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A biomechanical model to simulate the effect of a high vertical loading on trunk flexural stiffness |
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| Authors: | Sadok Mehrez Hichem Smaoui Fatma Z. Ben Salah |
| Affiliation: | 1. Polytechnic School of Tunisia, Rue El-Khawarizmi, B.P. 743, La Marsa 2078, Tunisiasadok.mehrez@isetn.rnu.tn;3. College of Engineering, Salman Bin Abdulaziz University, Al-kharj 11942, Saudi Arabia;4. Mohamed Kassab Orthopedics Institute, Route de Ksar Sa?d, La Manouba 2010, Tunisia |
| Abstract: | A human trunk model was developed to simulate the effect of a high vertical loading on trunk flexural stiffness. A force–length relationship is attributed to each muscle of the multi-body model. Trunk stiffness and muscle forces were evaluated experimentally and numerically for various applied loads. Experimental evaluation of trunk stiffness was carried out by measuring changes in reaction force following a sudden horizontal displacement at the T10 level prior to paraspinal reflexes induction. Results showed that the trunk stiffness increases under small applied loads, peaks when the loads were further increased and decreases when higher loads are applied. A sensitivity analysis to muscle force–length relationship is provided to determine the model's limitations. This model pointed out the importance of taking into account the changes in muscle length to evaluate the effect of spinal loads beyond the safe limit that cannot be evaluated experimentally and to predict the trunk instability under vertical load. |
| Keywords: | trunk model muscle force–length relationship trunk stiffness paraspinal reflexes instability |