Self-Defense Sambo - Leg Sweep
Human Weapon video tutorial: Leg Sweep or leg trip refers to a technique in which the combatant performing the leg trip uses his or her own leg(s) to off-balance an opponent, hence causing the opponent to fall to the ground.

Self-Defense - Muay Thai - Flying Knee
Human Weapon: This video tutorial shows you how to do a Muay Thai Technique. A flying knee (known as hanuman thayarn in Muay Thai, and sometimes called a jumping knee) is a knee strike very similar to a front knee, except that it is performed in stand-up fighting by jumping, and often by rushing towards the opponent.

Self-Defense - Pankration - Achilles Leg Lock
Human weapon: This video tutorial shows you how to do an Achilles Leg Lock, from Pankration. An achilles lock (also called an achilles hold or achilles squeeze) is a compression lock that involves pressing the achilles tendon into the back of the ankle or lower leg.