Joint lock

Imagine your arm is like a toy robot arm. There are lots of little parts that make it move, like the elbow and the wrist. When someone puts a joint lock on you, they twist or push or pull your arm in a way that makes those little parts get stuck and stop moving. It can hurt a lot! But it's important to know how to do it and how to get out of it so you can keep yourself safe if someone tries it on you.