The goal of this blog post is to talk about a specific rehabilitative technique that has been proven to reduce re-injury rates and return to sport at the same level of competition, as prior to your injury.
This technique is called perturbation training.
Perturbation training is a technique that teaches you to stabilize your knee by using your muscles. It allows you to form a better connection between your body and brain. The treatment consists of balance exercises in which an external force is added in a specific manner, causing you to isolate and activate the muscles around your knee. The difficulty is gradually increased as you get better to more closely simulate the demands sport may place on your knee.
Pertubation training is effective for people that have had surgery (ACL reconstruction) as well as those who choose to avoid surgery. Click here to read about non-operative management of ACL tears.
The most frequent question I get is “When can I start perturbation/return to sport training?”
I do not use a timeline to answer this question instead I look at certain strength and power criteria:
Full range of motion and has completed “beginning stages of ACL rehabilitation”
Quad strength (Dynamometry) of at least 80%
Single Leg Hop Testing of 90% of greater
Pt has started a jogging progression
Once your leg is strong and power has returned, you can begin sport specific perturbation training. Watch this video below to see how I assess power of your leg with hop testing.
While you may be in a rush to return to sport, you should know that most re-injuries occur in the first year. This is worse if you do not have a strong quadriceps muscle and you show poor lower extremity power as compared to your non-involved leg.
Perturbation training is completed over 10 visits and should take place over a period of time no longer than 5 weeks.
Perturbation training is completed by using a rocker board, a roller board, and a stationary platform to complete a series of 5 different exercises. Each exercise is completed 3 times for 1 minute with a short break in-between.
The first exercise utilizes the rocker board. The rocker board rolls along its semicircular bottom tilting from front to back.
While you are standing on the board, I will be tapping on the front and back. This results in your body responding by turning on the required muscles to stay upright!
Next, we turn the board so that it rocks left and right. This is important because our knee does not just operate in one plane of motion. You need to keep the knee stable in multiple planes to avoid re-injury.
When you get really good at these we can turn the board diagonally to work both planes simultaneously. We can also add distractions such as kicking a soccer ball, throwing a ball, or whatever demands your sport requires.
The next exercise involves standing on a stationary platform as well as a platform that moves!
This exercise is completed with your injured (or healing!) leg on the board that moves. I will then move the board. It is your job to react and oppose the movement. If things are going well there should be little overall movement of the board. As you get better, you will be able to turn on, only the muscles you need, rather than squeezing everything to stop the board from moving.
Just like the rocker board, we start easy with slow predictable movements and as you get better, we make the exercise harder.
We then switch legs, so that your non-injured leg is on the board. You would be surprised how much work the leg on the stationary board actually does!
Finally, you will balance on the roller board, using only your injured leg.
The board will be moved, causing your body to react and stay upright while only using your injured leg. Just like the other exercises we start easy and progress to more difficult movements.
Perturbation training is a pivotal part of safely returning to sport and lowering your risk for re-injuring your knee.
Training is always supplemented with agility and strength training to maximize results.
It has been proven that individuals who combine return to sport perturbation training in addition to normal ACL rehabilitation have better odds of returning to sport at the same level as prior to injury. It also results in lower risk for re-injury!