How many times have you heard someone utter the saying, “I have bad knees?” And, how many times is this phrase used as an excuse for not committing to a training program or participating in an activity? Aside from low back pain, knee related problems are rampant amongst professional and recreational athletes that prevent them from playing their sport or enjoying their movement practice. What is going on here?
Knee pain is a mystery for most people, and the joint itself is often regarded as the prime suspect and scapegoat for the rest of the lower body. It is likely to be blamed for everything, including injuries and pain, but is never really the source of the problem.
You Compensating Son of a…
Your body in motion is a map. If you don’t have access to all the areas on that map, your brain is very good at finding detours. These detours are your compensation patterns. And, these compensation patterns are how you move through life. Anatomically, the way the knee is structured, makes it susceptible to pain and injury because it doesn’t compensate well. The knee doesn’t have very many bypasses or roundabout options to take. Biomechanically, the knee is controlled by how well your foot and hip function.
Once the foot hits the ground, everything changes. Closed chain interaction with the ground starts with our feet, and is needed to ensure optimal movement through the ankles as it communicates up the chain to the hip. Guess what sits in the middle of this pathway? The knee. When there is a communication breakdown at the foot, hip, and trunk, this impacts energy transmission and dissipation, along with attenuation of forces through the knee joint.
Where this force bleed occurs will dictate which soft tissues in and around the knee joint are affected, leading to many of the common pathologies we see today in athletes, including ACL tears, meniscus damage, patellar tendinitis, and hamstring tendon strains.
No matter what issue is occurring at the knee, there are a few key concepts we need to understand about how the knee functions if we want to help keep our knees healthy and strong.
You Call That Flexing, Bro?
There is a difference between your knee bending and your knee flexing in the sagittal plane. The former is simply taking your heel to your butt or attempting to straighten your knee. The latter includes rotation at the lower leg (tibia) and a counter rotation of the thigh (femur). This is called the “screw home mechanism” of the knee and is characterized by roughly 30 degrees of internal rotation (tibia) as the knee bends and 30 degrees of external rotation (tibia) as the knee extends. Note that the femur is rotating in the opposite direction as the tibia during these patterns.
This spiraling motion, or wringing out of a towel, is vital to attenuating forces as they pass through the knee joint. And, the only way to generate this torque creation is through correct activation of the foot. A problem arises when athletes lack awareness and intention behind their movement. First, we need to be aware that this motion is occurring. Second. we need to be intentional with our movement rather than haphazardly slapping 405# on your back and taking it for a ride.
Here’s what typically occurs: Most athletes are cued to drive the knees out, which creates supination at the foot and more internal rotation of the tibia, leading to abduction and external rotation of the hip. This lengthens the glute, but ONLY in the sagittal plane. We have left out the other two planes of motion! We now only have one strategy to utilize during our squat, meaning we have neglected rotation, which would have allowed for forces to be distributed through other parts of the body. Sure you can get away with this for a while, until you hit a plateau or experience pain.
There is actually a chain of spiraling pathways that need to occur during the squat. As you lower down we should see pronation at the foot (with pressure over the big toe), which allows the tibia to externally rotate and femur to internally rotate, putting the glutes on an active “stretch” in the bottom position, and placing them in the best position to optimally contract when standing up. Starting at the foot, we get a supination motion (lifting of the arch) which allows the tibia to internally rotate and femur to externally rotate (function of the glutes) to unleash the power stored in your hip drive to explode and push that bar through the roof.
The Spiral Pathway to Power
Sure, the tissues around your knee have capacity to handle a high amount of stress…until they don’t anymore. They have a tolerance set point for load, and once that threshold is crossed, signals from the brain will alert you in the form of pain. This is also where we run into problems of achy joints and repetitive wear and tear leading to accelerated tissue damage in structures like the meniscus, which are designed to be the shock absorbers of the knee.
Similar mechanics are needed for movements like sprinting. As you control yourself falling forward, the foot goes from a pronated position to absorb the load of your body against gravity and must re-supinate to create a rigid lever from which to push off. This supination is coupled with external rotation of the tibia and subsequent internal rotation and extension from the femur and hip to propel your body forward. If any of these joint motions are not fully accessible, it could potentially lead to excessive motion at the other joints, increasing mechanical stress and creating symptoms. In order to fully understand and resolve our knee symptoms, we need to make sure that each of these force-coupled movements at the foot, knee, and hip are integrated well.
Absorb and Explode
When we’re discussing movement, our conversations are usually focused on biomechanics and how the nervous system responds and is impacted by our movement choices. What we should also be considering is the role the knee plays in shock absorption and transfer of kinetic energy from ground reaction forces generated by the foot.
An often-overlooked structure of the human body is the fascial system. In particular, at the knee, the deep longitudinal fascial subsystem running through the tibiofibular joint (made up of your lower leg bone – the tibia and fibula) is vitally important for assisting with additional stability for activities like running and jumping that require a lot of impact force to be transmitted through multiple joints in a movement pattern sequence.
When walking, our heel must first strike the ground, transferring energy through the heel, then the ankle, then the fibula and knee joint, through the hamstrings, and finally up into the pelvis. If we lack rotational capacity, or are stuck in one compensatory movement pattern, we lose our ability to respond to load by transmitting some of that force into the fascial system within the tibio-fibular joint, increasing our chances to experience knee symptoms due to perpetually overloaded soft tissue structures like the lateral hamstring or IT band, which could potentially alter mechanics upstream at the hip or downstream at the ankle as your brain tries to offload the already compromised tissues.
Master Your Movement: Solve the Mystery
The knee, often viewed as a simple joint, is really more complex and important for athleticism than most of us give it credit for. Knee pain and injury are incredibly common, and as coaches we need to have better ways of understanding, assessing movement, and coaching through compensations in the lower body that increase the likelihood of knee pain or injury.
Tell the big brother of the hip and little sister of the foot and ankle to get their shit together and start being team players. Make sure that you are looking at the knee through several different lenses. Take a step back and assess movement from a more global perspective.Understand there are more functions in the knee than just flexion and extension, and that isolated hot spots at the knee are a signal for a more integrated approach to movement assessment and programming.
Take your knowledge of knee and coaching to the next level with our in-depth online ACL Injury Prevention course designed to enhance your ability to see movement and provide specific training strategies to correct poor movement specific to each of your athletes.
If you are interested in a review of your movement and remote consultation with Dr. Matt Zanis, email firstname.lastname@example.org for scheduling and remote coaching information.
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PT, DPT, FAAOMPT, OCS, ATC, CSCS Former baseball catcher and an avid outdoorsman. Worked with Division 1 basketball, football, and track and field at the University of Pittsburgh, along with the Pittsburgh Pirates and Arizona Cardinals organizations. Received a Bachelors in Athletic Training from the University of Pittsburgh in 2011 and a Doctorate in Physical Therapy from Duke University in 2014. Is board certified in Orthopedics and a Fellow through the American Academy of Orthopedic Manual Physical Therapists. Is a PT with the United States Olympic Committee and USA Shooting. Currently operates his performance therapy practice in Scottsdale, AZ with Dr. Tom Incledon of Causenta Wellness, and became a Power Athlete Block One Coach in September of 2017.
Dr. Zanis utilizes the Power Athlete Methodology to optimize performance, reduce injury risk, and rehab his clients and athletes through movement assessment, coaching, and individualized program design.
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