When instruments are near at hand, movements need only moderate joint displacements and muscular activity is low.

The classification of these movements into different categories, drawn up by industry and not by ergonomics, is complete nonesense ! We must not do away with any of the articular movements as recommended by this classification. All movements, as long as their displacements are moderate, help to maintain a healthy muscular and articular physiology. In fact, we must avoid staying static !