"Hammered; a sharply accentuated, staccato bowing."
As a young student I learned from a teacher who dictated a wide use of martelé, including in Baroque and classical repertoire. Later I was influenced by Baroque performance practice and relegated martelé to a practice tool and avoided its use in repertoire. Bowing fashions can change, and while today martelé is rarely heard in Baroque it is now often used instead of spiccato in the early Romantics (especially in Rode, Viotti and Kreutzer).
Martelé has always survived as an excellent practice tool and a way to develop 'bowing health'. It is an excellent trainer for:
Developing good control over the contacting and releasing of the string.
Developing clarity in any string crossing passage (see Martelé as a Useful Practice Technique).
Practising the point of contact for upper half strokes with fast bow speed.
Developing the 'in and out' action of the upper arm in the upper half of the bow, especially to get the upper arm to fall back early enough in the up-bow stroke.
As a practice technique, try dropping the right elbow on the up-bow to encourage the release of the upper arm.
Martelé has a speed limit. Beyond a metronome marking of about 80 (four notes to the beat) we need to use a reflex (rebound) stroke, such as sautillé or up-bow staccato. In his book Principles of Violin Playing and Teaching, p.72, Galamian notes that you can extend the speed of martelé at the tip by turning the bow stick towards the bridge. (Tremolo uses a similar angle of the bow stick to achieve speed with minimum effort).
Martelé often begins with a collé impulse (see Collé in Other Bowings). In this way martelé can be seen as an extension of collé.
Martelé is useful in developing the in and out action of the upper arm in the upper half of the bow. We often do not allow the upper arm to fall back early enough in the up-bow, and observing our martelé in the mirror will highlight this.
Resources - Bibliography
Definitions reprinted with permission from American String Teachers Association.