Coordination of bowing and fingering in violin playing

Playing string instruments implies motor skills including asymmetrical interlimb coordination. How special is musical skill as compared to other bimanually coordinated, non-musical skillful performances? We succeeded for the first time to measure quantitatively bimanual coordination in violinists playing repeatedly a simple tone sequence. A motion analysis system was used to record finger and bow trajectories for assessing the temporal structure of finger-press, finger-lift (left hand), and bow stroke reversals (right arm). The main results were: (1) fingering consisted of serial and parallel (anticipatory) mechanisms; (2) synchronization between finger and bow actions varied from −12 ms to 60 ms, but these ‘errors’ were not perceived. The results suggest that (1) bow-finger synchronization varied by about 50 ms from perfect simultaneity, but without impairing auditory perception; (2) the temporal structure depends on a number of combinatorial mechanisms of bowing and fingering. These basic mechanisms were observed in all players, including all amateurs. The successful biomechanical measures of fingering and bowing open a vast practical field of assessing motor skills. Thus, objective assessment of larger groups of string players with varying musical proficiency, or of professional string players developing movement disorders, may be helpful in music education

Bimanual Coordination of Bowing and Fingering in Violinists—Effects of Position Changes and String Changes

Music performance is based on demanding motor control with much practice from young age onward. We have chosen to investigate basic bimanual movements played by violin amateurs and professionals. We posed the question whether position and string changes, two frequent mechanisms, may influence the time interval bowing (right)-fingering (left) coordination. The objective was to measure bimanual coordi­nation, i.e., with or without position changes and string changes. The tendency was that the bimanual coordination was statistically only slightly increased or even unchanged but not perceptible. We conclude that the coordination index is limited up to100 ms intervals, without any erroneous perception. Although the mentioned posi­tion changes and string changes are movements with their timing, they are executed in parallel rather than in series with the bow-fingering coordination

Goal synchronization of bimanual skills depends on proprioception

The present experiments in Human subjects were designed to test whether proprioceptive feedback plays a role in optimising bimanual synchronization in a goal-oriented familiar task. Goal-synchronization is a typical feature of bimanual everyday skills. The purpose of the study was to disturb proprioceptive signalling by means of vibrating the leading left limb while subjects performed a bimanual task on a drawer manipulandum. Blindfolded subjects reached for and opened the drawer with the left hand while the right hand was reaching for grasping an object as the drawer was fully opened. Discrete events of the task were used to measure movement onset times of pulling and grasping hands and of goal arrival times. A spatial–temporal goal invariance was still present despite asymmetrical limb assignments and subjects were blindfolded. In contrast, when vibration (80 Hz) was applied to the forearm flexors of the leading pulling limb, we found that the interval between the hands at goal reaching was significantly prolonged. This suggests that synchronization is not predetermined entirely by feedforward commands and that proprioceptive feedback is necessary for updating an internal forward model and perhaps also for lower-level corrections in order to ensure covariant limb movements for optimal goal-synchronization

Support Stability Influences Postural Responses to Muscle Vibrations in Humans

Abstract We studied the effect of support stability on postural responses to the vibration of Achilles tendons and of neck dorsal muscles in healthy humans. For this purpose we compared postural responses on a rigid floor and on 6 cm high rocking supports (see-saws) of different curvatures (different radii: 30, 60 and 120 cm). The subject stood with eyes closed, the centre of the feet coincided with the centre of the see-saw. We recorded platform tilt, horizontal displacements of the upper body, ankle joint angle and activity of ankle joint muscles. On the rocking platform subjects maintained balance in a sagittal direction by making see-saw rotations placing the support under the body's centre of gravity. Equilibrium maintenance requires that the torque in the ankle joint increases during forward body displacements, as on the rigid floor, and be accompanied by a plantar flexion (not by a dorsiflexion) in the ankle joint. The directional dependence of vibration-induced reactions on the see-saw was the same (relative to space) as on the rigid floor: backward body displacement during Achilles tendon vibration and forward body displacement during neck muscle vibration. A decrease of support stability (with a decrease of the radius from 120 to 30 cm) diminished significantly the effect of Achilles tendon vibration and to a lesser extent the effect of neck muscle vibration. In contrast, the increase of platform stability by hand contact with a stable external object gave rise to prominent body sway in response to Achilles tendon vibration. Neck muscle vibration on the movable support provoked a quick initial forward body sway. This initial quick response was absent during vibration of the Achilles tendons. We conclude that postural responses to muscle vibration reflect the participation of different muscles in posture control and depend on the support properties. Support instability changes the role of proprioceptive information and the state of the system of equilibrium maintenance