Reaction Force
By Newton's Law, every force has an equal and opposite force. An automobile that crashes into a wall will deliver a force of 2000 pounds, and in return, the wall will deliver a force of 2000 pounds onto the car. By understanding reaction force, a student will be able to acquire an impressive amount of power with very little strength due to the combination of forces. An example of this in Taekwon-Do is pulling your left arm backwards while executing a punch with the right hand.