Méthode inverse pour la caractérisation du comportement de l'articulation du genou lors de rééducation

International audienceBien qu'elle soit largement étudiée dans la littérature, l'articulation du genou soulève encore de nombreuses questions quant à son comportement biomécanique et à sa rééducation. Située sur l'axe mécanique reliant la hanche et la cheville, elle doit, tout en assurant une grande mobilité au membre inférieur, supporter des actions mécaniques bien supérieures à celles engendrées par le simple poids du corps. Cette articulation, peu congruente comparée à l'articulation de la hanche et d'une structure plus complexe, est le lieu de nombreuses pathologies invalidantes d'origine biomécanique: chondrophaties articulaires, ruptures ligamentaires et des ménisques, luxation rotulienne. Isolée du système musculaire qui la contrôle, l'articulation du genou est un mécanisme instable. Les surfaces de contact (surfaces articulaires) entre fémur et tibia, et entre fémur et rotule sont géométriquement complexes. Leur cohésion est assurée par des liens déformables, les ligaments, composés de plusieurs faisceaux fibreux non parallèles entre eux. Le comportement mécanique de cette articulation est lié à la fois aux formes des surfaces articulaires en présence et à l'architecture des ligaments ainsi qu'à leurs raideurs respectives. Par une approche inverse du mouvement cinématique et statique du genou du patient en rééducation nous proposons de modéliser par simulation numérique de l'articulation du genou en s'appuyant sur une validation expérimentale réalisée au laboratoire LACM de l'URCA [1]. Cette modélisation est destinée à étudier l'impact de la géométrie osseuse et ligamentaire sur la cinématique intrinsèque de l'articulation afin de mieux comprendre son fonctionnement et le rôle des éléments la constituant. A terme, un tel modèle permet une compréhension fine de son fonctionnement et un meilleur diagnostic de ses pathologies et peut présenter un intérêt majeur pour la chirurgie réparatrice du genou et la conception des prothèses articulaires. La modélisation du comportement mécanique local du tibia et du fémur est basée sur des essais expérimentaux de micro-indentation sur os cortical. Les algorithmes d'optimisation (génétique) sont utilisés pour identifiés les paramètres matériau de l'os [2]. Le modèle développé est utilisé pour étudier par technique inverse l'impact de la géométrie osseuse et du comportement mécanique d'interface entre chaque élément (tibia, fémur, péroné, ménisque et ligaments) sur la cinématique intrinsèque 3D de l'articulation afin de mieux comprendre son fonctionnement et le rôle de chaque élément sur la rééducation des patients (voir figure ci-dessous) [3, 4]. Des comparaisons avec les résultats issus des essais réels de laboratoire sont effectuées sur les réponses globales des forces en fonction des déplacements au niveau des articulations

Whole-Body Vibration Exercise as an Intervention to Improve Musculoskeletal Performance

The exposure of individuals to mechanical vibrations produced in vibrating platform can generate whole-body vibration (WBV) exercise. This modality of exercise represents a less tiring alternative to sport, which could benefit mechanical human behavior and prevent sports injuries and musculoskeletal disorders. The specificity of the human body, articulated and connected segments, requires to take into account the biomechanical parameters in protocols involving WBV exercise. Moreover, work time, rest time between the bouts in each session number of sessions, extension of the intervention, and week periodicity must be also well established. Responses to WBV exercise are observed at musculoskeletal, neurological, endocrinological and vascular levels. With respect to the musculoskeletal level, it is verified increase of muscle strength, endurance and power, improvement of the balance, increase of bone mineral density and the decrease of risk of falls. There are several tools to evaluate the responses of the body to WBV exercise. The aim of this chapter is to highlight the relevance of the WBV exercise as an intervention of the physical therapy for the better human optimization

Long jump training emphasizing plyometric exercises is more effective than traditional long jump training: A randomized controlled trial

The aim of the study was to evaluate the impact of an 8-weeksplyometric training program on the sprint and jump performance. The intervention study employed a controlled experimental design with two parallel groups of male long jumpers. While the experimental group (n = 18) trained with plyometric exercises, the control group (n=10) performed classical long jump training. Both groups were examined for athletic performance (30m sprint, standing long jump, vertical jump) and biomechanical parameters of a long-jump movement (max vertical height, horizontal and vertical velocity at take-off, flight time, take-off duration) prior and following the intervention. The experimental group demonstrated significantly better developments than the control group in most of the physical and biomechanical parameters respectively and improved their long jump records. Combining an 8-weeksplyometricprogram with athletics training significantly develops long jump and general athletic performance as well as biomechanical parameters. Therefore, plyometric training can be recommended to athletics coaches as an additional training alternative to improve sprint and long jump abilities in athletes

Integrative Neuromuscular Training in Young Athletes, Injury Prevention, and Performance Optimization: A Systematic Review

The aim of this systematic review was to evaluate the current evidence by assessing the effectiveness of integrative neuromuscular training programs in injury prevention and sports performance in young athletes. Different data sources were analyzed up to January 2018. Eligible studiescontainedinformationonpopulation(youngathletes), intervention (neuromusculartraining), comparator (control group or another exercise intervention), outcomes (injury prevention or sport performance), and study design (randomized trials or prospective studies). The trials were restricted basedonthelanguage(English)andforpublicationdate(after1January2007). Fourteenrandomized controlled trials were included: Seven included dynamic stability-related outcomes. Three assessed the coordination performing fundamental movements and sport-specific skills, while other five studies analyzed muscle strength and two assessed plyometric tests. Agility was evaluated in three studiesandspeedtestswerealsoconsideredbyfourstudies. Finally,fatigueresistanceinthreestudies and injury risk in four were assessed. This review provides evidence that integrative neuromuscular training programs can enhance performance and injury prevention in young athletes, taken into account that adherence to the training program is adequate. Collectively, well-designed, randomized studies are necessary to collaborate with the present findings

Obesity: The Relationship between Growth Hormone and Exercises

Obesity is one of the main causes of death around the world. Moreover, considering the cardiometabolic risk (CMR), the relationship between obesity and CMR is well-established, and the location of adipose tissue (AT), particularly in the abdominal region, is considered an important predictor of metabolic dysfunction than total fat mass. Central obesity can be related to abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT). The relationship between SAT and CMR is not still clear, but the VAT has been considered a unique pathogenic fat depot. In this context, it is important to identify clinical interventions that could be used to improve the management of obesity. The aim of this chapter is to integrate knowledge about the relevance of exercises and/or growth hormone (GH) to the management of individuals with obesity. In conclusion, it appears that exercise-induced reductions in VAT are mediated by induced changes in GH levels. This could be due to the similar lipolytic effects of both GH and exercise on VAT and this relationship would benefit the role of exercise as an intervention against obesity. Preventing and understanding the development of obesity is therefore essential if it is wanted to curb the global epidemic and save social security several million costs concerning health problems