31 Best ACL Strengthening Exercises After ACL Surgery

An ACL injury or anterior cruciate ligament injury is more common than you may think.  I know this personally as I have torn my ACL 4 times.

The largest issue with most ACL surgery protocols is that the majority of them provide the same 5 generic exercises. Although many ACL protocols include ACL strengthening exercises, they are not specific to you as the patient.

Approximately 1 in 3500 people in the United States will tear their ACL this year. This percentage is even higher in high risk sports such as basketball, soccer, football and skiing.

ACL injuries are tough injuries with very long recoveries so you want to make sure that you are making the most of your recovery time by performing exercises that are right for you specifically. This post will provide the 31 best ACL strengthening exercises after surgery from a physical therapist who has underwent ACL surgery 4 separate times.

What is an ACL?

An ACL connects your femur (upper leg, thigh bone) and tibia (lower leg, shin bone.) It provides stability in the knee joint. The primary role of the ACL is to provide stability by preventing the tibia from coming too far forward in front of the femur.

The ACL crosses the middle of the knee joint diagonally while the posterior cruciate ligament connects the tibia and the femur diagonally the other direction.

The most common mechanism of injury for ACL tears is during pivoting motions, specifically when the knee is in and the toes are out. This creates excessive internal rotation of the knee.

The 2 most common treatment options for an ACL tear are surgical or nonsurgical with physical therapy.

Grades of ACL Sprain

The severity of the ACL sprain will impact the way the acl injury is treated. For example, typically a grade I ACL sprain can be treated conservatively with rest and physical therapy.

Typically a grade III ACL sprain will result in surgery due to the instability caused by a complete rupture of the ACL. A grade III sprain also increases the risk of injuring other knee structures such as the MCL (medial collateral ligament) and the meniscus.

How to treat a grade II ACL sprain will vary depending on the symptoms. In some cases if symptoms are mild, this grade of ACL sprain can be treated non surgically in physical therapy, however if symptoms are moderate to severe and the knee has instability, you may need surgery. The type of activity you plan to return to will also depend on how to treat a grade II ACL.

• Grade I ACL Sprain
  • The ACL is stretched and mildly damaged, however is is still able to fulfill its job of providing knee stability to the knee joint.
• Grade II ACL Sprain
  • The ACL is stretched to a greater extent than in the grade I sprain and it is now considered loose. This is often called a partial ACL tear.
• Grade III ACL Sprain
  • This is considered a full tear or acl rupture and typically results in an unstable knee.
  • Most likely to need surgical intervention.

Torn ACL Exercises To Avoid

The torn acl exercises that you should avoid after tearing an acl are any exercises that place excessive stress on the knee such as deep squats, especially pistol squats, pivoting exercises and jumping. Eventually towards the end of your recovery process you will be able to return to these activities, but not in the first phase of recovery.

ACL Strengthening Exercises

This section will be divided into sections depending on where you are in your recovery process and what you need to work on. It is important to note that the following exercises in this rehabilitation program are designed for only an ACL reconstruction surgery.

If you also had a meniscus tear you may have range of motion and weight bearing restrictions. These are typically nonweight bearing for 6 weeks and no knee flexion past 90 degrees for the first week. In this case pelase follow the protocol outlined for you by your surgeon.

These 31 ACL strengthening exercises include 1. Ankle Pumps 2. Heel Slides 3. Quad Sets 4. Straight Leg Raises 5. Bridge 6. Weight Shifting 7. Standing Marching 8. Clamshell 9. Pillow Squeeze 10. Hamstring Stretch 11. Calf Stretch 12. Hamstring Curls 13. Step Ups 14. Min Squat 15. Wall Squat 16. Single Leg Bridge 17. Bridge With Hamstring Curl on Physioball 18. Single Leg Balance 19. Leg Press 20. Chair Squat 21. Lateral Lunge 22. Single Leg Romanian Deadlift 23. Slide Board Lunges 24. Monster Walks With Resistance Band 25. Side Steps With Resistance Band 26. Step Up With March 27. Step Down 28. Single Leg Squats 29. Single Leg Wall Slides 30 Front Plank 31. Side Plank.

Post Op: Weeks 1-2

The goal of the first 2 weeks is to decrease swelling, increase circulation and improve quad activation and knee range of motion. These exercises include 1. Ankle Pumps 2. Heel Slides 3. Quad Sets 4. Straight Leg Raises 5. Bridge 6. Weight Shifting 7. Standing Marching 8. Clamshell 9. Pillow Squeeze 10. Hamstring Stretch 11. Calf Stretch.

1. Ankle Pumps

• This exercise is great to help decrease swelling and risk for DVT.
• This exercise is best performed while lying on your back with your legs elevated.
• Begin by bringing your ankles and toes towards you and then push them down like you are pushing down on a gas pedal.

2. Heel Slides

• This exercise is great for improving knee mobility.
  • This increased the range of movement of knee flexion or the ability of the knee to bend.
• Start on your back with a sheet, towel or strap.
• Now bend your knee while using the sheet to help your knee bend. Bend the knee to the point that you feel a stretch/ slight discomfort and then slowly use the sheet to straighten out your knee again.
• Again if you have range of motion precautions, only bend your knee within your precautions.

3. Quad Sets

• This exercise is great for quad activation, muscle strength, specifically leg strength and improving knee range of motion of extension.
  • Knee extension is the ability for your knee to remain in a straight line.
• Start by placing a small rolled up towel underneath your ankle or knee and tighten your quad or thigh muscle by pushing your knee down into the surface below you.
• This exercise can also be performed with electrical stimulation in physical therapy.

4. Straight Leg Raise in 4 directions

Start by performing the straight leg raises in your locked brace.

Straight Leg Raise Flexion

• Lie on your back with your injured knee straight and your opposite, uninjured leg bent.
• This will take the stress off of your back.
• Now perform a quad set by tightening your quad and lifting your leg up with the knee straight.

Straight Leg Raise Hip Abduction

• Lie on your side with your injured knee.
• Bend your bottom knee and keep your affected leg straight.
• Now lift your affected leg straight up.
  • This exercise works on your hip and outside leg muscles

Straight Leg Raise Hip Extension

• Lie on your stomach and lift your injured knee up while keeping the knee straight

Straight Leg Raise Hip Adduction

• Lie on your affected side and bend your good leg over your affected leg.
• Now keep your affected leg straight and lift it up.
  • This strengthens your inner thigh muscles.

5. Bridge

• Lie on your back with both of your knees bent.
• Now squeeze your butt muscles and lift your hips and butt off the ground.
  • Pause at the top and then slowly lower yourself back down to the starting position.
• For added difficulty, you can add a resistance band around your knees.

6. Weight Shifting

• This exercise is great for increasing weight bearing through your affected leg.
• Start in a standing position with both your feet shoulder width apart and hold onto a sturdy surface.
• Slowly shift your weight towards your affected side.
  • You should feel the majority of your body weight through your affected leg, and then slowly shift yourself back to the opposite side.

7. Marching

• Increasing weight bearing on your injured knee is very important
• Start by standing near a sturdy surface and shift your weight to one leg and lift up the other one as a march.
• Now bring your foot down and shift your weight to the other side and march up your opposite leg.

8. Clamshell

• Lie on your side with your hip stacked on top of each other and slowly rotate your top leg up, while keeping your feet stacked on top of each other.
• You should feel your butt and hips working with this exercise.

9. Pillow Squeeze

• This exercise strengthens the inner thigh muscles.
• Start by lying on your back with your knees bent and a pillow, bolster or pilates ring between your legs.
• Now squeeze your legs together for 5 seconds and then relax.
• Repeat for 10 repetitions.
• You can buy a pilates ring for added resistance on Amazon.

10. Hamstring Stretch

• The hamstrings can get tight after surgery.
• Start by lying on your back and lift your affected leg up while keeping your knee straight.
• Hold onto your thigh.
  • Hold this stretch for 30 seconds.
• If it is too difficult to hold your leg up you can perform this exercise with a towel or stretch strap as shown in the picture.

11. Calf Stretch

• Calf pain after knee surgery is very common.
• It can be due to walking on a bent knee or due to a lack of knee extension range of motion.
• Start by standing facing a wall.
  • Place the leg that you want to stretch behind you.
  • Keep your back leg straight and your front leg bent.
  • Now lean forward while pushing your back heel down into the ground.
• You can also stretch your calf while sitting by placing a towel, strap, or sheet around the bottom of the foot and slowly pull your ankle towards you.
  • Hold this stretch for 30 seconds.

Weeks 3-6

During weeks 3-6 of your ACL recovery you can begin to perform more advanded strengthening exercises, single leg exercises and progressive squats. These exercises include 12. Hamstring Curls 13. Step Ups 14. Min Squat 15. Wall Squat 16. Single Leg Bridge 17. Bridge With Hamstring Curl on Physioball 18. Single Leg Balance.

12. Hamstring Curls

• It is important to note that if a hamstring autograft was used, you should not perform any resisted hamstring exercises for the first 6 weeks.
• Start by standing and holding onto a sturdy surface.
• Now Slowly bend your knee towards your butt.
• Once you have bent it as much as you can, then slowly straighten the knee until you are back at the starting position.
• You can also perform this exercise by lying on your stomach with your knee straight and slowly bending your knee
• Be sure to control this movement and do not just let gravity bring your leg back.

13. Step Ups

• Start with a low step around 2 inches in height.
• Step onto a step with your injured knee while using a sturdy surface for support.
• Now step back down to starting position.
• Perform this exercise 10 times by leading with your affected knee.

14. Mini Squat

• Stand while holding onto a sturdy surface and bend both of your knees.
• Try to maintain equal weight bearing on each leg.

15. Wall Squat

• Stand with your back resting against the wall and your feet about a 1 foot away from the wall
• Slowly slide yourself down the wall to no more than 60 degrees.
• Now push back up through your legs maintaining equal weight bearing on both legs until you are in starting position again
• For added difficulty you can also perform this exercise with a physioball behind your back and on the wall.
• You can buy a physioball here.
• As an Amazon Associate I earn from qualifying purchases.

16. Single Leg Bridge

• Start by lying on your back with your injured knee bent and on the floor.
• Now squeeze your butt and abdominal muscles and lift your butt off the floor while keeping your other leg straight and off the mat.
• For added difficulty, you can add ankle weights.

17. Bridge With Hamstring Curl on Physioball

• Start on your back with your legs straight and your heels resting on top of a physioball.
• Now squeeze your butt and abdominal muscles and lift your butt off the floor.
• Bend both of your knees and pull the ball towards your butt and then slowly straighten your knees until your legs are straight in the starting position.

18. Single Leg Balance

• Start by standing on one leg by a sturdy surface and try to fully weight bear on your affected knee.
• Start with 10 seconds and slowly progress to 30 seconds as your balance and strength improves

Week 7-8

During this phase, you can start incorporating proprioception exercises into your exercise program. You can also start to progress the resisted exercises. These exercises include 19. Leg Press 20. Chair Squat 21. Lateral Lunge 22. Single Leg Romanian Deadlift 23. Slide Board Lunges 24. Monster Walks With Resistance Band 25. Side Steps With Resistance Band 26. Step Up With March 27. Step Down 28. Single Leg Squats 29. Single Leg Wall Slides.

19. Leg Press

• This exercise is a great exercise to strengthen your quads and work on your eccentric control.
• Start with your feet hip width apart on the machine and push out until your legs are straight.
• Now slowly bend your knees until you are in the starting position again.
• Control is the key in this exercise!

20. Chair Squat

• Start with your feet hip width apart and slowly squat to the chair without using your hands.
• Tap your butt on the chair, and without sitting down start to stand back up to the starting position.
• If this feels too easy you can perform this exercise with a staggered stance with your affected leg slightly behind your other leg.
• This will put more weight on your affected knee.

21. Lateral Lunge

• Start with your feet hip width apart and take a large step to the side and perform a side lunge.
• Now push back up from your outside foot and return to starting position.

22. Single Leg Romanian Deadlift

• Start by standing on one leg with your back upright.
• While keeping your knee with only a slight bend, start reaching forward.
  • You will continue this until your opposite leg is parallel with the floor.
• Begin by performing this exercise to a smaller range and stand next to a sturdy surface in case you need assistance with balance.

23. Slide Board Lunges

• This exercise is great for muscle strength, control and balance.
• Start with your injured knee flat on the ground and place your other foot on either a sliding board or a small towel.
• Now perform a forward lunge, side lunge and backwards lunge by sliding your foot out in each direction.
• Each time return to the starting position.

24. Monster Walks With Resisted Band

• Place a resistance band around your knees and get in a mini squat position.
• Maintain this mini squat position the entire time and start walking forward while keeping your knees out and the resistance in the band tight.
• Take 10 steps forward and 10 steps backwards.

25. Side Steps With Resisted Band

• Place a resistance band around your knees and get in a mini squat position.
• Now take steps to the side, making sure to keep resistance in the band the entire time.

26. Step Up With March

• This exercise is similar to the step up in the previous phase, however this is a progression and requires more dynamic balance and leg strength.
• Take a step up onto a step, leading with your affected leg.
• Now lift your other leg up and drive it past your other foot.
• It should look as if you are performing a march in the air.

27. Step Downs

• This exercise is great for eccentric quad control.
• The stairs are one of the most challenging functional activities to perform post acl surgery.
• Stand on your affected knee with your other knee straight out in front of you.
• Slowly bend your knee and step down.
• Do not allow your knee to save in or to perform this exercise with a lack of control.

28. Single Leg Squats

• This exercise is progression from the two legged squat.
• You can perform this with either a sturdy surface like a parallel bar or kitchen counter or trx straps.
• My preference is to perform this with trx straps because it provides stability while also still challenging your balance.
• Stand on one leg and slowly bend your knee.
• Do not allow your knee to cave inward and only perform this exercise to a tolerable depth.

29. Single Leg Wall Slides

• Perform this exercise like the previous two legged wall slide.
• Make sure to not let your knee save inward and to perform this exercise in a pain free range.

Weeks 9-12

• During this phase, you can start performing plyometrics submax specific training
• This may include two legged and single legged jumps.
• Start with very small movements and stand near a supportive surface like a parallel bar or trx strap before progressing to more difficult jumps.

3-5 months

• This phase is the return to running phase.
• The exercises in this phase will focus on agility and multiplane sport-specific plyometrics.
• This may include the use of an agility ladder to perform jumps or agility exercises.
• The goal of this phase is to target the exercises to whichever sport you are trying to return to.

6-9 Months

• This phase is the return to sport phase and in my opinion the most exciting phase!
• You are now able to perform hard cutting and pivoting movements around the 7 month time point
• Typically you can return to non contact practice during this time and progress to full practice into all sporting activities at 9 months
• Again, the rehabilitation process will vary for everyone so listen to your body and to your surgeon and physical therapist.

Core ACL Strengthening Exercises

These core strengthening exercises can be performed during any phase of the acl rehabilitation process. Core strength is very important in ACL injuries and in preventing future injuries. These core exercises include 30. Front Plank 31. Side Plank.

30. Front Plank

• Start this exercise with your forearms flat on the ground and your toes on the ground.
  • Try to bear even weight between both legs.
• If this is painful on your knee perform a plank with your affected knee raised above the ground

31. Side Plank

• Lie on your side with your forearm on the ground.
• Now tighten your abdominal muscles and lift your hips up so your spine is in a straight line.
• Start by holding this position or 20 seconds.

Non Surgical ACL Strengthening Exercises

• If you have opted for a non-surgical ACL approach then your ACL rehabilitation will most likely have less restrictions overall.
• This is good news because you can gain your strength back faster, however you must be cautious because if you do have a partial tear you do not want to make it worse by pushing yourself too hard too fast.
• Just like with surgery, it is important to gain full range of motion first.
• You can perform any of the previous exercises mentioned in this article if you have not had surgery.
  • Just be sure to listen to your body and stop if you feel pain or instability in your knee.

Summary of ACL Strengthening Exercises

You have just learned about the best exercises to perform after ACL surgery. I know first hand how long of a recovery process an ACL injury can be.

These ACL strengthening exercises will improve your knee strength, mobility and get you back to the activities that you love! Most importantly these acl strengthening exercises will prevent you from re-tearing your ACL again.

For more ACL exercises you can find 15 Fantastic ACL Physical Therapy Exercises To Rehab An ACL Injury here.