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

Effect of shoulder model complexity in upper-body kinematics analysis of the golf swing

The golf swing is a complex full body movement during which the spine and shoulders are highly involved. In order to determine shoulder kinematics during this movement, multibody kinematics optimization (MKO) can be recommended to limit the effect of the soft tissue artifact and to avoid joint dislocations or bone penetration in reconstructed kinematics. Classically, in golf biomechanics research, the shoulder is represented by a 3 degrees-of-freedom model representing the glenohumeral joint. More complex and physiological models are already provided in the scientific literature. Particularly, the model used in this study was a full body model and also described motions of clavicles and scapulae. This study aimed at quantifying the effect of utilizing a more complex and physiological shoulder model when studying the golf swing. Results obtained on 20 golfers showed that a more complex and physiologically-accurate model can more efficiently track experimental markers, which resulted in differences in joint kinematics. Hence, the model with 3 degrees-of-freedom between the humerus and the thorax may be inadequate when combined with MKO and a more physiological model would be beneficial. Finally, results would also be improved through a subject-specific approach for the determination of the segment lengths

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

No abstract availabl

Assessment of power losses due to ground contact forces during usual manual wheelchair movements

The aim of this study was to quantify the energy lost during typical daily living activities with a manual wheelchair.‘Fondation du sport français - Henri Sérandour

Changes in Wheelchair Biomechanics Within the First 120 Minutes of Practice: Spatiotemporal Parameters, Handrim Forces, Motor Force, Rolling Resistance and Fore-Aft Stability

Purpose: During manual wheelchair (MWC) skill acquisition, users adapt their propulsion technique through changes in biomechanical parameters. This evolution is assumed to be driven towards a more efficient behavior. However, when no specific training protocol is provided to users, little is known about how they spontaneously adapt during overground MWC locomotion. For that purpose, we investigated this biomechanical spontaneous adaptation within the initial phase of low-intensity uninstructed training. Materials and methods: Eighteen novice able-bodied subjects were enrolled to perform 120min of unin- structed practice with a field MWC, distributed over 4 weeks. Subjects were tested during the very first minutes of the program, and after completion of the entire training protocol. Spatiotemporal parameters, handrim forces, motor force, rolling resistance and fore-aft stability were investigated using an instru- mented field wheelchair. Results: Participants rapidly increased linear velocity of the MWC, thanks to a higher propulsive force. This was achieved thanks to higher handrim forces, combined with an improved fraction of effective force for startup but not for propulsion. Despite changes in mechanical actions exerted by the user on the MWC, rolling resistance remained constant but the stability index was noticeably altered. Conclusion: Even if no indication is given, novice MWC users rapidly change their propulsion technique and increase their linear speed. Such improvements in MWC mobility are allowed by a mastering of the whole range of stability offered by the MWC, which raises the issue of safety on the MWC

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

No abstract availabl

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

Approche numérique pour l’optimisation personnalisée des réglages d’un fauteuil roulant manuel

The study of manual wheelchair (MWC) locomotion biomechanics aims at lowering the risk of upper limbs injuries, by optimizing mobility. Several studies have showed that adjusting MWC settings had an impact on MWC mobility. However, the models used in the literature to depict the « user-MWC » and « MWC-floor » interactions had several limitations. Thus, the first aim of this thesis was to develop a musculoskeletal model of the upper limbs allowing to describe the « user-MWC » interaction, by using adapted experimental methods to apply this model. The second aim of the thesis was to implement a mechanical model of the MWC allowing to compute ground reaction forces during locomotion. The final aim of the thesis was to apply a numerical optimisation procedure, including the models developed during the thesis, to optimize MWC settings. The musculoskeletal model developed during the thesis allowed to analyze biomechanics of the upper limbs during MWC locomotion among subjects recruited during experimental sessions. The MWC settings optimization was implemented with the mechanical model developed during the thesis and confirmed the influence of various MWC settings on mobility. Eventually, improvement perspectives for the numerical optimization procedure of MWC settings were explored, based on predictive movement generation with optimal control algorithms.L’étude de la biomécanique de la locomotion en fauteuil roulant manuel (FRM) a pour objectif de limiter le risque d’apparitions de blessures du membre supérieur, en optimisant la facilité à se déplacer. De nombreuses études ont montré qu’un ajustement des réglages du FRM avait un impact sur la mobilité. Néanmoins, les modèles utilisés dans la littérature pour représenter les interactions « sujet-FRM » et « FRM-environnement » possédaient plusieurs limitations. Ainsi, l’objectif premier de la thèse était la mise en place d’un modèle musculo-squelettique du membre supérieur permettant de modéliser l’interaction entre le sujet et le FRM, en utilisant des méthodes expérimentales adaptées pour appliquer ce modèle. Le second objectif était de construire un modèle mécanique du FRM en mouvement permettant de calculer les forces de réaction entre le sol et les roues du FRM. Le dernier objectif était d’appliquer une procédure d’optimisation numérique des réglages du FRM incluant les modèles développés durant la thèse. Le modèle musculo-squelettique développé a permis d’analyser la biomécanique du membre supérieur lors de la locomotion en FRM chez les sujets recrutés lors des campagnes de mesures. L’optimisation des réglages du FRM a été mise en place à partir du modèle mécanique du FRM, permettant de confirmer l’influence de plusieurs réglages sur la mobilité en FRM. Enfin, des perspectives d’amélioration de la procédure d’optimisation des réglages ont été explorées, à partir d’algorithmes de génération prédictive du mouvement

Numerical approach for subject-specific optimization of manual wheelchair settings

L’étude de la biomécanique de la locomotion en fauteuil roulant manuel (FRM) a pour objectif de limiter le risque d’apparitions de blessures du membre supérieur, en optimisant la facilité à se déplacer. De nombreuses études ont montré qu’un ajustement des réglages du FRM avait un impact sur la mobilité. Néanmoins, les modèles utilisés dans la littérature pour représenter les interactions « sujet-FRM » et « FRM-environnement » possédaient plusieurs limitations. Ainsi, l’objectif premier de la thèse était la mise en place d’un modèle musculo-squelettique du membre supérieur permettant de modéliser l’interaction entre le sujet et le FRM, en utilisant des méthodes expérimentales adaptées pour appliquer ce modèle. Le second objectif était de construire un modèle mécanique du FRM en mouvement permettant de calculer les forces de réaction entre le sol et les roues du FRM. Le dernier objectif était d’appliquer une procédure d’optimisation numérique des réglages du FRM incluant les modèles développés durant la thèse. Le modèle musculo-squelettique développé a permis d’analyser la biomécanique du membre supérieur lors de la locomotion en FRM chez les sujets recrutés lors des campagnes de mesures. L’optimisation des réglages du FRM a été mise en place à partir du modèle mécanique du FRM, permettant de confirmer l’influence de plusieurs réglages sur la mobilité en FRM. Enfin, des perspectives d’amélioration de la procédure d’optimisation des réglages ont été explorées, à partir d’algorithmes de génération prédictive du mouvement.The study of manual wheelchair (MWC) locomotion biomechanics aims at lowering the risk of upper limbs injuries, by optimizing mobility. Several studies have showed that adjusting MWC settings had an impact on MWC mobility. However, the models used in the literature to depict the « user-MWC » and « MWC-floor » interactions had several limitations. Thus, the first aim of this thesis was to develop a musculoskeletal model of the upper limbs allowing to describe the « user-MWC » interaction, by using adapted experimental methods to apply this model. The second aim of the thesis was to implement a mechanical model of the MWC allowing to compute ground reaction forces during locomotion. The final aim of the thesis was to apply a numerical optimisation procedure, including the models developed during the thesis, to optimize MWC settings. The musculoskeletal model developed during the thesis allowed to analyze biomechanics of the upper limbs during MWC locomotion among subjects recruited during experimental sessions. The MWC settings optimization was implemented with the mechanical model developed during the thesis and confirmed the influence of various MWC settings on mobility. Eventually, improvement perspectives for the numerical optimization procedure of MWC settings were explored, based on predictive movement generation with optimal control algorithms

Optimal Control Formulation for Manual Wheelchair Locomotion Simulations: Influence of Anteroposterior Stability

International audienceAbstract Manual wheelchair (MWC) locomotion exposes the user's upper-body to large and repetitive loads, which can lead to upper limbs pain and injuries. A thinner understanding of the influence of MWC settings on propulsion biomechanics could allow for a better adaptation of MWC configuration to the user, thus limiting the risk of developing such injuries. Advantageously compared to experimental studies, simulation methods allow numerous configurations to be tested. Recent studies have developed predictive locomotion simulation using optimal control methods. However, those models do not consider MWC anteroposterior stability, potentially resulting in unreasonable propulsion strategies. To this extent, this study aimed at confirming if constraining MWC anteroposterior stability in the optimal control formulation could lead to a different simulated movement. For this purpose, a four-link rigid-body system was used in a forward dynamics optimization paired with an anteroposterior stability constraint to predict MWC locomotion dynamics of the upper limbs during both startup and steady-state propulsion. Simulation results indicated the occurrence of MWC tipping when stability was not constrained, and that the constrained optimal control algorithm predicted different propulsion strategies. Hence, further proceedings of MWC locomotion simulation and optimal control investigations should take the anteroposterior stability into account to achieve more realistic simulations. Additionally, the implementation of the anteroposterior stability constrains unexpectedly resulted in a reduction of the computational time