Computational Biomechanics Helps to Improve the Shifting Movement in Violin Playing

Abstract

Objetive: One of the movements performed by the violinist is the shifting of position, which is characterized by the translation of the left hand in order to play notes in different places that would not be accessible if the hand was fixed. The purpose of this work was to use computational simulation in biomechanics to understand the movement performed during the shifting, as well as its implications related to joint torque and muscle activation. Methods: Predictive simulations were performed, using a neuromusculoskeletal model of the human arm. The simulations were based on an optimal control problem that seeks to ensure a smooth shifting and minimizing the human effort and the time necessary to accomplish the movement. Two simulations were performed: one considering an ascend shifting and other considering a descend shifting. Results: The results obtained were the motion that the musician need to perform in order to achieve an optimal shifting, the joint torques, the muscles activation and recruitment pattern. The motion obtained can serves as a base for the musician to develop an optimal shifting trajectory. The torques and muscles activations give us an idea of the efforts involved. Muscle recruitment patterns allow us to understand the body's biomechanical behavior for each type of shifting. Conclusion: Through the results obtained, it is possible to conclude that the shifting is a movement with characteristics of instability by nature, needing to be anticipated by the violinist in order to be as close as possible to the optimal condition, guaranteeing good sound and safety in execution.