For pierrot ensemble
Music and movement have been bound together seemingly since their inception. There is no dance without some kind of rhythm or beat, people in every concert audience are likely to tap their toe or bob their head to compositions that explore groove, and musicianship itself has its own kinesthetic capacity and requirements. The musicians that seem to most worry about movement as it relates to music, however, are the conductors. Slight variations in their choreography and/or improvised gestures can result in drastic changes in the way an ensemble performs a note, a phrase, or a piece.
The bread-and-butter reference for conductors with regard to movement and how to classify it has to be the the Eight Laban Efforts. Rudolf Laban (1878-1958) was a movement theorist, a choreographer, and a dancer who said that all of human movement could be boiled down to the component parts of direction (either direct or indirect), weight (heavy or light), speed (quick or sustained), and flow (bound or free). These components, when combined, create the eight efforts: Wring, Press, Flick, Dab, Glide, Float, Punch, and Slash.
As a motion, wringing is indirect, heavy, sustained, and bound. Conductors tend to use the motion in slower excerpts at moments that are more harmonically crunchy than the surrounding material, but this is by no means a set rule. In fewer words, to wring means to twist something forcefully. When somebody wrings something, they seek to use the motion to force something out of the the object they are wringing, like water out of a cloth or life out of a chicken.
WRING aims to have the musicians convert this kinesthetic action into a musical one without the aid of a conductor. Notes are to be twisted with such force that they undergo sonic change. Wide vibrato (up to a half step in either direction) and glissandi are the principal methods for this, but the harmonic series is to be wrung out of singular pitches by the piano, flute, and strings, with each instrument taking a different approach to this action. Further, rhythm is wrung out of harmonics in a more gentle way through use of the Seagull Effect (pioneered by George Crumb), and different overtones and textures are to be wrung out of notes through the use of ponticello bowing and growling in the clarinet.