Effect of intervertebral translational flexibilities on estimations of trunk muscle forces, kinematics, loads, and stability

Auteurs

Farshid Ghezelbash, Department of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, Tehran, 11155-9567, Iran
Navid Arjmand, Department of Mechanical Engineering, Sharif University of Technology, Azadi Avenue, Tehran, 11155-9567, Iran
Aboulfazl Shirazi-Adl, Division of Applied Mechanics, Department of Mechanical Engineering, École Polytechnique, C.P. 6079, Succ. Centre-ville, Montréal, H3C 3A7, QC, Canada

Type de document

Études primaires

Année de publication

2015

Langue

Anglais

Titre de la revue

Computer Methods in Biomechanics and Biomedical Engineering

Première page

1760

Dernière page

1767

Résumé

Due to the complexity of the human spinal motion segments, the intervertebral joints are often simulated in the musculoskeletal trunk models as pivots thus allowing no translational degrees of freedom (DOFs). This work aims to investigate, for the first time, the effect of such widely used assumption on trunk muscle forces, spinal loads, kinematics, and stability during a number of static activities. To address this, the shear deformable beam elements used in our nonlinear finite element (OFE) musculoskeletal model of the trunk were either substantially stiffened in translational directions (SFE model) or replaced by hinge joints interconnected through rotational springs (HFE model). Results indicated that ignoring intervertebral translational DOFs had in general low to moderate impact on model predictions. Compared with the OFE model, the SFE and HFE models predicted generally larger L4–L5 and L5–S1 compression and shear loads, especially for tasks with greater trunk angles; differences reached ∼15% for the L4–L5 compression, ∼36% for the L4–L5 shear and ∼18% for the L5–S1 shear loads. Such differences increased, as location of the hinge joints in the HFE model moved from the mid-disc height to either the lower or upper endplates. Stability analyses of these models for some select activities revealed small changes in predicted margin of stability. Model studies dealing exclusively with the estimation of spinal loads and/or stability may, hence with small loss of accuracy, neglect intervertebral translational DOFs at smaller trunk flexion angles for the sake of computational simplicity. © 2014, © 2014 Taylor & Francis.

Mots-clés

Colonne vertébrale, Spinal column, Modèle, Model, Optimisation, Optimization, Force musculaire, Muscular strength

Numéro de projet IRSST

n/a

Citation recommandée

Ghezelbash, F., Arjmand, N. et Shirazi-Adl, A. (2015). Effect of intervertebral translational flexibilities on estimations of trunk muscle forces, kinematics, loads, and stability. Computer Methods in Biomechanics and Biomedical Engineering, 18(16), 1760-1767. https://doi.org/10.1080/10255842.2014.961440