Kinetic Hygiene: Knee Stability Summary

Author: Dr. Zak Gabor

This week we dove into discussion of the knee joint, and why is desires STABILITY. Let’s revisit some of the points and concepts discussed, a go a little bit deeper.

It started with understanding a very important concept

EACH joint has ratios of inherent bony stability to soft tissue stability (or dynamic stability). Generally speaking, joints that have more bony stability crave mobility, and vis versa. So let’s take a look at the knee:

Image 1

Essentially two relatively flat bones sitting atop each other. When you consider the extreme example of boney stability like the ball and socket of the hip (fun fact: 70% of femoral head contacts the hip joint), you can appreciate the decreased boney stability of the knee, THEREFORE, the knee depends on soft tissues and contractile structures (ie muscles) for STABILITY. While inherently BONEY joints with great stability crave mobility.

Something that always resonated with me was when I heard Charlie Weingroff talk about how “the knee is dumb.” What does that mean?

It means that in closed chain, we really cannot move the knee independently with out moving the hip and/or ankle. Whats that mean? Hip and ankle have HUGE implications on knee control (aka stability).

Putting it all together:

What makes most sense than, for a awesome daily exercise for knee stability? Something that combines hip/ ankle activation, as well as isometric contraction of muscles surrounding the knees (ie quads, hammies, adductors, calfs).

How about this classic:

SINGLE LEG STANCE IN SLIGHT HIP HINGE.

You can challenge your self by closing your eyes, or standing on an uneven surface. BUT, we spend roughly 60% of our gait cycle on one leg, so it would make sense to have good single leg control, right?

 

Try dosing this for 10-30 seconds once a day and go from there. Stable knees are healthy knees! See post below for example of what we want, and what we do not want.

Kinetic Hygiene: Knee Stability ( WHY and HOW ) ________________________________________________________ 🤔CONCEPT ALERT🤔: . I want you all to understand a very important concept. EACH joint has ratios of inherent BONY stability to SOFT TISSUE stability (static/dynamic stability). This concept will lay a framework for following posts in this series. ••• Lets apply this for the knee: essentially two relatively flat bones sitting atop each other. When you consider the extreme example of bony stability like the ball and socket of the hip (🤓nerd fact: 70% of femoral head contacts the hip joint), you can appreciate the decreased BONY stability of the knee. THEREFORE, the knee depends on soft tissues and contractile structures (AKA MUSCLES) for STABILITY. While inherently BONY joints with great stability crave mobility. ••• Something that always resonated with me was when I heard Charlie Weingroff talk about how “the knee is dumb.” What does that mean? 🤷🏻‍♂️ . It means that in closed chain, we really cannot move the knee independently with out moving the hip and/or ankle. Sooooo…Hip and ankle have HUGE implications on knee control (aka stability). ••• Let’s put it all together: . What makes most sense than, for a awesome daily exercise for knee stability? How about something that combines hip/ ankle/foot activation, as well as isometric contraction of muscles surrounding the knees (ie quads, hammies, adductors, calfs). How do we get that done? KEEP IT SIMPLE. How about this classic: . SINGLE LEG STANCE IN SLIGHT HIP HINGE. 1️⃣Hip external rotators on 2️⃣Isometric contraction of knee muscles via "soft knee" cue 3️⃣Ankle stability and "short foot" on ••• You can challenge yourself by closing your eyes, or standing on an uneven surface. BUT just another point: we spend roughly 60% of our gait cycle on one leg, so it would make sense to have good single leg control, right? Try dosing this for 10-30 seconds once a day and go from there. Stable knees are healthy knees! @strong_by_science ________________________________________________________ #simplestrengthphysio #physicaltherapy #PT #DPT #DPTstudent #physio #fitness #workout #health #training #exercise

A post shared by Dr. Zak Gabor — DPT, CSCS (@simplestrengthphysio) on

 

If we continue on this notion of gaining knee stability through muscle activation. Let’s look at Teddy’s post on dynamic knee stability when it comes to reducing risk for ACL injury.

 

As we learned from this post, the ACL is most vulnerable during the first 20 degrees of knee flexion in closed chain (roughly). This is because as we get closer towards 20 degrees of flexion, it puts the knee in a “loose pack” position, thus allowing for tibial rotation which we know contributes to the holy grail of ACL injury mechanisms.

Image 2

This means that we want to OWN knee dynamic stability throughout this range of 0-25 degrees in concentric, isometric, and eccentric fashion.

 

 

Teddy does a great job of demonstrating three exerises that target deceleration (or eccentric) training of the knee musculature to help better absorb force and control knee mechanics against mechanisms associated with ACL injury.

 

 

 

Dynamic Knee Stability❗️ ——- In this last post of #KineticHygiene week 2 we talk stability and ACL's. This injury typically happens at about 22 degrees of knee flexion. At this angle the ACL is still taut enough to be subjected to forces and rupture, yet the knee is loose packed enough to allow tibial rotation. This makes the 0-25 degree knee deceleration mechanics extremely important. The goal of ACL rehab/prehab is to create stability at this slightly bent knee position. ▪️▪️▪️▪️ Video 1️⃣ shows your basic 3 cone drill. This is essentially mini squats with the opposite leg driving in different directions. The leg drive changes the demands on the stabilizing hip, knee, and foot. This drill can also be used diagnostically, as in the Y Balance test. ▪️▪️▪️▪️ Video 2️⃣ shows a sagittal plane depth drop. The goal here is a strong "stick" landing where the knee does not go into more than 25 degrees of flexion. Landing in a deeper flexed position is much less relevant to ACL consideration and does not help retrain protective stability. . ▪️▪️▪️▪️ Video 3️⃣ shows a frontal plane to sagittal plane jump. The initial lateral hop followed by a change of direction reproduces one of the most provocative movements and methods of injury for ACL's. The non-contact ACL injury is characterized by poor plantarflexion deceleration, poor ankle/hip/knee sequencing, and a rapid sport demand for changing direction. This drill addresses 2 of these factors, as the quick change of direction demand can only be recreated in a reactive agility or team sport environment. . ▪️▪️▪️▪️ These drills should play a significant role in dynamic knee stability for athletes and they each represent a distinct time period of progression during a rehab effort. ▪️▪️▪️▪️ #KineticHygiene week 3 is up next! 👉🏼@joegambinodpt 👉🏼@simplestrengthphysio . . . . . . #biomechanics #painscience #evidencebasedpractice #evidencebasedmedicine #backpain #shoulderpain #trapbar #abcheck #6pack #shoulder #strengthandconditioning #powerlifting #usapl #deadlift #dpt #dptstudent #physio #powerclean #crossfit #physiotherapy #fitfam #physicaltherapy #clinicalathlete #fitness #kneesurgery #windlass #footpain #hippain

A post shared by Dr. Teddy Willsey DPT, CSCS (@strengthcoachtherapy) on

 

On the contrary, Joe was able to play devils advocate, and give us some excellent food for though on why we also might want to take a look at expressing tibial rotation. Let’s first understand the closed chain “Screw Home” Mechanism. It starts by understanding the anatomy of the Popliteus muscle. The Popliteus, as shown below, has origin on the lateral femoral condyle, and runs into the tibia obliquely directly above the SOLEAL LINE, and important landmark on the back of the Tibia. So we can see how in open chain, the Popliteus will rotate the Tibia internally relative to the Femur. On the other hand, in closed chain, the Popliteus will rotate the the Femur externally relative to the Tibia, “screwing it home” and locking the knee joint.

Image 3

Regardless, we understand that the knee joint HAS to be able to express some rotational ability, and Joe hits the nail right on the head with this exercise.

 

Joe also notes that a lot of his patients will often lack Tibial internal rotation, so this drill can be excellent for establishing baseline Tibial IR. See drill below!

Kinetic Hygiene – Knee Mobility __________________________________ Yes, it is true that based on the joint by joint model we have been referring to, the knee is a stable joint. . But just because it's main function is stability, doesn't discount the importance of knee mobility. ••• We all know the knee must extend and flex, yet we often over look the minute, yet important motion that is tibial external and internal rotation. . Even though we don't typically see this motion happen, it is extremely important for function – particularly the screw home mechanism – which refers to the tibial rotation that occurs with locking and unlocking the knee. ••• Lack of tibial rotation, especially IR is common in many patients I see with knee pain and occurs in 100% of post op patients. . Tibial Rotation with Foam Roller 1️⃣Place a foam roller between your knees. This will ensure you are not moving the femur during this movement. 2️⃣Keep your feet flat on the ground and try and rotate your lower leg as far as you can without compensating. 3️⃣Rotate your lower leg all the way inward, past neutral (again, without compensating). 4️⃣Repeat. 5️⃣Keep in mind, the intent should be from the knee, not the foot. . Questions, comments, concerns? Let's here em' 👇. . Stay tuned for some more kinetic hygiene 💣's from @simplestrengthphysio and @strengthcoachtherapy @kinstretch @drandreospina @drmchivers @perform_better

A post shared by Joe Gambino, PT, DPT, CSCS (@joegambinodpt) on

 

CONCLUSION

So what are the key takeaways?

-Knees are a very vulnerable joint in terms of lacking bony stability, therefore we need to train dynamic stability!

-We know that knees are especially vulnerable at 0-20 degrees of flexion, so training our muscles in that range can have huge implications on reducing potential risk of ACL injuries!

-Knees must be able to express rotation in order to properly screw home and lock for gait and running, when we don’t have that ability, we might run into potential issues and knee pain secondarily.

 

Image Links

  1. http://www.precisionnutrition.com/all-about-the-knee
  2. http://strengthcoachconcepts.com/articles/Single+Leg+Movement+and+The+Lateral+Sub-System/
  3. http://corewalking.com/knee-stuff-popliteus-muscle/

 

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