There is controversy as to how deep you should sink your hips while performing a squat. Now I had always adopted the 90 degree rule (if you don't know the 90 degree rule, it is not allowing your knees to bend below 90 degrees when performing the squat), but after realizing how irrational that was, I had to change the way I coached.

Now I understand that are extenuating circumstances that prevent some from squatting below 90 degrees in a squat such as injury. However in a healthy individual there is no reason why you can't squat as deep as your body will allow you. Think of how often you squat during the course of a day. Do you actually pay attention to how low you go? Often we don't squat below 90 degrees because our muscles are so tight that we don't have the mobility to get below 90 degrees. But the truth is, when our hips and leg muscles are mobile and have the flexibility, our squat range of motion becomes much larger and allows us to move over the full range of motion the body intended. The horror stories you hear about knee injuries from squatting are almost always from those who didn't use the correct technique and/or had a major limitation in their range of motion causing them to compensate in a negative pattern.

Lower body alignment is very important when squatting, even more so when squatting below 90 degrees. What I mean by alignment is that the thigh, knee, lower leg, ankle and foot all must line up with each other in a straight line while performing a squat. Often I'll see a deep squat with the knee caved in or the ankle caved inward. That is not good alignment, and that is when injuries happen. The best way to know is to watch yourself in the mirror while performing the squat and see if you have any joints that cave inward. Then work on your flexibility of your hips and leg muscles to improve upon your alignment and ensure maximum benefit from one of the best exercises for weight loss.

We don't stop at 90 degrees when bending our elbow, then why would we do it at the knee? The knee and elbow are the same type of joint and both have more complicated joints above and below them which is the true source of a problem. Sure if you have an injury or condition in your knee, stopping at 90 would be beneficial, but if you don't, work on your mobility and flexibility of your hips and lower leg, and make sure your legs are in alignment and prevent caving of your legs inward.