Self-defense is all about stopping power, or stopping an attacker from being dangerous to you. Michael Janich shows you the difference between being effective with a knife and being efficient. Being efficient involves targeting the parts of an attacker’s body that allow him to pose a threat to you. He highlights the primary target areas that you should know about. The first includes the muscles and flexor tendons in the forearm that activate and control the fingers. Damaging these will affect your target’s ability to grip his weapon. Next are the biceps and triceps in the upper arm. If you can eliminate these two muscles, your attacker will not be able to bend and extend his elbow. The last area is the quadriceps muscle in the leg. By slicing this muscle, you take away the leg’s ability to support the body’s weight.