Why do my knees cave in when I squat?
Nowadays, almost every coach teaches the squat, or how to correct the squat, starting at the wrong point in the kinetic chain. Most coaches will cue on how to position the back and core, engage the hips and abduct the knees all a while ignoring what is going on at the ankle as the trainee is wearing thick immobile lifting shoes. With the platform in lifting shoes being helpful in decreasing the amount of dorsiflexion required to maintain balance, often it isn’t enough to prevent the foot from falling into a pronation pattern during the lift itself.
The place my eyes go to first when trying to adjust someone’s squat is the ankle joint. Assuring that ankle mobility is proficient primarily into dorsiflexion, secondary movement from pronation to supination is necessary to get the segmental muscle firing needed to perform the lift. Chiefly due to the lack of dorsiflexion, most individuals are not able to get their ankle to supinate sufficiently when squatting which may lead to the cascade of events that follow.
In the case of not being able to hold a supinated foot, the Navicular bone of the foot starts to drift medially having the Talus bone, which is the primary bone responsible for transmission of body weight to the foot, follow. With the Navicular and Talus drifting medially, the Tibia and Fibula, which are the bones of the lower leg, will internally rotate and collapse inwards. With the Tibia and Fibula following the foots projected pathway, the knee joint and the femur have no choice but to follow as the entire base of support in the lower leg is caving inwards. This condition of having the knee drive inward under loaded hip flexion is called knee valgus. In many cases, if continuously repeated, impingement symptoms at the hip may occur. This phenomenon takes place as the length tension relationship between muscles responsible for adduction (bringing the leg inwards) and abduction (bringing the leg outwards) is compromised and pinching structures deep in the medial hip.
Those who suffer from flat feet will have the hardest time squatting as the valgus effect will be most prominent. If this is the case, start off by correcting any limitations in ability to go into dorsiflexion at the ankle. The most common method to address this mobility dysfunction is with the help of Self Myofascial Release (SMR), also known as foam rolling. Once the tissues allowing for dorsiflexion loosen up, one must follow up with corrective exercise strategies to mobilize the ankle and stabilize it under load. Weighted ankle dorsiflexions without foot collapse and cueing a short foot (or supination) exercises are great to begin loading the ankle. The final stages of ankle rehabilitation will come in the form of balancing drills that force the individual to keep this short foot all a while completing a task that involves movement of other structures in the body.
Once the ankle has been addressed, the hip musculature must be trained next. The use of Reactive Neuromuscular Training (RNT) is very efficient technique to teach the individual how to create changes in muscle activity using external cues. RNT is defined as the training of the muscle and nervous system while reacting to an external stimulus. In the case of an inward knee drive when squatting, placing a band around the knee and having tension pull it into more valgus will invoke a response in the individual to pull the knee outwards. With the knee wanting to move inwards, this external stimulus created by the band will force the central Nervous System to engage the muscles responsible to pull the knee outwards and allow for better joint centration. Through constant repetition using this external stimulus, the individual will learn how to engage these muscles and create better biomechanical efficiency.
No individual is the same, and frequently this process must be adjusted to accommodate everyone’s needs. The overall principles stay the same, just how to apply the concepts changes. So next time you squat, look in the mirror and see if your ankle and knee stay aligned as if they don’t, you could be lifting more given your ankle movement is improved.