A case study with custom : a comparison of normal and altered gait with an ankle brace

International audienc

On the influence of the shoulder kinematic chain on joint kinematics and musculotendon lengths during wheelchair propulsion estimated from multibody kinematics optimization

Multibody kinematic optimization is frequently used to assess shoulder kinematics during manual wheelchair (MWC) propulsion but multiple kinematics chains are available. It is hypothesized that these different kinematic chains affect marker tracking, shoulder kinematics and resulting musculotendon (MT) lengths. In this study, shoulder kinematics and MT lengths obtained from four shoulder kinematic chains (open-loop thorax-clavicle-scapula-humerus (M1), closed-loop with contact ellipsoid (M2), scapula rhythm from regression equations (M3), and a single ball-and- socket joint between the thorax and the humerus (M4) were compared. Right-side shoulder kinematics from seven subjects were obtained with 34 reflective markers and a scapula locator using an optoelectronic motion capture system while propelling on a MWC simulator. Data was processed based on the four models. Results showed the impact of shoulder kinematic chains on all studied variables. Marker reconstruction errors were found similar between M1 and M2 and lower than for M3 and M4. Few degrees of freedom (DoF) were noticeably different between M1 and M2, but all shoulder DoFs were significantly affected between M1 and M4. As a consequence of differences in joint kinematics, MT lengths were affected by the kinematic chain definition. The contact ellipsoid (M2) was found as a good trade-off between marker tracking and penetration avoidance of the scapula. The regression-based model (M3) was less efficient due to limited humerus elevation during MWC propulsion, as well as the ball-and-socket model (M4) which appeared not suitable for upper limbs activities, including MWC propulsion.This study has been self-funded by the Centre d'Etude et de Recherche sur l'Appareillage des Handicapés (Institution Nationale des Invalides), Créteil, France

Tracking the scapula motion through multibody kinematics optimisation to study manual wheelchair propulsion

No abstract availabl

Accuracy and kinematics consistency of marker-based scaling approaches on a lower limb model: a comparative study with imagery data

Medical images are not typically included in protocol of motion laboratories. Thus, accurate scaling of musculoskeletal models from optoelectronic data are important for any biomechanical analysis. The aim of the current study was to identify a scaling method based on optoelectronic data, inspired from literature, which could offer the best trade-off between accurate geometrical parameters (segment lengths, orientation of joint axes, marker coordinates) and consistent inverse kinematics outputs (kinematic error, joint angles). The methods were applied on 26 subjects and assessed with medical imagery building EOS-based models, considered as a reference. The main contribution of this paper is to show that the marker-based scaling followed by an optimisation of orientation joint axes and markers local coordinates, gives the most consistent scaling and joint angles with EOS-based models. Thus, when a non-invasive mean with an optoelectronic system is considered, a marker-based scaling is preliminary needed to get accurate segment lengths and to optimise joint axes and marker local coordinates to reduce kinematic errors.AbbrevationsAJCAnkle joint centreCKEcumulative kinematic errorDoFdegree of freedomEBEOS-basedHBheight-basedHJChip joint centreKJCknee joint centreMBmarker-basedMSMmusculoskeletal modelsSPMstatistical parametric mappingSTAsoft tissue artifactEBa.m∗EOS-based with optimised joint axes, and all model markers coordinatesMBa.m∗marker-based with optimised joint axes, and all model markers coordinatesMBl.a.mmarker-based with optimised segment lengths, joint axes, and selected model markers coordinatesASISanterior superior illiac spine PSIS posterior superior illiac spine

Effects of ellipsoid parameters on scapula motion during manual wheelchair propulsion based on multibody kinematics optimization. A preliminary study

No abstract availabl

Impact of osteopathic manipulative treatment on range of motion of the pelvis during the one-sided tilt test: a pilot study

International audienc

Comparison of shoulder kinematic chain models and their influence on kinematics and kinetics in the study of manual wheelchair propulsion

Several kinematic chains of the upper limbs have been designed in musculoskeletal models to investi- gate various upper extremity activities, including manual wheelchair propulsion. The aim of our study was to compare the effect of an ellipsoid mobilizer formulation to describe the motion of the scapu- lothoracic joint with respect to regression-based models on shoulder kinematics, shoulder kinetics and computational time, during manual wheelchair propulsion activities. Ten subjects, familiar with manual wheelchair propulsion, were equipped with reflective markers and performed start-up and propulsion cycles with an instrumented field wheelchair. Kinematic data obtained from the optoelectronic system and kinetic data measured by the sensors on the wheelchair were processed using the OpenSim software with three shoulder joint modeling versions (ellipsoid mobilizer, regression equations or fixed scapula) of an upper-limb musculoskeletal model. As expected, the results obtained with the three versions of the model varied, for both segment kinematics and shoulder kinetics. With respect to the model based on regression equations, the model describing the scapulothoracic joint as an ellipsoid could capture the kinematics of the upper limbs with higher fidelity. In addition, the mobilizer formulation allowed to com- pute consistent shoulder moments at a low computer processing cost. Further developments should be made to allow a subject-specific definition of the kinematic chain

Generic and specific musculoskeletal modeling for the support of the soldier's physical activity

Le port d’un exosquelette d’assistance à la locomotion permet d’envisager une plus grande mobilité du soldat, de décharger les articulations, de limiter l’apparition de la fatigue musculaire et de limiter la dépense énergétique. En revanche, la conception des exosquelettes d’assistance à la locomotion à des fins militaires est soumise à de fortes contraintes qui rendent le déploiement d’exosquelette difficile. Ainsi, la modélisation musculo-squelettique est envisagée comme un outil pour la conception et l’évaluation afin d'optimiser et de quantifier les bénéfices biomécaniques pour les futurs utilisateurs.Dans cette thèse, on se propose de relever deux défis génériques et spécifiques liés à la modélisation musculo-squelettique. Le premier défi se propose d’identifier des gammes de modèles représentatives de la population et de définir des lois de régression morphologiques génériques pour le soldat. Le deuxième défi consiste à mettre en place des méthodes de personnalisation géométrique et musculaire des modèles musculo-squelettiques. Ces méthodes sont essentielles pour effectuer des simulations musculo-squelettiques cohérentes et pour permettre la conception et l’évaluation des exosquelettes.Wearing a locomotion assistance exoskeleton allows to envisage a greater mobility of the soldier, to unload the joints, to limit the appearance of muscle fatigue and to limit energy expenditure. On the other hand, the design of locomotion assistance exoskeletons for military purposes is subject to strong constraints that make the deployment of exoskeletons difficult. Thus, musculoskeletal modelling is considered as a tool for the design and evaluation of exoskeletons to optimise and quantify the biomechanical benefits for future users.In this thesis, two generic and specific challenges related to musculoskeletal modelling are tackled. The first challenge intends to identify ranges of models representative of the population and to define generic morphological regression laws for the soldier. The second challenge is to implement methods for geometric and muscular personalization of musculoskeletal models. These methods are essential to perform consistent musculoskeletal simulations and to allow for the design and evaluation of exoskeletons

Modélisation musculo-squelettique générique et spécifique en vue du support de l’activité physique du soldat

Wearing a locomotion assistance exoskeleton allows to envisage a greater mobility of the soldier, to unload the joints, to limit the appearance of muscle fatigue and to limit energy expenditure. On the other hand, the design of locomotion assistance exoskeletons for military purposes is subject to strong constraints that make the deployment of exoskeletons difficult. Thus, musculoskeletal modelling is considered as a tool for the design and evaluation of exoskeletons to optimise and quantify the biomechanical benefits for future users.In this thesis, two generic and specific challenges related to musculoskeletal modelling are tackled. The first challenge intends to identify ranges of models representative of the population and to define generic morphological regression laws for the soldier. The second challenge is to implement methods for geometric and muscular personalization of musculoskeletal models. These methods are essential to perform consistent musculoskeletal simulations and to allow for the design and evaluation of exoskeletons.Le port d’un exosquelette d’assistance à la locomotion permet d’envisager une plus grande mobilité du soldat, de décharger les articulations, de limiter l’apparition de la fatigue musculaire et de limiter la dépense énergétique. En revanche, la conception des exosquelettes d’assistance à la locomotion à des fins militaires est soumise à de fortes contraintes qui rendent le déploiement d’exosquelette difficile. Ainsi, la modélisation musculo-squelettique est envisagée comme un outil pour la conception et l’évaluation afin d'optimiser et de quantifier les bénéfices biomécaniques pour les futurs utilisateurs.Dans cette thèse, on se propose de relever deux défis génériques et spécifiques liés à la modélisation musculo-squelettique. Le premier défi se propose d’identifier des gammes de modèles représentatives de la population et de définir des lois de régression morphologiques génériques pour le soldat. Le deuxième défi consiste à mettre en place des méthodes de personnalisation géométrique et musculaire des modèles musculo-squelettiques. Ces méthodes sont essentielles pour effectuer des simulations musculo-squelettiques cohérentes et pour permettre la conception et l’évaluation des exosquelettes