ACL Rehabilitation Protocol

July 15, 2021


Injury > Surgery

This stage looks at assessing the athlete and whether they are a coper or non-coper.

A coper is an individual with good knee stability and the ability to compensate well after
injury. A non-coper will have less stability and increased incidences of their knee ‘giving way’
during daily activities. As such, copers can tolerate sport without the ACL and can avoid
having to undergo surgery.

Everything here is very broad as research is still limited in the area and there are no
definitive guidelines to assessing whether someone is a coper or non-coper. With this in
mind, each individual will be different as well as where their graft is taken from (Hamstring,
Patella, ITB or wherever they decide to do next).

A prehabilitation program will consist of 6-9 weeks over 3 main stages and will depend on
whether progress is constantly being made. The athlete must complete each stage to a
satisfactory level before progressing.

The only main thing found to be avoided is full ROM of open kinetic chain exercises as this
position threatens the integrity of the graft.

Stage I :

  • Return to normal gait and daily activities
  • Reduced symptoms of injury
  • Increased stability in injured leg

Stage II :

  • Increased intensity in uni and bilateral strengthening exercises
  • Introduction to very light plyometrics and jogging

Stage III :

  • Return to normal gait and daily activities
  • Reduced symptoms of injury
  • Increased stability in injured leg

If they have progressed consistently through all the stages, then it is up to them whether they continue without an ACL or whether they opt for surgery.

Stage 1 - Post Injury

Stage 1 is all about giving the graft the best chance to take, reducing infection chance and
gaining normal function back in the leg. It is also a build up into the next stage. If the athlete
is struggling through or has not done this stage, then they have not earnt the right to and
cannot progress to stage 2.

If going for the non-surgical option, the protocol remains the same.

Weeks 1 – 2 After Surgery

Straight after surgery. Not too much should be going on at this point. The biggest key factors for this stage:

  • Rest, Ice, Elevate and Reduce Swelling
  • Maintain clean bandages and clean wound site
  • Start to slowly improve ROM through straightening exercises. Knee extension is very important with less concern for knee flexion at this stage
  • Stationary cycling can start to be implemented towards the end of the second week Slow controlled speed •
  • Nothing is more important than getting the knee straight and not ruining the graft.

Full weight bearing should be built up and commence around the 2-3 weeks post-surgery. Compression bandages can still be worn afterwards for athlete’s comfort.

Weeks 3 – 4 After Surgery

  • Looking to work towards normal gait pattern
  • Work to be able to obtain full extension of the leg, and ~90 degrees flexion
  • Introduction of double leg, low intensity closed chain exercises as well as isometrics
  • Open kinetic chain exercises allowed but not through full ROM, specifically full extension as this strains the graft. Unilateral balance and stability exercises being introduced
  • Slowly increase speed on exercise bike
  • Train opposite limb for crossover effect. High intense and heavy sets are optimal for neuromuscular crossover.

Stationary cycling is a good way to maintain fitness and help strengthen lower limb muscles. It is also good for developing and maintaining ROM. 10-20 Minutes at a low intensity is enough per day. Seated boxing is another fun way to work cardiovascular fitness and add variety to training.

Stage 2 - Preparing for Running

Stage 2 is about getting the athlete prepared to start running again. It is normal for there to still be some pain and discomfort, as well as numbness to still occur. Deep flexion and extension can still cause pain, although it depends on the individual. Being able to fully extend the leg is very important in these early stages.

Intermittent episodes of swelling and discomfort can still occur, especially as gait and weight bearing start to return to normal. If so, just adjust exercises accordingly to not cause further discomfort.

Months 1 – 2 After Surgery

  • Progress single leg stability exercises – going to full extension
  • Keep working ROM – Start to implement full ROM extension exercises
  • Work muscles surrounding ACL – e.g. calves, glutes, quads, adductors through low intensity and isometric exercises
  • Squats and wall sits can start to increase ROM if minimal discomfort is present
  • If pain free, implement single leg closed chain exercises – e.g. step ups, squat to bench

The graft is at its weakest point at roughly the 10-week mark, and then gradually increases in strength over the next year. Although the athlete may be feeling good, make sure to stress the importance of holding off on running or jumping for the next few weeks.

Months 2 – 3 After Surgery

  • Start to even out imbalance between legs
  • Implement or progress single leg exercises depending on how athlete is feeling
  • Double leg compound lifts may start to be introduced at low intensity
  • Gait should be back to or close to it was prior to surgery

If access to an anti-gravity treadmill is available, running can commence earlier with clearance from your Physio. Otherwise hold off running until approximately the three-four- month mark, also to be cleared by the Physio.

Stage 3 – Implementing and Increasing Running and Preparing for COD

The start of this stage should see the athlete start to jog and then run in a straight line. Some pain and aching around the joint is normal. Very light plyometrics can start to be introduced and slowly progressed with a focus on landing mechanics.

The aim of this stage is to re-introduce running for the athlete and then get them prepared to change direction. The biggest emphasis on this stage is to increase confidence running and make sure gait is normal. It is normal and very common to be nervous.

Months 3 – 6 After Surgery

  • Introduce straight line running
  • Curvilinear running can slowly be introduced towards the end of this stage
  • For athletes anxious about running, walk throughs of technique can slowly be implemented and also encouraged
  • Running can be slowly progressed to slight bends and then curvilinear running
  • Split stance movements and plyometrics can start to be introduced and progressed with emphasis on landing mechanics
  • Maintain strengthening exercises and reducing variances in legs

It is important to not push the graft too hard too early, especially when reintroducing running as this can place strain on the graft. This is a long stage and there is plenty of time to improve slowly and make sure you are doing this properly. Focusing on small attainable goals is a great way to boost motivation and psychological well- being in athletes that may be struggling.

It is common for a big psychological boost following clearance to run, but monotony can set in shortly after. Again, this is completely normal.

Stationary cycling and swimming can be continued and increased in intensity for the athlete to maintain aerobic conditioning. Other activities that are low impact on the knees such as boxing can be enjoyable ways to stay fit and work on a new skill.

Stage 4 – Increased Change Of Direction and Preparing for Return To Training

The individual should be running and have started curvilinear running, if even at a slow pace. As volume and intensity of running increases, it is important to constantly assess competency.

Change of direction will continue to progress to sharper cuts throughout the stage to get the athlete prepared to return to sports specific training. Introduce lateral movements for both strength and light plyometrics.

Months 6 – 9 After Surgery

  • Keep progressing COD drills and increase confidence in the athlete
  • Maintain strength work with increased multi-planar movements
  • Start to introduce slight perturbation
  • Increase intensity of plyometrics and start to introduce lateral movements
  • Athlete should have commenced or start to commence light skills work related to their sport

General consensus of research is that the athlete should ideally be ~20 % difference in quad and hamstring strength between injured and non-injured leg at the 6-month mark. Although missing this is not a big deal as there is still plenty of time.

Stage 5 – Work Weaknesses and Prepare for return to play

Running, changing direction and returning to sport specific skills, even if only light, should have been achieved. This stage is about getting the athlete prepared to return to playing and training.

The 12-month mark should be the earliest they return, even better if they can hold off for another month or two, with 13-14 being the ideal. Each month will further reduce chances of re-injury.

Focus on any weaknesses the athlete may show or imbalances between limbs.

Months 9 – RTP

  • Increase competency with COD drills and add reactionary components
  • Continue to increase confidence and reduce anxiety of returning to sport. Being exposed to training is key.
  • Help to ensure the athlete is psychologically ready to return to play
  • Even out any imbalances that may still persist
  • Focus any weaknesses that may detract from returning to play i.e. hamstrings, quads etc.
  • Start re-introducing sprints – starting with low volume and short distances

One of the biggest contraindications for returning to sport is psychological readiness. If they have reached this stage in their rehab then physically they are able to return, they just need to be mentally prepared. Slowly returning to warmups and advancing through drills is a great way to start re- introducing yourself to your sport. This also helps with the gradual return to playing and helps with psychological readiness.

Quad and Hamstring strength should be less than ~10% between injured and non-injured leg by 12-month mark, and definitely before returning to play.

Post Stage – Return to Play – Maintain and Build

The athlete should have eased into their return to sport, slowly building up their match endurance and confidence. At this stage the athlete can stop being treated as a rehab client for the sake of S&C and programming and undergo the usual training for where they are in season and what they need as an individual.


  • Help their return to play however the individual needs
  • Keep increasing confidence
  • Work on any weaknesses that may still persist

The biggest contraindication to an athlete returning to play is their psychological readiness. Physiologically they will be as prepared as they can, but mentally they may be struggling with the realisation that they will be put back in the position in which they got injured.

After the 12–14-month mark and as the athlete is returning to play they will go onto a more standardised strength and conditioning program, while maintain they are still an ‘ACL rehab client’. Timeframes here will be very individual based.

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