What can you do to strengthen your knee 6 months post-ACL surgery?

Six months ago you had an ACL reconstruction. After surgery, you were walking around with a knee brace and crutches. Several weeks later, you started physical therapy.

It hurt to bend and straighten your knee for months and you probably wanted to skip your physical therapy appointments to avoid the pain. But, you pushed through the pain and your knee is feeling much better now.

Currently, you finished physical therapy and your knee is not where you want it to be. Before surgery, you were running, playing sports, hiking, and you didn’t have any fear of your knee giving out on you.

Now, you are reluctant to start running and returning back to your normal workout routines and activities. The rehab process can take 1-2 years after an ACL surgery; however, most people stop physical therapy too early resulting in an increased risk of getting another ACL tear.

We understand where you are coming from and where you need to be. At this point, the smart decision is to continue your recovery process with a post-rehab program to feel confident that you won’t tear your ACL again.


Why should you continue rehab 6-months after an ACL surgery?

Approximately, 79% of those who have a surgical repair of their ACL develop osteoarthritis in their knees and 20% tear their ACL again within 2 years after their surgery.

Here are a few factors that may contribute to another ACL tear:

  • Improper running or jumping mechanics
  • Weakness in the hamstrings, quadriceps, and glutes
  • Poor balance and coordination
  • Lack of sport specific strength training
  • Decreased knee motion

If we were to test your knee with jumping, running, and squatting, how well would you perform?

Could you squat with 25 lbs weight plates on the barbell 10 times? Could you jump off a 1-foot box and land 10 times without getting knee pain?

First, your doctor would need to clear you for jumping, running, and squatting. After your doctor clears you to perform these activities, you need to practice these activities to improve your performance.

After you practice, you need to practice more. It’s an unrealistic expectation to prevent another ACL tear and feel confident again without practicing the activities you wish to participate in.

Unfortunately, most people end rehab too early consequently jeopardizing the success of their ACL surgery. In addition, ending rehab early can lead to premature osteoarthritis of the knee.

Rehab 6 month to 1-year after an ACL surgery is critical for the ACL graft to heal properly. During this time, insurance companies usually stop covering physical therapy visits.

However, at 6 months post-ACL surgery, you still have impairments in your knee function. The ACL is still healing at 6-months. In fact, studies have shown that the ACL is still healing 1-year after an ACL reconstruction.


Think about the trauma to the ACL during the past 6-9 months. The ACL was torn then it was replaced with the ACL from a cadaver or a graft from your patellar and hamstring tendons.

The grafts were used to reconstruct your ACL and your new ACL was drilled into your bone. The ACL needs to fully attach to the bone.

If you place too much stress on the ACL too soon, then it can rupture again. Therefore, you want to learn how to minimize stress to the ACL to prevent another ACL tear.

Why is a post-rehab essential to reaching your short and long-term goals?

An ACL injury prevention program can reduce the risk of ACL tears in females by 52% and by 85% in males.

Why is the percentage higher in females?

The Q-angle is higher in females than males. The Q-angle is a measure of the position of the knees in relation to the hips. Anatomically, female hips are designed to bear children; therefore, the hips are wider than males.

Consequently, the knees are closer together in relation to the hips resulting in the knees caving inward. There are additional factors that play a role too. This explanation is an over-generalization, but it conveys the general idea why females have a higher risk of ACL tears.

The statistics show that ACL tears are harder to prevent in females; however, both males and females can significantly reduce their risk of tearing their ACL with an ACL injury prevention program.


An ACL injury prevention program and a post-rehab program 6 months post-ACL surgery are very similar.

Both programs will focus on the factors listed above that may contribute to an ACL tear. For example, both programs consist of exercises to:

  • Improve running or jumping mechanics
  • Increase strength in the hamstrings, quadriceps, and glutes
  • Improve balance and coordination
  • Incorporate sport specific strength training
  • Increase knee motion

In the short-term, a post-rehab program will help you get back to the gym or field sooner. You’ll be able to return to your favorite activities without aggravating your knee pain or placing the ACL at risk of injury.

In addition to the immediate benefits of getting back to playing sports, a post-rehab program will help to minimize the development of excessive arthritis in your knees.

Statistically, those who have an ACL or meniscus surgery will develop more arthritis in their knees compared to someone who didn’t have a surgery or tear. If the cartilage in the knee wears out, there will be less shock absorption to support the knee joint.

Previous knee injuries earlier in life can lead to advanced arthritis later in life. Unfortunately, total knee replacements have been on the rise in in the United States.

We want to help you avoid these negative consequences by coaching you through a post-rehab program.

How can you return to playing sports safely without getting another ACL tear?

A post-rehab program will help you return to normal activities sooner. For example, you may want to start playing sports again after an ACL surgery. Before returning to playing sports, you need to meet specific criteria.

In a post-rehab program, a physical therapist will have you perform a series of functional tests for both knees. Measurements of each knee are taken. The measurements of the ACL repaired knee must be within 90% of the healthy knee.

For example, one test may be the Y-balance test. In the Y-balance test, you reach back as far as you can to the left and right with your health knee while stabilizing all your body weight on the knee with the ACL repair. The test would be repeated for the healthy knee.

The distanced reached with the ACL repaired knee should be within 90% of the distance reached with the healthy knee. The Y-balance test measures strength, coordination, and balance.

You must demonstrate adequate strength, coordination and balance to return to sports safely. A premature return to sports may lead to another ACL tear.


Surprisingly, those who return to sports too early, also have an increased risk of tearing their non-surgical knee. The non-surgical knee compensates for the weakness in the ACL repaired knee and can tear from excessive demands placed on it.

Ideally, both knees should be strengthened with rehab exercises for the next 1-2 years after an ACL tear if you want to prevent another ACL tear.

What are your next steps?

Insurance companies will not reimburse for 1-2 years of physical therapy after an ACL surgery; therefore, your next step is to begin a post-rehab program for a structured strength training program that will hold you accountable to your recovery.

For 6 months or longer, you have worked hard to rehab from your ACL surgery. Don’t stop now. Continue your recovery for another 6 months to 1 year to maximize the health of your knee.

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