ACL Rehabilitation Timeline: Month Four

Here we go, everyone: month 4 of ACL rehabilitation!

As we’ve mentioned in our previous installments, rehabilitating from an ACL injury is a long and challenging journey — but it’s one you can absolutely conquer with the right knowledge and determination.

Which is exactly what this series is all about! So far, we’ve covered the expectations, goals, and general progressions of the first few months after an ACL injury (each of which you can check out here: prehabilitation, month one, month two, and month three). 

And there’s no stopping us now, so read on to understand the usual expectations of your fourth month of ACL rehab.

Physical Therapy During Month 4

Hitting your fourth month is a pretty exciting turning point in your ACL rehab timeline. By this point, you’ll have dedicated a significant amount of time to your training and will likely have made noticeable progress.

One of the most exciting parts about the 3-4 month mark is that you’re typically given the official “okay” to get back to running — and, with the proper protocol, you’re probably in the process of improving your gait and further enhancing your body’s strength and movement. And, on top of furthering your performance, you’re also at a point where you can start practicing those sports-specific movements again!

You’ve really got the ball rolling now, so let’s keep that momentum going and dive more into the specifics behind these new rehabilitative benchmarks.

Improve Your Running Mechanics

Let’s start with the part that many athletes are aching the most to get back to: running.

A majority of athletes will start their return to running around the 12th week after surgery. Following this standard timeline, by your 16th week, you’re likely to be running anywhere between 5-20 minutes per session. And with that, you probably won’t need to ice as frequently or stretch as much to keep your knee at full range of motion.

It may not sound like a huge victory, but trust us — it’s quite the feat. (And you’ll probably feel a lot more accomplished when you actually get to live the exhilaration of running again.)

But, let’s not forget that returning to running is a gradual process. It’s imperative to ease back into it to ensure proper form for optimal shock absorption and power generation.

Gradual Process

Shock absorption is especially key here. Running with insufficient shock absorption will only increase the pressure at the cartilage under your kneecap, leading to a greater strain on the joint itself. Increased impact forces aside, you’re likely to experience increased swelling in the knee, ultimately causing a further delay in your rehab process.

In order to improve your shock absorption, you’re going to focus on improving the flexion in your hip, knee, and ankle under load. (And if that doesn’t mean much to you, it’s basically continued work on the activation and eccentric strength in your glutes, quads, and calves! Which, as you know by now, are some of the biggest focuses in your first few months.)

The tough part is that you have to work through the mental hurdle of using your knee that much. When you first start running, it’s natural to try and alleviate some of the pressure on your knee (whether you actively or subconsciously do it). Your brain will instinctively keep your hip and knee straight in order to spend as little time as possible on your injured leg, but this actually causes the inverse effect by increasing the loading on your cartilage and knee joint… and that’s all bad.

Hence, it’s essential that you practice running and relearn how to load your gluteal and quadricep muscles instead of your joints.

All this isn’t to say that you shouldn’t be excited to run again; it’ll just take some time and diligence to ensure a safe return. It’s best to seek a running assessment from your physical therapist, as they can help you perfect your form in the early stages of your running retraining. Your PT will lead you through key drills and focus points to help you pick up proper running form in no time!

Continue to Build Muscular Strength and Power

Okay, so strength workouts aren’t new to you at this point… but there’s still a pretty substantial upgrade in intensity.

Because the past few months have primarily been focused on establishing a solid foundation for your strength work, now’s the time where all that effort pays off: in month 4, you’ll start taking on heavier lifting workouts!

This is often the time where you’ll start practicing some Olympic lifts, like heavy squats and deadlifts. Whether you’re familiar with them or not, they’re pretty vital as you progress through your strength training.

Lifts are a form of multi-joint or compound exercise that helps improve your muscle development on a more global level. Compound exercises focus on working out more than one major muscle group at a time, which is especially ideal for preparing your body for more complex, sport-like movements such as cutting and jumping.


Plus, with proper form and the right amount of weight, Olympic lifts help stimulate the release of muscle-building hormones like growth hormone and insulin-like growth factor (both of which will “cue” the body to rebuild stronger muscles). These hormones are absolutely vital for gaining true, objective strength. 

But of course, as with any major progression in your ACL rehab, don’t jump straight into newer and more intense work. Make sure to consult with your physical therapist about proper form, when and how to add these workouts, as well as how to progress the weight on a steady schedule to ensure you’re promoting healthy growth every week.

Begin Agility Training

Now here’s one of the newest (and maybe most exciting) additions to your rehab: agility training. 

You’re finally ready to start easing back into those sports movements again, and as the original author of this series can vouch for: it’s an awesome feeling. 

As you get back into practicing agility and the basics of these movements again, you’ll be working at about 25% of your normal game speed. We know, we know; a part of you is ready to put in as much effort as you can, but that’s not the name of the game, here. The purpose for agility training is to build better speed and quickness to apply to all your sport-specific movements, but if there’s anything we’ve learned about rehab, it’s that the end goal comes with diligent, gradual practice.

Besides, after a few months of rebuilding your athletic capacity from scratch, you don’t want to dive headfirst into anything like you used to. (Especially not at the risk of undoing all your hard work so far.) At this point in your rehab, you’re going to focus on relearning all the basics behind common movements like lunges, lateral shuffles, and deceleration — all of which are absolutely vital in-game. 

Agility Training

As you start doing sport-specific movements, your inner athlete will feel elated, and you’re probably going to be tempted to release the shackles of your protocol and jump back on the field.

Unfortunately, your ACL is far from ready to do so. These movements place a higher demand on the ACL, so be sure to ask your PT for ideal form and mechanics to learn ideal movement patterns. It takes a certain mental strength to ensure that you don’t subconsciously convince yourself that you can take on more than you should…

Which brings us to an important point about how to manage the mental forefront during this phase of your recovery timeline.

Turning Frustration Into Motivation

As much as your progress these past few months is stellar and worth celebrating, there’s a good chance that you’re feeling more frustration than you’d like. After doing countless bridges, squats, lunges, and fire hydrants, you still can’t get back to playing yet… and while you can, of course, appreciate all the strides you’ve taken so far, it doesn’t quite eliminate the thought that rehab feels like it’s taking forever.

It’s easy to get caught up in that mentality while pondering (or dreading) how much rehab you still have left to cover.

So here’s a little trick to shifting your perspective: remind yourself that only 4 months ago, you were still in a brace, using crutches, and struggling with just trying to sleep through the night without any pain. And now, you’re most likely pain-free (or soon-to-be!) and feeling like your knee is doing well.

In addition to all you’ve accomplished, you’ve also got a sort of mental “leg up” on other athletes who haven’t endured debilitating injury. That might sound odd or counterintuitive, but think about it this way:

As you’re running incrementally longer distances, those 5-20 minute runs are now exhilarating in a way that they never would have been before your injury. You can finally work up a real sweat again from your exercise, and it’s a kind of thrill that you never would have expected to enjoy. Plus, increasing your training by increments may make those smaller drills feel less tedious and more focused when you understand how much of an impact they make in the bigger picture.

It’s a game-changer… but in a good way.


Your perspective is now forever changed. Before the injury, you (of course) enjoyed your sport, but now you get to feel the joy behind the ability and the true effort behind it — and that’s not something every athlete can recognize. 

You now have something that very few other athletes have, that “something” that drives you beyond what you thought was possible. It isn’t something you can teach or learn: it’s the “why” behind your fervor for the sport.

After injury, you realize you had something to lose; you lost the ability to do what you loved. But, what you gained was undeniably valuable: the opportunity to physically test and push yourself to the limits for the sake of proving that you have what it takes.

Goals for Month 4 of ACL Rehabilitation

Not too shabby for where you were just a few months back, right? (And as people who have directly witnessed numerous ACL rehabilitations, we can confidently say that it is some darn impressive progress, and never ceases to be inspiring!)

Of course, the specifics behind your individual training plan may vary from another athlete’s, but here’s a quick summary of some of the general expectations you can look forward to in month 4:

  1. Improving your running — by this point, you’ll have already gotten your feet wet with returning to running, and now’s the time where you start wading further into the metaphorical pool! You’ll be focused on improving your running form while also increasing your overall speed and distance.
  2. Further strengthening those muscles — yes, you’re still going to be working those quadriceps, hips, and calves. (We don’t want all your hard work to go down the drain, now!)
  3. Adding power workouts — this will be a key aspect to making sure your large muscle groups are not only strong, but also familiar with FAST and POWERFUL activation and movement similar to how they would function in-game.
  4. Beginning agility training — similarly, agility training is an important facet for easing your body back into sports-like movement. Even if you aren’t moving at your fullest capacity yet, it’s a pretty big milestone to hit this early on in your timeline.
  5. Testing for movement biomechanics — another cool thing to look forward to! This month will be the first time your PT will assess those sport-specific movements to determine what biomechanical necessities you need to address moving forward.

It’s some pretty exciting stuff for a rehabilitating athlete! There’s still lots to take on and relearn, but remember: it’s about the long haul. Putting in the time to reeducate yourself and retrain your body will pay off immensely down the road, so stick with it, warrior!

On to Month 5!

And there you have it! Month 4 of your ACL rehab, explained.

It may seem daunting that you’re only a fraction of the way through your recovery timeline, but your determination has already taken you this far into your recovery. In the same way you’ve kept positive and stayed motivated in the early stages of rehab, you can harness the power of your progress to keep that momentum going.

Don’t discredit yourself and the progression — you are resilient, you are capable, and you’re well on your way to coming out the other end stronger (both literally and figuratively). 

Keep on keeping on, fellow athlete, and we’ll see you for our next installment!

By Dr. Kevin Vandi DPT OCS CSCS

Dr. Vandi is the founder of Competitive EDGE Physical Therapy — with his background in physical therapy, orthopedics, and biomechanics, he is a highly educated, compassionate specialist. Using state-of-the-art motion analysis technology and data-driven methodologies, Kevin has assisted a wide range of clients, from post-surgery patients to youth and professional athletes. When he isn’t busy working or reading research, he spends his time with his wife Chrissy and their five wonderful children, often enjoying the outdoors and staying committed to an active lifestyle.

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