1,721,064 research outputs found
Modeling cyclical sport movements - Study of musculoskeletal coordination of the lower limb and spine
No full textL’étude biomécanique d’un mouvement sportif permet d’identifier des paramètres afin de proposer des améliorations pour parfaire la performance et diminuer le risque lésionnel. Pour les mouvements cycliques, une amélioration minime aura un impact fort sur ces deux enjeux du fait de leur répétition. La cinématique articulaire des mouvements à grande amplitude dans le plan sagittal est couramment étudiée bien que la cinématique musculaire sous-jacente n’est pas documentée car les modèles musculo-squelettiques ne sont définis que sur des amplitudes articulaires restreintes. L’étude cinématique en 3 dimensions (3D) est traditionnellement effectuée en laboratoire grâce à des systèmes de capture d’images. Ces outils sont couteux en temps et permettent d’analyser des tâches dans un espace restreint. Le couplage de ces deux niveaux de modélisation doit permette d’identifier les stratégies musculaires individuelles pour générer ces mouvements contraints en condition écologique.Les objectifs de cette thèse sont de développer un protocole afin d’analyser la cinématique musculaire des mouvements cycliques à grandes amplitudes dans le plan sagittal et de développer un modèle de chaine cinématique pour l’étude de mouvement en boucle fermée pour le membre inférieur.Pour cela, un modèle musculo-squelettique spécifique du membre inférieur et du rachis est développé sur OpenSim, une méthodologie propre à l’étude des variations de longueurs est mise en place pour prendre en compte les spécificités intra et interindividuelles et l’impact de la modélisation 3D est discutée par rapport à une modélisation 2D. Le protocole développé est ensuite mis en application lors d’une expérimentation sur ergomètre d’aviron pour 28 rameurs. Enfin, un modèle de chaine cinématique en boucle fermée 3D du membre inférieur est développé et testé avec l’utilisation de centrales inertielles.Ce travail ouvre des perspectives sur les adaptations intra et interindividuelle et le développement d’entraînement adaptés aux contraintes spécifiques de l’activité.The biomechanical study of a sports movement makes it possible to identify parameters in order to propose improvements to enhance performance and reduce the risk of injury. For cyclical movements, a minimal improvement will have a strong impact on these two issues because of their repetition. Joint kinematics of large ranges of motion in the sagittal plane is commonly studied although the underlying muscle kinematics is not documented because musculoskeletal models are only defined on restricted range of motion. The 3 dimensions (3D) kinematic study is traditionally done in the laboratory thanks to motion capture systems. These tools are time consuming and allow analysing tasks in a small space. The coupling of these two levels of modelling must make it possible to identify the individual muscle strategies to generate these constrained movements in ecological condition.The objectives of this thesis are to develop a protocol to analyse the muscle kinematics of cyclic movements at large ranges in the sagittal plane and to develop a kinematic chain model for the study of closed-loop motion for the lower limb.For this, a specific musculoskeletal model of the lower limb and spine is developed on OpenSim, a methodology for the study of length variations is set up to take into account intra- and inter-individual specificities and the impact of 3D modelling is discussed in relation to a 2D modelling. The developed protocol is then applied during a rowing ergometer experiment for 28 rowers. Finally, a closed-loop 3D kinematic chain model of the lower limb is developed and tested with the use of inertial units.These works opens perspectives on intra and inter individual adaptations and training development adapted to the specific constraints of the activity
Biomechanical contribution to kayak activity analysis. Implementation and validation of three-dimensional dynamics measurement
No full textLes méthodes modernes d'entraînement utilisent des appareillages spécifiques appelés ergomètres sur lesquels, en particulier, des programmes d'entraînement et d'évaluation sont proposés par les entraîneurs. De tels dispositifs favorisent la continuité d'un entraînement pendant les périodes peu favorables à une pratique sportive. De même, lorsque ces outils sont instrumentés, ils apportent à l'entraîneur des informations difficilement accessibles en situation réelle de pratique. Ce travail s'inscrit dans cette problématique scientifique dont l'objet est la conception d'un ergomètre pour la pratique du kayak en ligne. Les travaux réalisés ont conduit à la conception d'un ergomètre kayak capable de reproduire les conditions d'une pratique écologique aussi précisément que possible tant d'un point de vue de la gestuelle (cinématique) que des efforts générés (dynamique) d'une part, de proposer et de valider une instrumentation afin de recueillir l'ensemble des efforts d'interaction kayakiste/ergomètre, d'autre part. De plus, cette instrumentation doit être suffisamment exigeante en termes de poids et d'encombrement pour être installée dans un kayak K1 pour réaliser des mesures in situ. Les moyens mis en œuvre donnent accès aux variables biomécaniques permettant de quantifier les éléments de base de la technique de pagayage qui constituent l'ensemble des facteurs déterminants de la performance (force, endurance, technique, etc.). Scientifiques et entraineurs ont ainsi à leur disposition un outil pour une évaluation objective des performances du kayakiste. Ce travail a été réalisé dans le cadre d'une collaboration entre l'axe RoBioss, le CAIPS et la société SENSIX.The modern training methods developed during the last 20 years involve specific equipments named ergometer. These devices allow semi-specific training sessions on a sheltered environment to develop strength during unfavorable periods of in situ practice. They are also more and more used by coaches to evaluate athlete’s skills and aptitudes. Ergometers provide numerical information that cannot be easily measured during in situ sessions. This work is a significant contribution of the following scientific problems; firstly the design of a flat-water kayak ergometer that reproduces accurately on-water conditions, both kinematics and forces generated (dynamic) during the throughout the whole kayaking cycle, secondly, to propose and validate an instrumentation to collect every dynamic interactions between the ergometer and kayaker (hands, seat, feet). In addition, this instrumentation must be design in terms of weight, size and watertightness to be installed in a kayak K1 for in situ measurements. This instrumentation quantifies the basic biomechanics parameters of the kayaking performance such as external forces, endurance, technique, etc. As a result, researchers and coaches will be able to evaluate kayakers’ performance using an unbiased device. This work was conducted as part of a scientific collaboration between the RoBioSS research team, CAIPS and SENSIX compagny
Electromyographic intra individual variability in front crawl swimming
No full textThe purpose of this study was to assess the intra-individual variability of two bilaterally
measured EMG signals (deltoideus medialis and rectus abdominis) in front crawl
swimming and compare the influence of the normalization technique on several variability
measures. Fifteen well-trained adult male competitive swimmers were tested and four
additional measures of variability besides mean and standard deviation were calculated.
The repeatability of swimming movements was high for both tested muscles and one
stroke cycle might be sufficient to determine a swimmers movement pattern. Variance
ratio was suggested as a preferred additional measure of variability as it was least
susceptible to differences in normalization method.status: Publishe
Magnitude and technical characteristics of external force production in the starting blocks: relationship with performance.
Full text linkThe aim of this study was to investigate magnitude and technical characteristics of external force production in the block phase of the sprint start. Nine male sprinters (100 m PB 10.48 ± 0.28 s) performed five to six maximal effort block starts. External force applied to the front and rear blocks were measured using customised instrumented blocks. Average horizontal, vertical and resultant force, and the angle of the resultant force vector underwent correlational analyses with block performance (normalised average horizontal power). Results revealed that front block average horizontal, vertical and resultant force, and rear block angle of the resultant force vector possessed significant relationships with performance, and highlighted that both magnitude and technical characteristics were related to block performance
Perspectives actuelles pour l'analyse, la simulation et la synthèse de mouvements sportifs : Editorial
No full textPrésentation en français et en anglais de ce numéro thématiqu
Measuring impacts and informing modelling processes
Full text linkPrimarily using rugby union situations as case study examples for the practical demonstration, the initial part of the session will discuss both familiar and emerging techniques to measure the biomechanics of sport impact situations. We will cover some of the issues that need to be accounted for to acquire robust data in such complex environments, and we will discuss how experimental measures can be either used in their own right to develop knowledge of impact biomechanics or can provide data to input a modelling pipeline and for model validation purposes
Magnitude and technical characteristics of external force production in the starting blocks: relationship with performance.
Full text linkThe aim of this study was to investigate magnitude and technical characteristics of external force production in the block phase of the sprint start. Nine male sprinters (100 m PB 10.48 ± 0.28 s) performed five to six maximal effort block starts. External force applied to the front and rear blocks were measured using customised instrumented blocks. Average horizontal, vertical and resultant force, and the angle of the resultant force vector underwent correlational analyses with block performance (normalised average horizontal power). Results revealed that front block average horizontal, vertical and resultant force, and rear block angle of the resultant force vector possessed significant relationships with performance, and highlighted that both magnitude and technical characteristics were related to block performance
New insights into lumbar flexion tests based on inverse and direct kinematic musculoskeletal modeling
No full textInternational audienc
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