What is a heel hook?

A heel hook grips the heel and rotates it to attack the knee ligaments - one of the most dangerous submissions in grappling. Inside heel hooks rotate the heel toward the inside of the body, stressing the ACL. Outside heel hooks rotate outward. Heel hooks can cause serious knee injuries before you feel significant pain, so you must tap early and apply them slowly in training. They are restricted at lower belt levels in most competitions but are essential knowledge for advanced no-gi grappling.