"The influence of cellists' postural movements on their musical expressivity"

Abstract:
The musician's body is often deeply forgotten in the traditional instrumental pedagogy. In the case of bowed-string instrumentalists, the attention is required to be paid on the fingers' dexterity at the left hand or the bow accuracy at the right hand, like preliminary and mandatory conditions for musical expressivity. However, just by observing the play of great violinists or cellists, we can realize that they use postural movements more or less consciously, which are far away from their purely instrumental gestures involved in the sound production. What would be thus the function of these corporeal movements ? If they visually contribute to make a performance more lively, we actually don't know their influence on the perceived expressive acoustical features, such as the musical phrasing or the sound quality.
In my thesis, we try to bring some response elements by investigating the cellists' ancillary movements and their influence on the musical expressivity. On the gesture side, we focus on the chest and head displacements, which are the most salient visually but also the most essential for the cellist's motor planning. On the acoustical side, we focus on the two principal means of producing musical expressivity : the rhythmic and the timbre. This investigation takes place within various areas implying different perspective levels : Instrumental pedagogy, musician's posture, cellist's physiology, and more globally musical embodiment. The influence of postural movements on the musical expressivity is assessed by the means of four postural conditions affecting the cellists' sensorimotor mechanisms : A standard playing condition and three gradual immobilization constraints (mental, physically immobilized by the chest, and finally by the chest and the head). Within each postural session, the bow playing mode (short détaché or large legato) has been chosen as a studying factor of the crossed relationships between sound and motion.
The first part of the thesis highlights the relationships between the cellist's postural movements and their rhythmical expressivity. It appears that the coordination between posture and movement of a cellist is optimal with a good postural-kinetic capacity, which allows to keep the balance by resisting to bow expansions. The natural symbiosis between the musician and his cello also turns out to be a key factor for the metric and rhythmic cohesion between trunk ancillary gestures and instrumental bowing. The rhythmical unbalance caused by the absence of postural movements is particularly repeatable during passages requiring a good motor coordination between the two arms. The discomfort felt is assessed stronger in the bowing mode détaché, which coincides with a bigger uniformity in speed modulations and inter-note timbre colors. The second part of the thesis is dedicated to the detailed exploration of the timbre for a note frequently increased in harshness within the postural constraint by chest and head. This acoustical degradation is generally linked with a weaker bow speed and a narrower gesture of the instrumental right arm. By tracing back to the central body parts, we highlighted the importance of the spine torsion and the right shoulder opening for the sound quality. The whole of these works support flexibility in the postural movement freedom for producing a balanced and expressive play.

Bio:

Graduated from the french engineer school in Electronic and Informatics (EFREI), Jocelyn Rozé worked eight years as a consultant for an information-technology service company (ALTEN). Around the end of this period, he discovered the cello and developed a passion for playing this instrument. Jocelyn then tried to redirect and choose a professional career likely to merge his technical skills to his instrumental passion. He found this opportunity by starting a PhD thesis at the Laboratory of Mechanic and Acoustic (LMA) of Marseille on the topic entitled : « The influence of cellists’ postural movements on their musical expressivity ». He obtained his doctorate degree in 2017 and now he continues a post-doctoral research on the same context to refine and promote his thesis results.