There are several types of knee strike, such as the knee straight. Catch and neck lock knee strike. Knee strike from the side.
The knee straight don't touch the neck opponent your knees up and push out straight.
Neck lock and knee strike and knee strike from the side the neck opponent lock with arms both 2 side pull opponent in and strike by knee. The goal of knee strike is the torso, abdomen, uppers leg, the opponent gets injured to give up the fight.