by Dr. Andreo Spina
I recently had a doc send me a question regarding squatting and knee injury:
It seems like there are lots of ideas out there about squats but I”m not sure if there’s any “best” or “safest” way to do them. Maybe people with knee pain should find a different exercise to strengthen their quads?
Answer: From observations, I would say that 1% of people in any particular gym actually have the flexibility, coordination, balance, and most importantly KNOWLEDGE to actually perform a proper squat exercise. For these few, the full squat is considered the preferred lower body exercise for safety as well as athletic strength. The squat, when performed correctly, is probably one of the safest exercise for the knees and the best to build knee stability (as well as many, many other befits). The problem of course is when one of the 99% of the ‘others’ attempts to perform it and end up in your clinic. This is not a fault of the exercise…rather a fault of the individuals technique.
Regarding the knees….. A full squat is where the hips drop below level with the top of the patella. Any squat that is not deep, the ‘partial’ squats, stress the knee and the quads without stressing the glutes, the adductors, and the hamstrings. The hamstrings and adductors, when under the tension required for proper form exert a posterior tension on the tibia by way of their distal attachments, and the net effect of the anterior quadriceps tendon insertion is an anterior force against the tibial plateau. With sufficient depth (and with the correct form as described in the video – where hamstring/adductor tension is maintained during the lift), anterior and posterior forces on the knee are balanced. Thus the total shear force on the knee is nil. In partial squats, the anterior shear is allowed to occur without being ‘checked’ by the posterior pull of the hamstrings. It is the shearing forces that cause most of the problems that put the blame on “squats.” As described in the video below, when the knees translate forward, the distal hamstring insertion approximates the proximal insertion thus reducing total tension of the hamstrings and adductors (mainly magnus).