The first principle is to sit at the correct height and insist to students (or their parents) that the bench at home be at the correct height. Some piano methods do say things like "the forearm should be level when the student sits erect without hunching the shoulders," which is correct; much the same advice is found in any ergonomics text. If a person is not at the correct height, the body is likely to compensate somewhere. A person sitting too low may hunch the shoulders or lift the elbows, a person sitting too high may drop the wrist or pull the shoulders down. All of these compensations involve static muscular activity that limits freedom and can in time lead to injury.

Since the correct bench height is the one that puts the forearm level, it is not the same for everyone, and it may not be the same even for people of the same stature. The correct bench height is determined by the relation between the length of the upper arm and the length of the torso, and this proportion varies from one person to another. A handy way to find the correct height is to sit upright with the arms hanging freely and the fingertips resting on the keys. Then adjust the height of the bench so as to place the tip of the elbow even with the top of the white keys. To many pianists, the correct height will feel high at first, since most benches are too low for most people. Even adjustable benches do not go high enough for many people.