Decade of thai boxing + kickboxing competing and training with some of the best amateurs in the US. Knee stomps are one thing, shin to the outside of the knee joint is another. You can dislocate or snap a ligament with inside or outside low kick if you land on the knee joint.
Re back of the head, it’s more like where the skull starts and neck ends that’s the problem spot. That’s where you aim with a high kick exactly because it’s an off-switch.
