Knee cave is one of the most potentially dangerous technique flaws that can occur during the squat. The anatomical term for knee cave is known as Valgus force or valgus collapse, and occurs when the femur (upper leg) adducts (Moves closer to the centre line of the body) as the tibia (lower leg) remains in the same position or abducts (moves away from the centre line of the body). This can be dangerous because it forces the knee joint into unsafe ranges of motion, placing unwanted stress on ligamentous structures around the patellofemoral joint such as the ACL and MCL.
There are a few anthropometric factors that could pre dispose someone to valgus collapse, however for the purposes of this article, we will only talk about how to resolve this issue if it is caused by imbalance at the hip, which is the cause of the majority of cases of valgus collapse. Valgus knees are often often caused by muscular imbalance around the hip joint, where the adductors become overactive. This inhibits other hip musculature, namely the abductors and the deep hip flexors from properly activating, meaning that the adductors are consistently playing a predominant role in driving the athlete out of the bottom of the squat. This often prevents the knee from tracking directly over the mid foot, and causes the knee to buckle inwards. In addition, limited ankle dorsiflexion can be a determinant of valgus collapse. Tight ankles limit the knee from adequately migrating forward at the bottom of the squat, and as a result the foot compensates by pronating, which forces the knee inwards.
Not only is valgus collapse potentially dangerous, but it also leaves a lifter unable to express all of their muscular force, as key powerful muscles like the glutes are not able to effectively activate to their fullest potential. This bleeds power, and leaves the lifter only able to express a certain percentage of their potential strength. Thus, eliminating valgus stress will not only dramatically reduce injury risk but help to optimise power production in the squat. So how do we solve this problem?
As aforementioned in our previous article, we must first ensure that we put the body in optimal positions to be able to activate relevant musculature – in this case, we must ensure that we develop the motor control to put our pelvis in a neutral position – eliminating any anterior pelvic tilt that can be preventing our deep hip flexors and glutes from properly activating. This begins with a breathing drill. Often athletes are stuck in an extended posture, with the rib cage flared and the pelvis anteriorly tilted. In this position, the anterior core is lengthened, meaning that it can’t contract to draw the ribcage down. This inhibits the diaphragm from being properly used as a muscle of respiration, as it is forced to become a postural muscle. Without restoring an optimal breathing pattern where diaphragmatic breathing is utilised, the pelvis will always resort back into anterior tilt and the glutes and deep hip flexors will not have a chance of activating correctly – Two muscle groups that are essential in correcting knee cave in the squat. Therefore, the first thing we need to do is learn how to properly breathe!
First and foremost we must learn how to draw the ribs down, engage the anterior core and use the diaphragm for respiration. The 90/90 position is a fantastic way of teaching proper breathing mechanics and ribcage control. Assume this position against the wall with a 90 degree angle at the hip and knee. Begin with a full exhale to bring the ribs down whilst simultaneously lifting the hips off the ground slightly (posterior pelvic tilt) to engage the hamstrings. From this position, reach through the ceiling and inhale through the nose, expanding the diaphragm and ribcage 360 degrees. Then exhale fully again, until there is no air left in the body, whilst maintaining this position. Repeat for 2-3 sets of 4-5 breathes.
Side Lying Clam
Now that we have set an optimal breathing pattern, we must now work to activate the relevant musculature that is going to solve our knee cave issue. We will start with the glutes, specifically glute medius, as it is an abductor of the hip (The opposing movement to the cause of knee cave). A side lying position is fantastic for this as it gives a lot of feedback from the floor making it much easier to maintain a neutral lumbar spine and control the pelvis, keeping us out of anterior pelvic tilt.
Setting up in a side lying position and fully exhale to bring the rib cage down. Then take a full inhale, expanding the diaphragm and ribcage. From here, raise the top knee, initiating the movement from the lateral hip. It is essential that we keep our top foot firmly planted against the wall, maintaining three points of contact at all times– big toe, little toe and heel. Keeping the hip in abduction, take 8-10 full breathes with the same breathing pattern as the 90/90 exercise. Ensure that all movement comes from the hip, and there isn’t any pelvic/spinal rotation involved in the movement. You should feel the side of your hip start to burn.
Supine Psoas March
Now that we have some glute activation, we need activation in other musculature around the hip to promote muscular balance and to keep the knee tracking optimally over the mid foot as we descend into the squat. The deep hip flexors (iliacus/psoas major) will further help to offset the valgus collapse of the knee. Lie in a supine position with a your knees raised, and your hip flexed past 90 degrees, with a light resistance band hooked around your feet. Fully exhale to draw the ribcage down. Keeping one leg flexed, extend one leg until it is straight, ensuring that the abs stay tight and the lower back stays fixed against the ground. Repeat one leg at a time.
The psoas march is a fantastic exercise because it not only activates the hip flexors on one side, but at the same time the opposite hip flexor is fighting to resist extension of the lumbar spine. This is an essential skill to develop as it prevents the pelvis being pulled into anterior tilt. To make the most of this exercise it is crucial that the ribcage stays down and the anterior core stays tight.
Ankle Mobility drill
As mentioned earlier, limitations in dorsi flexion can make the risk of valgus collapse increase, as the foot pronates to compensate and to provide more anterior knee migration. Therefore, stretching the plantar flexors of the ankle can help to resolve the issue.
Place one foot on a box at approximately knee level, ensuring to maintain a neutral spine (No excessive rounding or arching of the lower back). Exhale fully to draw the ribcage down, and then push the knee into dorsi flexion, using your body weight to leverage forward. Oscillate forwards and backwards, left and right, finding areas of the joint that feel particularly tight and restricted. Ensure that 3 points of contact are maintained on the box with the foot – big toe, little toe and heel. Adding a band to this stretch can also be helpful, as shown below. Perform for a minimum of 20-30 seconds.
Putting it all together – Integration
Now that we have set a correct breathing pattern, activated relevant musculature and stretched tight muscle to resolve knee cave in the squat, there is only one thing left to do…squat! However, if we go ahead and throw a barbell on our back and start slapping on the plates, we are bound to start falling back into our knee collapsing habits if we haven’t had any practice at teaching our neuromuscular system to maintain position and activate the relevant muscles in an actual squatting movement pattern. Enter the Goblet Squat.
Goblet Squat with band around knees
The goblet squat is a brilliant exercise for learning the squatting pattern, as you can work on ribcage/lumbo-pelvic control, and cues/mechanics before progressing to loading the spine with a barbell. The addition of the band is a reactive neuromuscular training (RNT) technique that forces optimal knee tracking mechanics whilst performing the squat. By feeding the dysfunction by providing external valgus stress in the form of the band, the lifter is forced to fight against this, making it a fantastic learning tool for preventing knee cave.
Hold a kettle bell 6-8 inches from the torso with a light resistance band around the knees. Exhale fully to draw the rib cage down and squeeze the glutes to remove anterior pelvic tilt of the pelvis. Slowly descend into the squat, keeping an upright torso and ensuring the knees are tracking directly over the mid foot, resisting the inward pull of the band. Ascend and squeeze the glutes at lockout, ensuring full hip extension is achieved.