How To Optimize Recovery From ACL Surgery: Weeks 2-6
If you’ve made it to 2 weeks post-surgery, congrats. Hopefully you’re off pain meds, you’re able to walk without crutches (and you’re a rockstar if you can walk without looking weird), your leg muscles are working decently, and you’re getting back to some sense of normal life. (Not this far into rehab? Check out my post about optimizing rehab during the first 2 weeks). This is where things start to get fun. While we can’t be very aggressive with your rehab yet, we can start adding in a couple new tools and exercises to continue to progress you back to returning to sports. In this post, I will discuss proven strategies to maximize your improvement during this phase and keep you on the right path to return to doing the things you love to do.
Optimization Strategies
As important as knowing how to optimize your improvement during phase 2 of your rehab (2-6 weeks post-surgery) is knowing when to progress to this stage. There are some commonly accepted criteria you should hit before progressing to phase 2, including:
- Good quadriceps control, indicated by perform 20 straight leg raises without any bend in the knee
- Good motor control, indicated by a relatively normal gait pattern (also a test of muscle function)
- Good range of motion: full knee extension and 90-110 degrees of active flexion
- Minimal swelling and pain
In most cases, once you have reached these criteria you are ready to progress. One thing to note: if you had surgery on your meniscus as well, there are additional precautions in addition to what I write about in this article, plus your rehab will probably be a little slower.
Below are the areas that I believe will optimize your improvement during phase 2 of recovery from ACL surgery.
1. Maximize Leg Strength and Muscle Mass
The most important component regarding long-term recovery from ACL surgery is maximizing strength and muscle mass in the leg (muscle mass is a good, but imperfect, proxy for comparisons of muscle strength between legs). Research shows that a staggering percentage of individuals never come close to recovering the quadriceps and hamstring strength that they had prior to surgery – which in almost all cases is lower than their strength pre-injury!
From my experience and from reading through the studies that have shown the best results for restoring quadriceps and hamstring strength, I believe the biggest reason individuals don’t recover their strength is because their strength training is under-dosed, meaning the resistance they are working against is not adequate to produce the necessary improvement in strength and muscle mass that we are looking for. Most physical therapy clinics don’t even have a leg press machine that you can add weights to, and almost no physical therapist is going to tell you go to the gym and do a relatively high weight on the leg press or hamstring curl machine due to liability risks. I can understand why the recovery of strength is so abysmal, but it’s a huge problem.
Quadriceps
What’s my strategy instead? Let’s start with the quads. One of the best studies I have seen took 28 patients post-ACL surgery and started them on a strength training program as soon as 2 weeks post-surgery. Specifically, the patients had to:
- be able to stand on the surgical leg for at least 5” without support
- demonstrate active range of motion of 0-90 degrees
- perform repeated straight leg raises without the knee bending (called an extensor lag)
- have minimal swelling with activity
- demonstrate good glute and knee flexor activation
Once patients met these criteria, they began a strengthening program that consisted of performing unilateral leg presses 2x/week for 8 weeks. Patient performed 3 sets of 10 reps at 70% of their predicted post-surgical 1 rep max (1RM), with the weight adjusted as appropriate based on their performance during each session. At the end of the study, which corresponds to between 10-12 weeks post-surgery depending on when the participants met the criteria to begin this program, the subjects’ knee strength improved 85% compared to when they started the program and was approximately 90% as strong as the un-injured leg was at the start of the program (the un-injured leg became way stronger during the course of this training program as well, so the injured leg was only 70% as strong as the un-injured leg at the end of the study, which is still pretty good).
This leg press program isn’t without some drawbacks. As someone currently going through a similar program following ACL surgery, I can tell you that performing 70% of your 1RM for 10 reps HURTS. This is especially true if you had a third of your patellar tendon taken out for the graft, because that’s the tendon all of this knee extension force is being transmitted through. Trust me, this program works, but it’s not fun.
Blood Flow Restriction
However, I kind of buried the lead on this study; it was actually a study comparing high-resistance training (the protocol outlined above) with low-resistance training combined with blood flow restriction (BFR). In the BFR arm of the study, the participants performed the leg press at the same frequency, but with a 30-15-15-15 rep scheme at 30% of their 1RM, with an occlusion pressure of 80% (if that parts doesn’t make much sense, check out my post about BFR here). This group experienced nearly identical improvements in quadriceps strength as the high-intensity group, but with significantly lower pain scores. If you have access to BFR cuffs, I think they are an excellent way to get a lot of the same improvements as high-intensity exercise during this phase but with way less pain.
Hip/Gluteal Muscles
Alright, that was a long diatribe on the importance of quad strength following surgery. Let’s take a look at another muscle group that is important: your glutes. Your glute muscles are responsible for extension and rotation of the femur (thigh bone), which is turn controls rotation forces at the knee. If you have weak glute muscles, your leg will turn in (referred to as knee valgus) whenever you do high-intensity exercises such as running, jumping, or cutting; in fact, weak glute muscles are probably one of the reasons you tore your ACL in the first place if your tear was a non-contact injury.
During phase 2, there are a variety of exercises you can perform to begin to improve leg strength. One of the most common exercises patients receive is the 4-way hip exercise, which can be performed in either standing or on the ground. This exercise is a great starting point to begin to retrain your brain to activate the hip muscles, but once you are able to perform 15-20 reps in each direction, I like to move to harder exercises. While there are some haters of this exercise, I believe that clamshells are a great way to fatigue the glute muscles during this phase of rehab – you can scale the difficulty of the exercise by changing the strength of the resistance band and the exercises will cause a minimal increase in discomfort in the knee. I also like an exercise that I call penguin walks, where you place a resistance band around or feet or ankles and waddle side to side. The attached video isn’t exactly what I want but was the closest that I could find to what I’m looking for. Instead of having your knees bent, I like to have the knees mostly straight, which allows you to actively contract the glutes throughout the exercise. Once you become more comfortable with performing squats, you can gradually bend the knees like he does in the video. Last but not least, air squats are a great exercise to begin performing during this period. I like performing TRX squats initially, since it lets you sit your weight back a little more than with a normal squat (reduces pressure on the quads and patellar tendon) and allows you to catch yourself if you hit a painful spot in the middle of the squat. I like to start with a mini squat and progress gradually as pain and strength improve.
Hamstrings
As I mentioned earlier, improving hamstring strength is also very important during this phase. Unless you had a meniscus repair in addition to your ACL reconstruction, it is typically safe to begin hamstring strengthening exercises during this phase. The easiest one to start out with is simply bending your knee (hamstring curl) when lying face down on a bed or table. If you have them, you can use ankle weights to increase the resistance, or have another person provide light resistance over your Achilles to make it harder. Personally, I found that half the difficulty with this exercise was putting weight through my kneecap, so I found that sliding down the table until my knee was just off the edge made this exercise less painful.
You will hopefully be able to easily perform this exercise early in this phase, at which point you can progress to performing hamstring curls with a machine. As with all other leg exercises during this phase, start light and gradually progress the weight. If you have access to BFR, this is a great place to use that as well.
2. Restore Range of Motion
Let’s move on to range of motion. At this point, you should have full knee extension, even if that means you have to sit with your leg propped up and cajole it a little bit until it straightens all the way out. If you can’t do that, it’s priority #1 for you before you even think about flexion.
Knee Flexion
When you’re ready to begin improving knee flexion, my favorite way of doing this is to lay on your back with your feet on the wall and slowly slide your heel down the wall until it gets tight. Your physical therapist can also help you improve knee flexion with a variety of techniques that make is less painful, so I recommend that as well.
Once you’re cleared to ride a bike, which typically occurs once you have about 110 degrees of flexion, this can be a great way to improve knee flexion. Go slow at first, and you might not be able to make a full rotation. That’s fine; even rocking as far as you can comfortably go and then releasing the pressure will help you move in the right direction. You’ll be surprised how much your knee loosens up from even 5 minutes on a bike.
Ankle and Hip Mobility
An area that’s often overlooked during this phase is ankle and hip mobility. If you recall what I was saying earlier about how your knee moving into the valgus position due to weak glutes increases your risk of injury, poor hip and ankle mobility can also put your knee into this valgus position. This phase of rehab is a great time to begin working on improving hip flexion (bringing the knee to the chest) and ankle dorsiflexion (bringing the knee over the toes) flexibility. The easiest way to improve hip flexion is to lay on your back, grab behind your knee, and then bring your knee as close to your chest as possible; if there’s still some pain in the knee with this movement, you can use your other foot to assist in lifting the foot into the air, which will help you focus on stretching your hip, rather than thinking about the pain in your knee.
Ankle dorsiflexion can easily be stretched by performing standard calf stretches in a standing position. A relevant piece of anatomy in this situation is that the calf is actually made up of 2 muscles: the gastrocnemius and the soleus. The gastrocnemius attaches below your ankle and above your knee, which means that the best way to stretch it is with the knee straight. The soleus only crosses your ankle, so the best way to stretch it out is with the knee bent. You can also perform these exercises on an inclined surface like a slant board (or if your driveway has a 20-degree angle like mine, that works too). If you can, doing these stretches in a sauna after a workout is extra effective, because the heat will improve the elasticity of your muscles.
Patellar Mobility
Another factor that can be limiting your knee motion is patellar mobility. Your patella is supposed to move along with your knee when going into flexion and extension, and if it is tight going in any direction, that can restrict your total range of motion. When extending your knee, the patella should move superiorly (toward your hip), and when flexing your knee, the patella should move inferiorly (towards the foot). During this phase, patellar immobility is likely to restrict extension more than flexion, since you likely won’t have full flexion yet, so working on moving the patella side-to-side and superiorly may help restore any missing extension.
3. Improve balance
Next up is balance. While there isn’t a lot of research on exactly how much poor balance contributes to risk of re-injury, almost all ACL injury prevention programs include balance exercises of one type or another. Research on ankle injuries has shown that individuals with poor balance are up to 4 times more likely to sustain an ankle injury; I imagine the same is true for knees as well.
Balance exercises function to improve muscle co-contraction around the joints in the leg to improve active stability of the joint. This is especially important after knee surgery because surgery and the ensuing swelling and pain cause damage to receptors in the knee joint – called proprioceptors – that are responsible for giving the brain real-time data on the position of the knee relative to the rest of the body. It’s like driving a Tesla on autopilot after an accident, but the sensors that check your blind spot aren’t working, increasing your risk of another crash (aka re-injury). The only way to restore the function of these proprioceptors is through practice.
The best way to start regaining balance is by practicing on a stable surface with the eyes open. The typical progression is to start with your feet together, then move to standing with one foot in the front of the other (tandem stance), and then move to single leg balance. Once you become proficient at any of these positions, you can begin making it harder by either closing your eyes, standing on an unstable surface such as a foam pad, or both. As you continue to improve, you can then begin standing on even more unstable surfaces like a DynaDisc or Bosu Ball and begin performing dynamic movements like squats and single leg deadlifts. It’s important to note that you need to go slow with these progressions; nothing will be worse than challenging your balance a little too much, falling, and re-injuring your leg. You can push yourself a little too far in a lot of areas of ACL rehab and be ok; balance isn’t one of them.
Aquatic Therapy
Another way you can work on balance safely in the early portion of phase 2 is by doing aquatic therapy. In addition to walking laps in a pool to improve gait mechanics, you can work on the same balance exercises as above, with the added difficulty of the natural ebbs and flows of the water.
Whole Body Vibration Training
The last, and coolest, strategy for improving balance is using whole body vibration (WBV) training. When doing WBV training, you stand on a platform that vibrates at certain frequencies, typically between 10-50 Hz, and either just try and maintain your balance or perform exercises like squats while it’s vibrating.
There is more research than I expected on using WBV training following ACL surgery. Of all the studies I found, only one of them started WBV training during phase 2, but the results were impressive. This study had participants perform 2-6 60-120” bouts of simply standing on the WBV platform between weeks 2-7 post-surgery, progressing to performing squats on the WBV platform during weeks 8-11 post-surgery. When they compared this group to the control group that performed a basic ACL rehab protocol, they found that the groups had similar knee range of motion and strength throughout the first 12 weeks of rehab, but the WBV group had significantly better dynamic balance. (If you want to learn more about WBV training after ACL surgery, you can read my more in-depth blog post here.)
I started following this protocol beginning right around 2 weeks post-surgery and noticed that I was able to walk with better mechanics and less pain once I finished the workout. Beginning around week 3, I was able to progress to single leg stance, which is certainly more challenging than balancing on stable ground, but still safe because I have support bars in front of me. If you have access to a WBV platform, it can be an easy way to get more bang for your buck when working on balance.
4. Improve cardio
You may have noticed by this point that your cardio is suffering because you haven’t really been allowed to do anything up to this point. Luckily, that’s about to change. Once you can comfortably ride a bike, you can begin to increase the speed and resistance until you’re doing full-blown bike workouts. Another option for doing cardio on a bike when your surgical leg still isn’t very comfortable with it is to use an assault bike. These are becoming more common at regular gyms, and they utilize both your arms and legs to produce power. The cool thing is that they have footrests, so you can put your surgical leg on the foot rest and just use your arms and other leg to pedal. I started doing this 4 days after my own ACL surgery and it worked great for cardio in the first couple weeks.
You can also begin using the elliptical and stairmaster during this phase. Personally, I find the elliptical to be kind of tough to do early on, and the stairmaster will not be comfortable by any means. If you decide to use these, start slow and gradually increase your speed.
One other machine that I’ve found to be valuable during this phase is the ski ergometer. The most popular one is made by the same people that make the Concept 2 rowing machine, and it’s a great upper body workout. In addition, the motion of the exercise puts you into about 30 degrees of knee flexion, which will help you become accustomed to distributing your weight evenly between your legs when performing mini squats.
Sauna
Another way to maintain your fitness is to use the sauna after your workouts. I personally like to do a cardio workout first and then jump right in the sauna so I don’t have to be in there as long to achieve the same amount of suck.
Sauna acts as an exercise mimetic by increasing your body temperature, which causes your body to work harder to get rid of that heat through breathing and sweating. This results in an increase in heart rate, cardiac output, blood pressure, and ventilation, which are all hallmarks of exercise. As long as your incisions are healed and you have no contraindications to heat exposure, daily sauna use will help you maintain your cardio and can even help with improving muscle strength if done after a workout (this is widely cited online and I think I saw a study on it in the past, but I currently cannot find any actual evidence behind this fact).
5. Nutritional Strategies
Just as nutrition is incredibly important for controlling pain and inflammation and maintaining muscle mass during phase 1 of rehab, it remains important during this phase as well.
Protein Intake
The most important nutritional component during this phase is protein intake. Our goal is to provide the body a consistent stimulus that your goal is muscle growth, and this requires a combination of exercise and food. I mention exercise because you can eat all the protein in the world, but if you’re not working on your quad activation and strength, your body isn’t going to direct resources to this area; consistently working on these muscles is vitally important.
During this phase, you can still afford a relatively high level of protein, on the order of around 2g/kg/day. One study found that athletes that consumed around 2.3g/kg/day following an injury exhibited less muscle mass loss than a group that consumed 1g/kg/day. I believe that continuing to supplement with essential amino acids (EAAs) during this period is helpful, as well as a high-quality protein powder.
Overall Food Intake
Overall food intake is also important during this phase. Following surgery, your body’s metabolism increases as much as 20% and this increased energy need continues well into this phase. It’s certainly recommended that these calories come from good fats, proteins, and carbs. It’s best to avoid seed oils (canola, vegetable, etc.) and instead choose fats like butter, avocado oil, coconut oil, and olive oil. One reason for this is that seed oils are inflammatory due to their manufacturing process, whereas the other oils/butter are not. In addition, it is important to reduce the amount of sugar you are eating. Not only are high amounts of sugar inflammatory, but since you are working out less, your muscles’ ability to load glucose is reduced, which can lead to elevated blood sugar levels and insulin resistance.
6. Restore Normal Gait Mechanics
Normalizing your gait pattern is incredibly important. If you discontinue your use of crutches too early, you’re setting yourself up for having a limp for a lot longer than if you kept using the crutches. Trust me, I understand the hatred of crutches, especially when all you want is a snack from the kitchen, but that means you have to grab your crutches, crutch to the kitchen, put the crutches down, awkwardly reach for you snack in the pantry, figure out how to transport it without using your hands, grab the crutches again, crutch back to the couch, put the crutches down, and then finally sit down. It sucks, but it’s worth it to keep from developing a limp.
If you’re really lucky (I’m not), your physical therapy clinic might have an anti-gravity treadmill, which is a treadmill that encloses your lower body and then essentially creates a pressurized chamber around your legs that de-weights your lower body. You can de-weight up to 100% of your body weight, and as you are able to walk normally with this decreased body weight, you can begin to decrease the support. These machines are still fairly rare due to their price, but they can work really well for helping you walk normally.
7. Squat Mechanics
It is also important during this phase to begin working on your squat mechanics. In addition to the basics of making it look visually appropriate, you also need to be aware of your weight distribution. It is all but inevitable that when you start doing squats, you will favor your surgical side and place the majority of your weight on the other leg. The best way to fix this is by using a force plate that can measure how much force you are putting through each leg. You will be amazed at how much you favor your injured leg without being aware of it.
Summary
Recovering from surgery isn’t fun, but the strategies I’ve outlined above will keep you moving in the right direction. Improving lower extremity strength, range of motion, and balance are the most important areas during this phase, but taking some extra time to work on things like cardio and squat mechanics will pay off in the long run. In a couple weeks, I will put out another article on phase 3, which is where the real fun begins.
Western Slope Rehab and Performance is Here to Help
If you are struggling with injuries or have recently been in a motor vehicle accident, we can help. We are a physical therapy company that provides home-based orthopedic services in the Grand Junction, CO, area, as well as telehealth appointments throughout Colorado. If you would like to schedule a free consultation, you can call us as 970-462-9177, or fill out our contact form here.
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