A comprehensive and volumetric musculoskeletal model for the dynamic simulation of the shoulder function

Péan, Fabien; Tanner, Christine; Gerber, Christian; Fürnstahl, Philipp; Göksel, Orçun

doi:10.1080/10255842.2019.1588963

Cited by 9 publications

(13 citation statements)

References 30 publications

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“…One way to determine a muscle's contribution to a movement is via inverse kinematics and optimisation techniques. Typically, modelling studies assume each muscle to operate as a single contractile unit, whether using 1D Hill-type models or 3D models [27,36]. However, by considering the joint as spanned by groups of motor units instead, the spatial resolution of force production would be greatly increased.…”

Section: Discussionmentioning

confidence: 99%

“…However, such models have largely ignored this feature of muscle contraction [e.g. [29][30][31][32][33][34][35][36] -most likely due to the representation of muscle fibres as a continuous vector field, which makes the inclusion of motor unit anatomy challenging. Currently, only multi-scale continuum mechanical muscle models resolve motor unit anatomy by describing individual muscle fibres [e.g.…”

Section: Introductionmentioning

confidence: 99%

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Modelling motor units in 3D: Influence on muscle contraction and joint force via a proof of concept simulation

Saini

Klotz

Röhrle

2022

Preprint

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Functional heterogeneity of a skeletal muscle refers to its ability to produce a variety of force vectors through the localised, regional recruitment of motor units. Existing three-dimensional, macroscopic, continuum-mechanical muscle models (3D models) neglect motor unit anatomy and are thus ill-suited to investigate a muscle's functional heterogeneity. Here, we develop a method to generate and enrich 3D models with motor unit anatomy and activity information: First, a virtual innervation process is applied to group idealised computational fibres into motor units. Second, the discrete microstructure is homogenised to form continuous volumetric motor unit distributions. Third, motor unit activity is computed as a function of its firing times and twitch properties. As a proof of concept, we generated multiple masticatory models, each with different (masseter) motor unit distributions. The masticatory models were supplied with identical motor unit activity to simulate a sub-maximal static bite. The virtual innervation method captured physiological hallmark features of motor unit anatomy such as size, shape, position, and overlap. We found that motor unit anatomy significantly influenced bite force direction while having minimal impact on magnitude. Motor unit position played a more significant role than motor unit overlap. These results highlight the importance of modelling motor unit anatomy in understanding movement, particularly for muscles with complex internal architecture. This method provides an environment to investigate the interplay between motor control, skeletal muscle mechanics, and joint kinematics. Such investigations are relevant for the functional heterogeneity of healthy and pathological muscles.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modelling motor units in 3D: Influence on muscle contraction and joint force via a proof of concept simulation

Saini

Klotz

Röhrle

2022

Preprint

View full text Add to dashboard Cite

show abstract

“…The above proved the availability of the FE model. Besides, the FE model has been thoroughly applied in constructing a musculoskeletal model for dynamically simulating the shoulder function [ 22 ].…”

Section: Discussionmentioning

confidence: 99%

A finite element model of the shoulder: application to the changes of biomechanical environment induced by postoperative malrotation of humeral shaft fracture

Wang

et al. 2022

BMC Musculoskelet Disord

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Objectives The humerus fracture is one of the most commonly occurring fractures. In this research, we attempted to evaluate and compare the extent of malrotation and biomechanical environment after surgical treatment of humeral shaft fractures. Methods A finite element (FE) model of the shoulder was built based on Computed Tomography (CT) data of a patient with a humeral shaft fracture. The muscle group around the shoulder joint was simulated by spring elements. The changes of shoulder stresses under rotation were analyzed. The biomechanics of the normal shoulder and postoperative malrotation of the humeral shaft was analyzed and compared. Results During rotations, the maximum stress was centered in the posterosuperior part of the glenoid for the normal shoulder. The von Mises shear stresses were 4.40 MPa and 4.89 MPa at 40° of internal and external rotations, respectively. For internal rotation deformity, the shear contact forces were 7–9 times higher for the shoulder internally rotated 40° than for the normal one. For external rotation deformity, the shear contact forces were about 3–5 times higher for the shoulder with 40° external rotation than the normal one. Conclusion Postoperative malrotation of humeral shaft fracture induced the changes of the biomechanical environment of the shoulders. The peak degree of malrotation was correlated with increased stresses of shoulders, which could be paid attention to in humeral shaft fracture treatment. We hoped to provide information about the biomechanical environment of humeral malrotation.

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“…However, such models have largely ignored this feature of muscle contraction (e.g. Johansson et al 2000;Fernandez et al 2005;Blemker and Delp 2005;Röhrle and Pullan 2007;Wu et al 2014;Weickenmeier et al 2017;Chi et al 2010;Péan et al 2019)-most likely due to the representation of muscle fibres as a continuous vector field, which makes the grouping of fibres to define motor unit anatomy challenging. Currently, only multi-scale continuum-mechanical muscle models resolve motor unit anatomy by describing individual muscle fibres (e.g.…”

Section: Introductionmentioning

confidence: 99%

Modelling motor units in 3D: influence on muscle contraction and joint force via a proof of concept simulation

Saini

Klotz

Röhrle

2022

Biomech Model Mechanobiol

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Functional heterogeneity is a skeletal muscle’s ability to generate diverse force vectors through localised motor unit (MU) recruitment. Existing 3D macroscopic continuum-mechanical finite element (FE) muscle models neglect MU anatomy and recruit muscle volume simultaneously, making them unsuitable for studying functional heterogeneity. Here, we develop a method to incorporate MU anatomy and information in 3D models. Virtual fibres in the muscle are grouped into MUs via a novel “virtual innervation” technique, which can control the units’ size, shape, position, and overlap. The discrete MU anatomy is then mapped to the FE mesh via statistical averaging, resulting in a volumetric MU distribution. Mesh dependency is investigated using a 2D idealised model and revealed that the amount of MU overlap is inversely proportional to mesh dependency. Simultaneous recruitment of a MU’s volume implies that action potentials (AP) propagate instantaneously. A 3D idealised model is used to verify this assumption, revealing that neglecting AP propagation results in a slightly less-steady force, advanced in time by approximately 20 ms, at the tendons. Lastly, the method is applied to a 3D, anatomically realistic model of the masticatory system to demonstrate the functional heterogeneity of masseter muscles in producing bite force. We found that the MU anatomy significantly affected bite force direction compared to bite force magnitude. MU position was much more efficacious in bringing about bite force changes than MU overlap. These results highlight the relevance of MU anatomy to muscle function and joint force, particularly for muscles with complex neuromuscular architecture.

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A comprehensive and volumetric musculoskeletal model for the dynamic simulation of the shoulder function

Cited by 9 publications

References 30 publications

Modelling motor units in 3D: Influence on muscle contraction and joint force via a proof of concept simulation

Modelling motor units in 3D: Influence on muscle contraction and joint force via a proof of concept simulation

A finite element model of the shoulder: application to the changes of biomechanical environment induced by postoperative malrotation of humeral shaft fracture

Modelling motor units in 3D: influence on muscle contraction and joint force via a proof of concept simulation

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