a common sense approach should be followed with your prehab and how go about your daily activities prior to ACL surgery

Does an ACL tear impact your knee function?

  • The onset of pain and swelling after an ACL tear often results in a reduction in knee functionality and can overall lead to a loss of conditioning in your knee.
  • However the degree of impact that an ACL tear or injury has on your knee can vary from person to person
  • Typically within the first 24 to 48 hours there will be noticeable bleeding and some pain as a result of the tear which can lead to a feeling of knee stiffness and loss of function.  The loss of knee stability can impact your walking which may require you to use crutches temporarily
  • A decrease in range of motion in your knee is often evident with a decline in your ability to fully extend and flex your knee.  It is important to address issues with range of motion with ACL prehab prior to undergoing surgery.

Is ACL rehab before surgery similar to post-surgery rehab?


  • The exercises and recovery protocols required to prepare your knee for surgery are closely related in nature to the types of ACL recovery exercises that you will be need to do in the early stages of your post surgery recover
  • If you have torn your ACL for the first time one exercise or goal that you are likely to hear a lot about is knee extensions.
  • The key to both a successful ACL prehab and the early stages of your ACL recovery following surgery is to restore full knee extension

What is the purpose of ACL Prehab before surgery?

  • The primary purpose of ACL prehab is to restore full knee extension, improve knee flexion, improve range of motion, regain quadriceps control and to reduce swelling
  • After an ACL tear it is likely that you will experience a number of adverse symptoms relating to your knee function such as excess swelling, restrictions with range of motion and loss of strength
  • Research studies have found that a decline in range of motion or strength before surgery can increase the risk of a loss in knee function going forward
  • ACL prehab also introduces you to the types of exercises that you will performing in the early stages of your post-surgery rehabilitation
  • The more that you practise your ACL prehab exercises, the better you will be able to perform those same or similar exercises after surgery and as a result improve the quality of your rehabilitation sessions
  • Psychologically speaking, ACL prehab can help prepare your mindset for the exercises that you will be required to do after surgery

Will you recover faster from ACL surgery if you do prehab before surgery

  • Studies have found that people who complete their ACL prehab are likely to be further advanced with their knee strength and functional performance post surgery compared to people who did not participate in an ACL prehab program
  • An effective ACL prehab program sets the foundations for your recovery after surgery but yet it is still important to be realistic about when you can return to sport and activity
  • Your ACL recovery timeline after surgery is not a 4 to 6 week injury. It is at least a 4 to 6 month recovery before you can consider returning to sport and at least 9 to 10 months before you can recommence full competition.

When do you need to begin your ACL Prehab

  • ACL prehab can effectively commence immediately after the injury.  In the first 48 to 72 hours after the injury your first priority will be to control swelling by icing frequently and wearing a compression sleeve
  • Once swelling and pain is under control you can gradually introduce exercises as recommended by your physio
  • Walking with a torn ACL is encouraged as long as you feel comfortable, however it is best to avoid any sudden twisting or pivoting movements with your prehab
  • Regardless of whether or not you have decided to have an ACL reconstruction, starting your ACL prehab shortly after an injury will help preserve the condition of your knee, minimise the effects of knee stiffness and assist in determining the level of instability in your knee

Is ACL Prehab always needed to prepare for surgery

  • Generally speaking from a medical point of review there is no rush for you to have a ACL surgery unless your knee is giving way.  Each individual decision should be made on a case by case basis.
  • Limiting the number of giving way episodes is important as it can reduce the chances of causing additional damage to other important structures in the knee
  • If the decision is made to have surgery than it is critical that you complete ACL prehab and minimise the loss of conditioning surrounding the knee
  • If you are unsure about whether or not to have surgery than it is best to speak to a number of medical practitioners and seek a variety of perspectives and opinions

Important questions that you should ask prior to ACL surgery

  • Whilst there are a number of actions you can take to prepare yourself for ACL surgery there are also a number of decisions to be made
  • Whilst some people are comfortable to solely rely upon the advice of their therapist, it is also important that you do your own research and seek multiple professional opinions
  • You should be clear about the choices that you have at your disposal such as the pros and cons of ACL surgery

Example questions:

Question 1: Do I require an ACL reconstruction or not?
  • It may sound obvious but it is really important that if you incur an ACL tear that you do the proper due diligence to assess whether or not ACL surgery is the right option for you
  • For some patients knee instability is evident immediately  and the decision to have ACL surgery is clear. In other cases it may be possible to meet your activity goals without surgery
  • Everyones situation is different. It is recommended that you seek multiple medical opinions prior to making a decision on how to proceed forward
  • The more information and research you can gather in regards to your specific circumstances the more likely you are to achieve a successful outcome
Question 2: How do I choose a surgeon to perform the operation?
  • The reality is that an ACL operation can be an expensive procedure and regardless of the profession or industry you should be cautious when taking advice from a person who stands to financially benefit from the advice they offer
  • It is really important to choose a surgeon who has significant and relevant experience in performing ACL reconstructions
  • Typically you would look for a surgeon who performs at least 2 knee reconstructions a month and whose patients have historically had a low re-tear rate
  • A surgeon who is inexperienced may not deliver the same outcome as a surgeon who has performed many successful ACL reconstructions
  • Therefore when you meet with a surgeon, ask how many ACL reconstructions they perform each month and for how long
  • An experienced orthopaedic surgeon should not have any reservation discussing their own prior experience
  • Whilst your local GP or physios may offer you their own referral to see a surgeon – it is also important that you do your own research to determine which orthopaedic surgeons in your region are well regarded with ACL surgery specifically. Seeking a second opinion is recommended
Question 3. What ACL graft type should I have?
  • Research has found that the re-tear rates and risk of injury associated with each graft type is different
  • Ensure that you understand and have a conversation with your surgeon about which graft type will be used in your operation and ask why that is their preference
  • There are a number of ACL graft options available to a patient which includes a patella or hamstring tendon graft, allograft, and LARs. There is no shortage of written opinions in the media on graft types and new innovations
  • Up until today, experienced ACL surgeons continue to preference the tradition graft choices (Such as patella tendon and hamstring grafts) which have historically recorded the highest success rates amongst sport athletes

Importantly, completing an ACL recovery program including ACL prehab before surgery is critical to the success of your rehabilitation following a knee reconstruction.

What do I need to do on the day of ACL surgery?

Your surgeon will provide you with a running sheet of what to expect on the day of surgery.


If the decision is made to have ACL surgery, then it is really important that you prepare your knee for the operation with strength and conditioning exercises.

This includes restoring knee extension, range of motion, improving quadriceps strength and reducing swelling.

ACL Prehab Goal and Exercise Number 1:

Full knee extensions

The key to preparing your knee for ACL surgery is to restore full knee extension by regularly practising locking your knee out straight before your operation!

ACL Prehab Goal and Exercise Number 2:

Knee Flexion and Range of Motion

Knee flexion exercises should also be included in your ACL prehab.  Riding a bike is amazing for ACL injuries and will help build strength and restore knee flexion!  Heel slides whilst sitting on a chair are also effective.

ACL Prehab Goal and Exercise Number 3:

Reduce knee swelling

Icing as much as you can after an ACL injury and wearing a compression bandage will help you reduce knee swelling before surgery.

ACL Prehab Goal and Exercise Number 4:

Quadriceps strength

Returning leg size and strength by exercising your quadriceps is important prior to surgery.  Squat and lunges are highly effectively exercises for preparing your knee for ACL surgery. Your physio can also help recommend a gym program.

Use common sense when performing your ACL prehab exercises. Avoid activities that require sudden twisting or cutting motions!

Good Luck With Your ACL Prehab!

Click the link below for a copy of your Free ACL Recovery Checklist:



  1. Susan Wright

    Thank you for your clear and helpful guidance for people experiencing a torn ACL! I’m quite active–exercise almost every day (walking, biking) and play tennis twice a week (not super strenuous but still a good workout). I have completely torn the ACL for my R knee. It was initially acutely painful for about a week. I used icing and 200 mg of ibuprofen a few times and the pain eased. I no longer feel any pain and walking is no problem. An MRI has shown a complete tear of the ACL, a meniscus torn in 2 spots, and cartilage damage! In your article, “Can you walk with a completely torn ACL?”, p.5 (top), you say that it’s good to “undertake gym and strength work on your knee to build functionality back to pre-injury levels…” Could you possibly send details? The same exercises as for prehab ? Any additional ones? Many thanks!
    Susan Wright

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