In this blog, I teach you everything you need to know about Phase 1 (0-8+ weeks) of ACL rehab, also often referred to as the Early Stage.
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Phase 1 Goals of ACL Rehab
Aside from protecting the newly reconstructed ACL graft, there are 5 primary goals during Phase 1:
- Minimize Increases In Pain and Swelling
- Restore Knee Extension Range of Motion
- Restore Knee Flexion Range of Motion
- Improve Quadriceps Function
- Normalize Walking
Focus on Function, Not Time
Throughout Phase 1, and throughout the entire rehab process, you should focus on your function, not time.
In the title of this blog, I suggested that Phase 1 will last from roughly 0 to 8 weeks. That timeline might be aggressive for some individuals and conservative for others, but it should be realistic for the majority of people reading this blog.
I only say this because I truly care, but there are no participation trophies in ACL rehab. You don’t get to run on a swollen knee because a certain amount of time has passed. You have to earn the ability to perform more difficult tasks. This is meant to minimize setbacks, reduce your risk of reinjury, maximize long-term performance, and provide you with the confidence needed to return to your desired sports and activities.
Don’t stress too much about timelines. Don’t compare yourself to others. Focus on your function because your progress will depend on your symptoms, your pre-operative function, and a variety of other factors, such as the type of surgery performed. For example, if you had an ACL reconstruction and meniscus repair, your initial recovery is likely going to be slower because of restrictions provided to you by your surgeon to allow for appropriate healing. Similarly, if you had a hamstring graft, the introduction of hamstring strengthening will likely be delayed.
For that reason, this information is not meant to replace a consultation with a physical therapist or overrule any information provided to you by your physical therapist or surgeon.
Goal #1: Minimize Increases In Pain and Swelling
This is the most important consideration after surgery. Pain and swelling are a normal part of the early rehab process, but it is your responsibility to minimize unnecessary increases in pain and swelling when possible.
There are 2 simple ways to facilitate this:
- Use your crutches as long as necessary. Not using your crutches as instructed by your surgeon or physical therapist, or rushing off of them too soon, can actually delay your progress by increasing pain, increasing swelling, and contributing to a compensatory gait pattern. Being able to walk without crutches is a product of good rehab and is dictated by your function, not time or personal preference.
- Don’t overdo it. Early on, you don’t want to spend too much time walking or being on your feet. Excessive activity can increase pain and swelling.
Following this simple advice will make the rest of your rehab significantly better. Less pain and swelling make it easier to regain your range of motion, improve your quadriceps function, etc.
What about a knee brace?
- Not every surgeon will prescribe one, but a brace is meant to provide stability, protection, and limit unwanted motion. However, it doesn’t offload the knee the same way that crutches do. So use your brace as instructed, but understand that it’s not meant to be a replacement for crutches.
What about ice, compression, and elevation?
- You can do all of these things as often as you want, especially if they help get you off your feet in the first couple of weeks.
Your rehab exercises can also contribute to reductions in pain and swelling. For example, ankle pumps and quad sets (an exercise I’m going to discuss shortly) can be performed any time you’re sitting or lying down.
The last thing I want to mention in this section is that if you feel like you’re experiencing an unusual amount of pain, swelling, redness, or drainage from the surgical site, or you’re feeling unwell, communicate that information to your healthcare provider.
Goal #2: Restore Knee Extension Range of Motion
Although I said not to stress about time, this is a top priority because the longer you wait, the harder it is to get back. You need to be diligent with this aspect of your rehab as early as possible.
There are two primary ways to improve knee extension:
1. Prop your heel for 10-15 minutes, 4-6 times per day to accumulate at least one hour of total time. The position might be uncomfortable, but it should not be unbearable.
If you’re lying on your back or sitting up, it’s preferable to be on a firm surface like the floor.
You can also do this in a chair if you can prop your leg on another chair or object.
Over time, you can add a light weight to increase the stretch if needed.
Your body’s natural tendency is to flex the knee, so you need to commit to this process and allow yourself to get comfortable resting your knee into an extended position. At the end of each 10-15 minute duration of passive knee extension, you can perform a minute of patellar mobilizations. This just involves moving the kneecap slowly in different directions.
2. Quad sets, all day, every day. Straighten your leg as best you can, then squeeze your quads (the muscles on the front of your thigh) by trying to push the back of your knee into the floor. Hold for 10 seconds, relax, and repeat for 10 repetitions.
Initially, if this is painful and difficult, you can place a small towel under your knee for comfort and feedback.
However, as I just mentioned, your body’s natural tendency is to keep the knee flexed so you wouldn’t want to rely on this strategy for an extended period of time.
To progress the quad set, you can incorporate the heel prop I just discussed.
To increase the range of motion even further, use a strap and pull up on your foot to add a calf and hamstring stretch.
You can also do a similar variation while seated at your desk, at the dinner table, on the couch, etc. Straighten your leg, squeeze your quads for 10 seconds, relax, and repeat.
I cannot overemphasize the importance of doing quad sets as frequently as possible. One well-known ACL protocol recommends doing up to 1,000 repetitions per day. This is one exercise you cannot overdo. Also, make sure each repetition is focused and intentional. Contracting your quads is extremely difficult after surgery, so avoid being distracted or scrolling social media when doing them.
The end goal should be to get your knee extension range of motion equal to your uninjured side (completely straight or some degree of hyperextension).
One thing you can look for is a “heel pop,” which refers to the heel slightly coming off the ground when performing a quad set.
Goal #3: Restore Knee Flexion Range of Motion
Thankfully, this is typically easier than restoring knee extension, so it doesn’t require the same volume of exercise. As a reminder, you may have restrictions to limit your knee flexion to no more than 90 degrees initially if you also had a meniscus repair.
There are a lot of ways to improve knee flexion, but these are my two favorite:
1. Heel slides. While lying on your back, slide your heel toward your butt, hold the end position for a few seconds, slowly straighten your knee, and repeat.
To assist the movement, wrap a towel or strap around your foot and slowly slide your heel toward your butt while gently pulling on the towel or strap to help bend your knee further. Heel slides can be performed for 10-20 repetitions, several times throughout the day.
2. The second option, at some point in your rehab, is a recumbent bike. Position the seat further back and begin with partial revolutions, moving your knee in and out of as much flexion as tolerable. Once you’re able to complete full revolutions, gradually move the seat forward to expose the knee to more flexion.
You can also follow a similar progression on an upright bike. Start with the seat at a higher level and do partial revolutions. As your mobility improves and you can complete full revolutions, move the seat down to further challenge and increase your knee flexion.
For either option, you can start with 5-10 minutes and gradually do more over time.
Once again, working on knee flexion might be uncomfortable, but it should never be unbearable. This is not something you have to force.
The end goal should be to get your knee flexion range of motion equal to your uninjured side, which usually involves getting your heel to your butt or close to it.
Goal #4: Improve Quadriceps Function
The quads effectively shut down after an ACL Reconstruction secondary to pain, swelling, and the nature of the surgery itself, including any associated nerve blocks.
Two strategies to combat this are methods we’ve already discussed:
- Minimizing unnecessary increases in pain and swelling
- Quad sets as frequently as possible. When you’ve restored your knee extension range of motion and your function has improved, you can perform standing quad sets with external resistance by using a ball against a wall or a band anchored to an object.
An important milestone that you’ll need to achieve is the ability to perform a straight leg raise without lag. “Lag” refers to a slight bend in the knee. Quad sets will help you achieve this milestone.
When you eventually perform straight leg raises, you’ll likely be asked to perform 3 sets of 10-20 repetitions daily.
However, it’s important to keep in mind that the primary action of the quadriceps is knee extension. Therefore, straight leg raises are not effective for improving quadriceps function beyond your very basic needs since they become more of a hip flexor exercise.
More needs to be done, but squats are not enough. Research by Sigward et al in 2018 found that people unknowingly perform compensations to offload their quads during squats for at least 5 months after surgery.
For this reason, I highly recommend isometric leg extensions between 90 and 60 degrees of knee flexion using a machine, strap, ball, or some other immoveable object.
I think it’s one of the most important exercises to perform as quickly as possible and throughout the entire rehab process. Leg extensions might not look “functional,” but the quads are the only muscles capable of extending the knee. There is no way to compensate.
Aren’t they dangerous? No. Not only is there no research to suggest this, there is research to refute this. However, the purpose of this blog isn’t to convince you otherwise or defy any precautions provided to you by your healthcare provider.
Plus, I am only recommending isometric leg extensions between 90 and 60 degrees of knee flexion. Isometrics in this range of motion place zero strain on the ACL.
I’ll repeat it one more time – isometric leg extensions between 90 and 60 degrees of knee flexion place zero strain on the ACL. That’s less than walking, squatting, or any other activity you might eventually do.
Aim for 3-4 sets of 30-45 second holds. As with everything else, they should be tolerable. You don’t need to push all out. I recommend trying them on your unaffected side first to get a feel for the movement. I also recommend that you gradually ramp up and down your effort, so you don’t accidentally get a spike in symptoms. This will take practice to get right, but you can do isometrics for the entire 8 weeks (or longer if you prefer) as they’re effective at improving strength and hypertrophy, while reducing any worry you might have about strain on the ACL.
If you’re working with a physical therapist, they may use Blood Flow Restriction (BFR) training and/or Neuromuscular Electrical Stimulation (NMES) in conjunction with leg extensions or other exercises you are doing as a means of improving quad function.
Goal #5: Normalize Walking
If you’ve managed your pain and swelling, slowly weaned off your crutches, restored your knee extension range of motion, and have been actively working on your quadriceps function, normal walking should hopefully come naturally. There are exercises you can do to improve your tolerance to putting all of your weight on the affected leg, though.
To start, you can practice weight shifting onto that side.
Then you can progress to single leg balance. You might start by looking at yourself in a mirror, but you want to eventually take away that visual feedback. When you’re ready, you can perform single leg balance with your eyes closed, with head turns, on an unstable surface, or while multi-tasking like brushing your teeth or juggling a ball.
There’s no limit to what you can do as long as it’s safe and tolerable, but stick to the basics at first by building up to 3 sets of 60 seconds on a single leg comfortably.
Marching over hurdles forward, backward, and sideways is another great option.
Lastly, backward walking can help reinforce terminal knee extension in weightbearing. Like with everything else, you can begin with a few minutes and gradually add more time.
Programming
I’ve provided a lot of information up to this point, and there’s still more to discuss, but programming these exercises doesn’t need to be overly complicated. You just need to do the basics well and often.
Assuming no restrictions, here are the 3 movements you should be doing daily:
- Heel prop for 10-15 minutes, 4-6 times per day to accumulate at least one hour of total time. At the end of each 10-15 minute duration of passive knee extension, you can perform a minute of patellar mobilizations.
- Quad sets for 10 repetitions of 10 second holds. I cannot even provide an upper limit for this exercise. You should be doing it as often as possible.
- Heel slides with a strap for 10-20 repetitions, at least 3-4 times per day.
If you have the range of motion, the exercise is tolerable, and you have the approval of your healthcare provider, you can also do the isometric leg extensions for 3-4 sets of 30-45 second holds.
As you progress through your rehab, your routine might start to look more like this:
- 10 minutes on a recumbent or upright bike
- Quad sets with a strap
- Heel slides through a larger range of motion
- Isometric leg extensions
- Straight leg raises for 3 sets of 10-20 repetitions
- Standing quad sets with external resistance
- Single leg balance for 3 sets of 30-60 seconds
- Backward walking or marching over hurdles for 3-5 minutes
- Heel prop with weight
Keep in mind that doing more is not inherently better if you aren’t mastering the basics and applying the same effort and intentionality into every movement you do. I understand that everyone wants to be further along in their rehab, but there is no benefit to skipping steps.
Introduction of Strength Training
Another component of Phase 1 is the gradual reintroduction of resistance training to minimize losses in muscle, strength, and function, and to help prepare you for the next phase of rehab. The number one priority here is safety. Generally that means using assistance as needed, reducing the range of motion initially, and starting with bodyweight exercises that are tolerable.
I’ll list out various exercises, potential starting points, and expected progressions, but your exact timeline will vary depending on your symptoms, function, stage of healing, surgery, and precautions from your physical therapist or surgeon.
Most people will start with mini squats and gradually increase the range of motion. A box, table, or chair is often used to limit the range of motion and normalize the depth of each repetition.
As your strength, control, and tolerance improve, you’ll likely move on to goblet squats, split stance squats, single leg squats, and/or split squats.
Higher wall sits can be progressed to lower wall sits.
Step ups are usually performed before step downs, and the range of motion of both are increased over time.
The leg press machine becomes a popular option because you can easily control the load and range of motion.
Double leg bridges, whether for repetitions or isometrics, are progressed to single leg bridges or weighted variations.
For isolated hip exercises, common options are side lying hip abduction, side lying hip adduction, prone hip extension, and the straight leg raises I’ve already discussed.
For hinging, you’ll progress from bodyweight hip hinges to weighted Romanian deadlifts to single leg Romanian deadlifts and weighted single leg Romanian deadlifts.
Strengthening the hamstrings through resisted knee flexion is an extremely important component of ACL rehab. You might start with isometrics, in which you’re digging your heels into the ground, or standing hamstring curls with a cuff weight.
And progress to hamstring curl machines, hamstring curls on a ball, and similar options.
Remember, this will be delayed if you’ve had a hamstring graft.
For the trunk, you might do planks and side planks.
Lastly, double leg heel raises on the floor will be progressed to single leg heel raises and then to single leg heel raises on a step.
I want to be very clear that this isn’t an all-inclusive list or set of progressions. I wanted this blog to focus on the basics while still providing other exercise options. When done in a safe and timely manner, these exercises shouldn’t increase pain and swelling, or take precedence over the Phase 1 goals. Comprehensive strength training will be the focus of Phase 2.
A simple framework for programming is to think about doing exercises such as these every other day, assuming you’re tolerating them well and recovering appropriately. Also, you don’t need to do every exercise I’ve listed in every training session. You might do a squat variation, a hinge or bridge variation, knee extension, knee flexion, a trunk or hip exercise, and heel raises.
Plus, you’ll still be performing the daily exercises I suggested earlier. It ends up being quite a bit.
And if that’s not enough, there are…
Additional Strength & Conditioning Considerations
1. Training the uninjured leg to maintain your strength and muscle mass. Some single leg exercise options include leg extensions, seated or prone hamstring curls, seated or standing calf raises, and the leg press. Just don’t choose exercises that put your injured knee at risk.
2. Upper body training for the same reasons, although it’s less important. This also helps some athletes keep their sanity during the long rehab process. Once again, only select exercises that you can implement safely.
3. Long duration cardio. After you’ve regained your knee flexion range of motion, you can start increasing the duration of your bike rides to improve your conditioning.
One of the biggest challenges you’ll face is…
Dealing With Doubt and Uncertainty
There’s no way to prepare for this, but I can tell you that what you’re experiencing is normal.
You might worry that you injured your knee because you have an increase in pain or swelling.
You might feel overwhelmed by the number of exercises you need to do.
You might be discouraged if you don’t accomplish your goals in the time that you expected or hoped.
This is a long journey. It’s tiring. It’s tough. There will be ups and downs. Doubt and uncertainty are normal.
Keep showing up, take it day by day, and express any concerns to your physical therapist, family members, or friends.
I want to end the blog by answering one last question…
When Does Phase 1 End? (Summary)
The phases of rehab are somewhat arbitrary. You’re not in Phase 1 one day and suddenly in Phase 2 the next day. There’s going to be overlap because these phases exist on a continuum.
However, as I stated at the start, there are 5 primary goals during Phase 1:
- Minimize Increases In Pain and Swelling
- Restore Knee Extension Range of Motion
- Restore Knee Flexion Range of Motion
- Improve Quadriceps Function
- Normalize Walking
Take your rehab and training to the next level by getting started with our 1-on-1 remote consultation and coaching services!
Want to learn more? Check out some of our other similar blogs:
How To Grow Your Quads, ACL Rehab, How To Perform Nordic Hamstring Curls
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