Critical analysis of musculoskeletal modelling complexity in multibody biomechanical models of the upper limb

Abstract

The inverse dynamics technique applied to musculoskeletal models, and supported by optimisation techniques, is used extensively to estimate muscle and joint reaction forces. However, the solutions of the redundant muscle force sharing problem are sensitive to the detail and modelling assumptions of the models used. This study presents four alternative biomechanical models of the upper limb with different levels of discretisation of muscles by bundles and muscle paths, and their consequences on the estimation of the muscle and joint reaction forces. The muscle force sharing problem is solved for the motions of abduction and anterior flexion, acquired using video imaging, through the minimisation of an objective function describing muscle metabolic energy consumption. While looking for the optimal solution, not only the equations of motion are satisfied but also the stability of the glenohumeral and scapulothoracic joints is preserved. The results show that a lower level of muscle discretisation provides worse estimations regarding the muscle forces. Moreover, the poor discretisation of muscles relevant to the joint in analysis limits the applicability of the biomechanical model. In this study, the biomechanical model of the upper limb describing the infraspinatus by a single bundle could not solve the complete motion of anterior flexion. Despite the small differences in the magnitude of the forces predicted by the biomechanical models with more complex muscular systems, in general, there are no significant variations in the muscular activity of equivalent muscles.

Improving anterior deltoid activity in a musculoskeletal shoulder model – an analysis of the torque-feasible space at the sternoclavicular joint

“…The geometric muscle model of the VHP shoulder model was constructed using the centroid line approach and the guidelines to model muscles with large attachment sites (van der Helm and Veenbaas 1991). Implementations of the VHP model have shown no activation of the DLTa and no solution to the musculo -tendon force coordination problem in certain configurations of the model during simple movements such as abduction and elevation Quental et al 2015). Therefore, using the minimal number of ideal fibres, placed at the centroids, does not guarantee an adequate representation of the musculature.…”

“…An example is the model-estimated DLTa activity. Most models underestimate the DLTa's activity, including the DSEM (van der Helm 1994a, 1994b), VHP (Quental et al 2015) and AnyBody (Sins 2014) models. Therefore, the goal of this paper was to present an analysis of the solution space of the musculo -tendon force coordination problem to determine the cause of DLTa's underestimated activity.…”

“…In vivo measurements have shown the DLTa to contribute significantly to movements of the upper limb such as abduction (Escamilla et al 2009). However, a number of models predict insufficient activity, including the VHP model (Quental et al 2015), the DSEM model (van der Helm 1994a(van der Helm , 1994bQuental et al 2015), the AnyBody model (Sins 2014), the Newcastle model (Masjedi and Johnson 2010) and others (Dickerson et al 2007;Yanagawa et al 2008).…”

A new shoulder model with a biologically inspired glenohumeral joint

“…The GH translations obtained here are compared to those reported in the literature, and the muscle and joint reaction forces are compared to those estimated by the original model of Quental et al . [9,25] , which considers the GH joint as an ideal spherical joint.…”

“…The biomechanical model developed here is based on that of Quental et al . [9,25] , but the contact between the humeral head and the glenoid cavity is described by a mathematical model of a spherical joint with clearance [26,27] . The customization of the features of the spherical joint with clearance allows the simulation of different geometries of the GH joint, including those after an aTSA.…”