4 The Playing Mechanism
Though the fingers touch the keys, they are not the only body part contributing to piano technique. When seated at the optimal height and distance from the keys, the hand, wrist, and forearm can work together as one unit, facilitating greater power with less effort.
To experience how the forearm-wrist-hand unit works, think of your forearm as a drawbridge with the elbow as the fulcrum. Raise your hand by bending at the elbow, rather than the wrist. Now release the weight of your arm and notice how heavily it drops. This weight can be released into the keys to produce sound.