Simulating pinch grip of string instrumentalists: Integration of fatigue into a musculoskeletal model of the fingers
File(s)
Author(s)
Wanglertpanich, Kiatbodin
Type
Thesis
Abstract
Muscle fatigue in string instrumentalists is caused by long periods of playing their instruments during practices or stage performances. Fatigue can be assessed using external – fatigue index (FI) and maximum endurance time (MET) – and internal – surface electromyography (sEMG) – factors. Twenty-two participants performed five static (from 30% to 70% maximum pinch force (MPF)) and one alternating (at 50% MPF) endurance isometric pinch grip with the thumb and index finger. sEMG sensors recorded the muscle activity of seven extrinsic and two intrinsic muscles that actuated thumb and index finger motion. The MET was exponentially and inversely related to the levels of sub-maximum endurance trials and was modelled using exponential regression. However, the FIs after the endurance trials showed that the MPFs did not drop to the forces of the sub-maximum endurance trials themselves. After completing fatiguing trials, participants’ approach to pinch may change, resulting in altered kinematics and/or muscle synergies when performing MPF tasks. Increases in sEMG amplitude over the course of the submaximum endurance trials confirmed that more electric stimulation arose to compensate for losses in muscle force capacity. Muscles accumulated by-product metabolites, which result in drops in sEMG median frequency. Kinematics of the left thumb and index fingers were input into a new
musculoskeletal model with an integrated fatigue model. The MET results were used to calibrate a decay factor in the fatigue model. The fatigue model simulated decreases in maximum muscle tension during sustained fatiguing trials and numerically regulated drops in that maximum. In future work, physiological effects and dynamics motion need to be considered in the model to better simulate realistic hand activities of string instrumentalists.
musculoskeletal model with an integrated fatigue model. The MET results were used to calibrate a decay factor in the fatigue model. The fatigue model simulated decreases in maximum muscle tension during sustained fatiguing trials and numerically regulated drops in that maximum. In future work, physiological effects and dynamics motion need to be considered in the model to better simulate realistic hand activities of string instrumentalists.
Version
Open Access
Date Issued
2024-09-06
Date Awarded
01/12/2024
License URL
Advisor
Kedgley, Angela
Sponsor
Thailand
Publisher Department
Bioengineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)