I wouldn't say that it's the body's ability to soften the blow, but instead to handle the strain. What works throughouts a pitcher's body is the velocity in each one of their pitches. Any person can just throw a ball over a plate but it takes a true pitcher to find the mechanics that make them comfortable to throw. No pitcher should ever just throw with their arm but instead be taught or teach themselves how to put their entire body into the throw, starting from the feet, up the legs, through the hips, up the sides, and into the shoulders and arms. Just work on your mechanics and make sure that you aren't throwing with just your arm. When you follow through, help your arm decellerate for less strain by bending your back and having your chest over your stride knee by the time your pivot foot lands on the ground after delivery.