According to WebMD, the knees may hurt when squatting for a number of reasons including, but not limited to, performing the exercise incorrectly, tearing the anterior cruciate ligament or tendons in or around the knee, being overweight, doing too many squats at once, and working out only one or two muscles while ignoring the others supporting the knee. Anyone experiencing significant pain in the knee should seek medical help.
Tearing or straining the anterior cruciate ligament, or ACL, can result in serious injury and cause significant knee pain. Torn or strained ACLs are at the heart of approximately 150,000 injuries in the United States each year, according to Web MD. If a person is involved in a sport with jumping and twisting, the ACL could be the culprit of pain during squats.
Exercising incorrectly can cause pain in the knees, especially if the squats are repeatedly done incorrectly. Anyone trying a new exercise should seek help to make sure he is performing it correctly in order to avoid injury. Being overweight while performing squats also places strain on the knees, causing pain and potential injury. Anyone performing squats must also remember to exercise all the muscle groups that support the knee and not just the quadriceps muscles of the thighs.