(21) Forearm Rotation

One of the most important piano playing motions is forearm rotation (FR), one of the fastest motions of the hand. It is the main motion used to play the thumb and pinky. The two bones in the forearm are the ulna and radius (see Mark P. 82). In FR, the larger radius, connected to the thumb, is rotated around the thinner ulna, connected to the pinky. FR is used in fast parallel sets, tremolos, Albertis, scales, arpeggios, etc. In the FR motion, the thumb is rigidly attached to the hand, which is moved by FR. A small thumb movement can be combined with FR because, although the thumb muscles are slower, smaller movements are faster. All established schools of piano, such as the Alexander technique, teach FR. The wrist and arm motions evolved to be the fastest motions because their speed is needed for tree climbing, fighting/defense and throwing/catching objects. FR is fast and is needed in most fast passages; thus, when practicing fast passages, always check to see if FR might help.

Practice FR by contrasting it with quiet hands, as Bach did with his Inventions #8; – where you need both FR and quiet hands and can therefore demonstrate the differences between them. It is a mistake to think that, at sufficient speeds, you must always play with quiet hands. Other examples where FR is needed are the tremolos and Alberti motions in (57) Beethoven's Pathetique, Op. 13, First Movement. Many students struggle with speed in these passages, often developing stress and even suffering injuries because they were never taught to incorporate FR. With FR, speed, power, and endurance cease to be problems, allowing play with relaxation.