What is knee reaping in BJJ?

Knee reaping occurs when you control your opponent's leg with your legs in a way that puts dangerous twisting pressure on their knee - specifically, when your leg crosses over their thigh while their foot is trapped on the other side of your body. This creates a fulcrum that can damage knee ligaments if they try to escape incorrectly. Knee reaping is banned at lower belt levels in IBJJF because of injury risk. The rule exists because inexperienced grapplers may not recognize the danger and try to explosively escape, injuring themselves. At brown and black belt no-gi, reaping becomes legal because practitioners understand the position and know when to tap. Understanding reaping is essential for leg lock safety.