Touched on this earlier and going to be a big part of our spring.
As for the first saying regarding getting your elbow up, this might be one of the most common phrases I heard throughout little league, because it was thought that if your elbow was below your shoulder you were vulnerable to injury. The opposite actually turns out to be true. In reality, your elbow SHOULD be slightly below your shoulder at foot strike. For those of you doubting this proposition, I encourage you to put your arm up beside your body in a 90 degree angle and move it up and down until you find the spot that feels most comfortable for your shoulder. As you move your arm up with the elbow rising above the shoulder you can feel the tightness and uncomfortableness as the shoulder muscles are impinged into that range of motion. Similarly, as your elbow is moved too far below the shoulder the same type of uncomfortableness is felt. For most people, if they were told to stop at the position that felt the best on the shoulder their elbow would be just slightly below the shoulder (or perhaps parallel). This is due to the fact that this position is the most natural on your arm and causes the least amount of stress – which is what we are looking for.