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Cheze L.,University Claude Bernard Lyon 1 | Moissenet F.,Laboratoire Danalyse Du Mouvement Et Of La Posture | Dumas R.,University Claude Bernard Lyon 1
Movement and Sports Sciences - Science et Motricite | Year: 2015

The prediction of musculo-tendon forces developed during daily living tasks is essential to assess movement control and joint reaction forces, and then provide insight to improve diagnosis and treatment follow-up of neurological and orthopedic disorders. Direct measurement of the musculo-tendon forces is hardly possible and the redundancy inherent in the musculo-skeletal system yields not enough equilibrium equations to compute these forces. Different methods have been proposed to overcome this problem, requiring numerous input parameters, most of them difficult or impossible to adjust to a specific subject. These methods will be exposed and their limits pointed out. Anyway, further development is needed in order that the model-based prediction of musculo-tendon forces can be used for clinical purposes. © ACAPS, EDP Sciences, 2012. Source


Dumas R.,University of Lyon | Dumas R.,University Claude Bernard Lyon 1 | Dumas R.,Laboratoire Of Biomecanique Et Mecanique Des Chocs Lbmc | Moissenet F.,Laboratoire Danalyse Du Mouvement Et Of La Posture | And 6 more authors.
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | Year: 2014

One of the open issues in musculoskeletal modelling remains the choice of the objective function that is used to solve the muscular redundancy problem. Some authors have recently proposed to introduce joint reaction forces in the objective function, and the question of the weights associated with musculo-tendon forces and joint reaction forces arose. This question typically deals with a multi-objective optimisation problem. The aim of this study is to illustrate, on a planar elbow model, the ensemble of optimal solutions (i.e. Pareto front) and the solution of a global objective method that represent different compromises between musculo-tendon forces, joint compression force, and joint shear force. The solutions of the global objective method, based either on the minimisation of the sum of the squared musculo-tendon forces alone or on the minimisation of the squared joint compression force and shear force together, are in the same range. Minimising either the squared joint compression force or shear force alone leads to extreme force values. The exploration of the compromises between these forces illustrates the existence of major interactions between the muscular and joint structures. Indeed, the joint reaction forces relate to the projection of the sum of the musculo-tendon forces. An illustration of these interactions, due to the projection relation, is that the Pareto front is not a large surface, like in a typical three-objective optimisation, but almost a curve. These interactions, and the possibility to take them into account by a multi-objective optimisation, seem essential for the application of musculoskeletal modelling to joint pathologies. © IMechE 2014. Source


Moissenet F.,Laboratoire Danalyse Du Mouvement Et Of La Posture | Cheze L.,University Claude Bernard Lyon 1 | Cheze L.,University of Lyon | Dumas R.,University Claude Bernard Lyon 1 | Dumas R.,University of Lyon
ASME 2013 Summer Bioengineering Conference, SBC 2013 | Year: 2013

Instrumented prostheses, by measuring joint contact forces during a movement, give nowadays a unique opportunity to validate the ability of musculo-skeletal models in predicting internal forces. In this study, a rigid multi-body musculo-skeletal model, allowing computing the musculo-tendon, joint contact, ligament and bone forces all together by static optimisation, using a weighted criterion, is presented. The results show that the musculo-tendon forces are generally in accordance with the envelopes of the main peaks of the subject's EMG signals and that the amplitudes and patterns of the predicted joint contact, ligament and bone forces are in a good agreement with the measurements and with the literature. By allowing the introduction of other forces than the musculo-tendon forces in the static optimisation, this study opens new horizons in order to better model the human physiology (e.g., joint pain). Copyright © 2013 by ASME. Source


El Habachi A.,University of Lyon | El Habachi A.,University Claude Bernard Lyon 1 | El Habachi A.,Lbmc Laboratoire Of Biomecanique Et Mecanique Des Chocs | Moissenet F.,Laboratoire Danalyse Du Mouvement Et Of La Posture | And 9 more authors.
Medical and Biological Engineering and Computing | Year: 2015

Sensitivity analysis is a typical part of biomechanical models evaluation. For lower limb multi-body models, sensitivity analyses have been mainly performed on musculoskeletal parameters, more rarely on the parameters of the joint models. This study deals with a global sensitivity analysis achieved on a lower limb multi-body model that introduces anatomical constraints at the ankle, tibiofemoral, and patellofemoral joints. The aim of the study was to take into account the uncertainty of parameters (e.g. 2.5 cm on the positions of the skin markers embedded in the segments, 5° on the orientation of hinge axis, 2.5 mm on the origin and insertion of ligaments) using statistical distributions and propagate it through a multi-body optimisation method used for the computation of joint kinematics from skin markers during gait. This will allow us to identify the most influential parameters on the minimum of the objective function of the multi-body optimisation (i.e. the sum of the squared distances between measured and model-determined skin marker positions) and on the joint angles and displacements. To quantify this influence, a Fourier-based algorithm of global sensitivity analysis coupled with a Latin hypercube sampling is used. This sensitivity analysis shows that some parameters of the motor constraints, that is to say the distances between measured and model-determined skin marker positions, and the kinematic constraints are highly influencing the joint kinematics obtained from the lower limb multi-body model, for example, positions of the skin markers embedded in the shank and pelvis, parameters of the patellofemoral hinge axis, and parameters of the ankle and tibiofemoral ligaments. The resulting standard deviations on the joint angles and displacements reach 36° and 12 mm. Therefore, personalisation, customisation or identification of these most sensitive parameters of the lower limb multi-body models may be considered as essential. © 2015, International Federation for Medical and Biological Engineering. Source


Moissenet F.,Laboratoire Danalyse Du Mouvement Et Of La Posture | Cheze L.,University of Lyon | Cheze L.,University Claude Bernard Lyon 1 | Cheze L.,Laboratoire Of Biomecanique Et Mecanique Des Chocs | And 3 more authors.
Journal of Biomechanical Engineering | Year: 2016

While recent literature has clearly demonstrated that an extensive personalization of the musculoskeletal models was necessary to reach high accuracy, several components of the generic models may be further investigated before defining subject-specific parameters. Among others, the choice in muscular geometry and thus the level of muscular redundancy in the model may have a noticeable influence on the predicted musculotendon and joint contact forces. In this context, the aim of this study was to investigate if the level of muscular redundancy can contribute or not to reduce inaccuracies in tibiofemoral contact forces predictions. For that, the dataset disseminated through the Sixth Grand Challenge Competition to Predict In Vivo Knee Loads was applied to a versatile 3D lower limb musculoskeletal model in which two muscular geometries (i.e., two different levels of muscular redundancy) were implemented. This dataset provides tibiofemoral implant measurements for both medial and lateral compartments and thus allows evaluation of the validity of the model predictions. The results suggest that an increase of the level of muscular redundancy corresponds to a better accuracy of total tibiofemoral contact force whatever the gait pattern investigated. However, the medial and lateral contact forces ratio and accuracy were not necessarily improved when increasing the level of muscular redundancy and may thus be attributed to other parameters such as the location of contact points. To conclude, the muscular geometry, among other components of the generic model, has a noticeable impact on joint contact forces predictions and may thus be correctly chosen even before trying to personalize the model. Copyright © 2016 by ASME. Source

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