A ninja has to have an awesome grip, in order to climb ropes, grapple, utilize weapons etc. So here is a great exercise to increase your pinching and gripping strength. Grasp a well-anchored door by the edge. Next lean back into the squatting position, and begin to pull yourself into the standing position. Again be careful when your grip fails you, as you don’t want to be stumbling back into anything that will injure you!