Nicolas Forestier

Université Savoie Mont Blanc | UdS · Laboratoire Inter universitaire de Biologie de la Motricité

Background After anterior cruciate ligament reconstruction (ACLR), the risk of recurrence can reach 20%, partially due to poor postural control and impaired sensory processing. Lack of flexibility in proprioceptive postural strategy has recently been shown to be a potential risk factor for ACL injury. Hypothesis/Purpose This study aimed to compare...

A B S T R A C T Objective: An optimal proprioceptive reweighting strategy is necessary to maintain posture. A suboptimal strategy was associated with injury determinants and whether the strategy can be modified is unknown. Muscle fatigue can be used to investigate proprioceptive reweighting. The aims of this study were to evaluate the effects of lo...

Introduction Anterior cruciate ligament (ACL) injuries are frequent in handball and altered sensory integration may contribute to increased injury risk. Recent evidence showed that proprioceptive postural control strategies differ among athletes. The aim of this study was to evaluate the relationship between proprioceptive strategy and biomechanics...

INTRODUCTION: Anterior cruciate ligament (ACL) injuries are frequent in team sports, especially during side-cutting ma-noeuvres (1). Altered sensory integration contributes to increased injury risk (2) and several biomechanical determinants have been previously associated with the occurrence of ACL ruptures (3). Recent data has shown that proprioce...

Introduction : Bien que la proprioception soit utilisée dans le champ de la pratique clinique, certaines ambiguïtés demeurent concernant les méthodes et les exercices mis en place. Si les protocoles de mesure de l’acuité proprioceptive sont connus ceux relatifs aux capacités d’intégration proprioceptive le sont moins. Objectifs : Cet article de syn...

Background Lower extremity injuries among young female handball players are very common. The modified Star Excursion Balance Test (mSEBT) is a valid clinical tool to assess dynamic postural control and identify athletes with higher risk of injury. However, its interpretation is difficult since performance on this test is highly sport dependent. No...

Le handball est un des sports les plus pourvoyeurs de ruptures du ligament croisé antérieur (LCA). Les données récentes indiquent que le système nerveux central est impliqué dans la survenue de la lésion, en particulier les zones responsables de l’intégration sensorielle. L’objectif de cette thèse est d’évaluer l’influence des capacités d’intégrati...

Postural control during complex tasks requires adequate sensory integration and somaesthetic reweighting: suboptimal postural strategies can lead to injury. We assessed the ability of healthy athletes to reweight somaesthetic signals during postural perturbations on different surfaces. Thirty-five young (16±1 years), healthy, elite handball players...

Background The ability to dynamically reintegrate proprioceptive signals after they have been perturbated is impaired in certain pathologies. Evaluation of proprioceptive reintegration is useful for clinical practice but currently requires expensive laboratory tools. We developed a simple method, accessible to clinicians. Research question: Is two-...

The Star Excursion Balance Test (SEBT) is a reliable, responsive, and clinically relevant functional assessment of lower limbs' dynamic postural control. However, great disparity exists regarding its methodology and the reported outcomes. Large and specific databases from various population (sport, age, and gender) are needed to help clinicians whe...

Facing a chronic ankle instability, an early neuromuscular reprogramming is mandatory to restore the active joint protection system. Specifically, it means strengthening the ankle stabilizing muscles (evertor) associated with proprioceptive work. There is a lack of specificity of the commonly used tools as the restoration of proprioceptive acuity n...

As voluntary muscle fatigue increases, the perception of the effort required to produce a particular level of force also increases. This occurs because we produce greater neural outputs from the brain to compensate for the fatigue-induced loss of force. Muscle fatigue can also be generated following bouts of neuromuscular electrical stimulation (NM...

Background: The Star Excursion Balance Test is a reliable test to assess the dynamic postural control of the lower limb and screen athlete for injury risk. However, performances on this test appear to be different according to sport, sex and level of activity. Lower limb injuries such as ankle sprain and anterior cruciate ligament rupture are frequ...

Introduction: The Star Excursion Balance Test (SEBT) is a func-tional test described 25 years ago and is commonly used in the literature to quantify the dynamic postural control of the lower limb. However, great disparity exists among studies regarding the methodology of the test as well as results obtained in the literature. This study aims to pr...

The origin of the sense of effort has been debated for several decades and there is still no consensus among researchers regarding the underlying neural mechanisms. Some advocate that effort perception mainly arises from an efference copy originating within the brain while others believe that it is predominantly carried by muscle afferent signals....

Ankle instability and orthotics.: The wearing of ankle orthoses is becoming increasingly common in team and combat sports (tennis, badminton). Their role in the primary prevention of sprains has not been clearly established, while their role in secondary prevention seems to depend on their rigidity. A rigid orthosis, however, affects performance. T...

This study was designed to explore the effects of intrafusal thixotropy, a property affecting muscle spindle sensitivity, on the sense of force. For this purpose, psychophysical measurements of force perception were performed using an isometric force matching paradigm of elbow flexors consisting of matching different force magnitudes (5, 10 and 20%...

A variety of mechanisms have been proposed as causes for Chronic Ankle Instability (CAI), including the delayed neuromuscular response of ankle evertors, a deficit in corticomotor excitability, or weakness of these muscles. Studies dealing with the strength evaluation of ankle evertors have classically been based on isokinetic tests and reported co...

Introduction : L’entorse latérale de cheville est une des blessures les plus communes rencontrées dans la pratique sportive. Le strapping est un outil utilisé comme une aide au retour sur le terrain et il est communément admis que son efficacité pour contrôler l’inversion de cheville est de moins de 30 minutes. Objectif : Cette étude a été mise en...

We investigated whether and how the movement initiation condition (IC) encountered during the early movements performed following focal muscle fatigue affects the postural control of discrete ballistic movements. For this purpose, subjects performed shoulder flexions in a standing posture at maximal velocity under two movement IC, i.e., in self-pac...

Introduction Le principal mecanisme a l’origine des douleurs d’epaule, considerees comme un fleau societal [1], est le conflit sous-acromial (CSA). Il est associe a la reduction de l’espace sous-acromial par decentrage de la tete humerale sur la glene de la scapula [2]. La reduction des mobilites actives de l’epaule generees par le CSA a un fort im...

Introduction Si certains travaux suggèrent fortement l’existence d’une faiblesse des éverseurs chez les patients en instabilité chronique de cheville (ICC) [1], il n’existe pas de consensus lorsque la performance isocinétique des éverseurs de tels patients est comparée à celle de sujets sains (eg. [2,3] vs. [4,5]). Certains auteurs attribuent ces r...

Reflexion sur la pertinence et la limite d’utilisation du temps de réaction péronéen comme indicateur des qualités sensori-motrices de la cheville.

Background: Ankle movements can be partially encoded by cutaneous afferents. However, little is known about the central integration of these cutaneous signals, and whether individual differences exist in this integration. The aim of this study was to determine whether the effect of cutaneous stimulation at the ankle would differ depending on the p...

Background: Ankle sprain is the most common sport-related injury and eccentric weakness of ankle evertors is regarded as a significant muscular deficit related to chronic ankle instability. However, the eccentric performance of the evertors is rarely assessed by clinicians because procedures used for research purposes (i.e. isokinetic tests) are n...

Introduction : Musculoskeletal disorders account for 85% of occupational diseases and more than one employee out of two suffers from this kind of problem. Upper trapezius myalgia, which is the consequence of continuous muscular activation, is one of the most frequent. Few studies have investigated the effect of posture on upper trapezius muscles so...

Muscle fatigue modifies the gain between motor command magnitude and the mechanical muscular response. In other words, post-fatigue, central drives to the muscles must increase to maintain a particular submaximum mechanical output. In this study, we tested the hypothesis that this modified gain can be predicted by the central nervous system (CNS) d...

The success of any surgical intervention is narrowly linked to the operating comfort of the surgeon. Nicknamed "chicken wings", the typical posture adopted by a practitioner during a laparoscopic intervention leads to cervical, shoulders and back pains. To avoid such a posture is one of the main challenge of medical devices designers. Instruments l...

External ankle supports, such as ankle braces, may improve postural stability by stimulating cutaneous receptors. It remains unknown whether these supports have an effect on the posture central regulation. The aim of this study was to determine the effect of wearing a soft ankle brace on soleus H-reflex amplitude and presynaptic inhibition during s...

Introduction De nos jours, il n'existe pas de consensus sur l'influence des supports externes de cheville sur le système neuromusculaire. Les nombreuses études qui se sont intéressées à l'effet de ces supports sur l'acuité proprioceptive font état de résultats controversés. Cette hétérogénéité pourrait trouver une explication dans l'existence de pr...

Introduction Dans le domaine de la réathlétisation ou celui de la réadaptation, l'évaluation de la fonction de contrôle neuromusculaire consiste à apprécier la performance de la boucle sensori-motrice. A cet effet et du fait de la non-intentionnalité des processus de contrôle de maintien statique, les tâches de maintien dynamique ont été privilégié...

Les lésions ligamentaires de la cheville, réputées banales, sont néanmoins parmi les plus fréquentes en traumatologie des membres inférieurs. Cette monographie rassemble de façon exhaustive toutes les données médicales ainsi que les méthodes diagnostiques et thérapeutiques existant sur la cheville instable. Les premiers chapitres présentent les con...

Capsulo-ligamentous damages caused by traumatic inversion during lateral ankle sprains frequently cause Chronic ankle Instability (CAI). CAI is the consequence of passive (mechanical origin) and/or active (functional origin) articular stabilization mechanisms. The detection of patients affected by functional CAI, with objective parameters, is cruc...

Replacing open surgery in several surgical domains, laparoscopic procedures are responsible for additional solicitations to the surgeons. The shape and length of the instruments lead to non-ergonomic postures. Regions mainly affected are neck, shoulders and distal parts of the upper limbs. EMG activities are used to evaluate the benefit of using a...

introduction Le concept 3C constitue une méthode de recentrage dynamique de la tête humérale en chaîne cinétique fermée permettant de lutter contre les mécanismes d’instauration du conflit sous-acromial. Cette étude a pour objectif d’évaluer la pertinence du concept 3C dans le processus de rééquilibration des balances d’activité musculaire en charg...

To investigate the effects of focal muscle fatigue induced by electromyostimulation (EMS) on Anticipatory Postural Adjustments (APAs) during arm flexions performed at maximal velocity.Methods Fifteen healthy subjects performed self-paced arm flexions at maximal velocity before and after the completion of fatiguing electromyostimulation programs inv...

Introduction: L’inclusion d’exercices proprioceptifs dans les programmes de rééducation des entorses latérales de cheville repose sur une idée simple émise par Freeman dès 1965. Il est supposé que la déstabilisation du support augmente l’utilisation des signaux afférents musculaires en provenance de la cheville offrant une in fine meilleure stabili...

Liens d'intérêts : Romain Terrier et Pascal Toschi sont membres de la société CEVRES Santé qui développe le dispositif MyoluxTM utilisé dans cette étude. Nicolas Forestier et Normand Teasdale n'ont aucun lien d'intérêt.

Classiquement, la restauration de la stabilité fonctionnelle d'une articulation repose des exercices de reprogrammation neuro-musculaire ou proprioceptifs pour lesquels les patients sont placés sur des plans instables multidirectionnels qu'ils doivent apprendre progressivement à maîtriser. Conformément aux travaux de Freeman (1965), l'altération d'...

When performing self-paced movements in a fatigued state, internal models can predict the mechanical effects of muscle fatigue. Yet, is it unclear if this is still true when movements are submitted to additional constraints. The purpose of the present study was to investigate the Central Nervous System's (CNS) capacity to integrate fatigue signals...

Objective: The purpose of this study was to test the effect of various unstable support surfaces on the relevance of muscular proprioceptive signals originating from the ankle joint. Design: Ten healthy subjects were instructed to stand as still as possible on a force plate during 40 secs on three different surfaces: (1) stable, (2) unstable-uns...

Muscular fatigue effects have been shown to be compensated by the implementation of adaptive compensatory neuromuscular strategies, resulting in modifications of the initial motion coordination. However, no studies have focused on the efficiency of the feedforward motor commands when muscular fatigue occurs for the first time during a particular mo...

Introduction: Différentes études ont permis de mettre en évidence que la faiblesse des muscles éverseurs représente un facteur majeur conditionnant l’instabilité chronique de cheville. Dans le cadre de protocoles de recherche, la force des éverseurs de cheville est testée au moyen d’évaluations isocinétiques. Cette méthodologie est cependant trop c...

Aim.– The aim was the study of the value of active global (AG) and passive gleno-humeral (PGH) range of motion (ROM) for diagnosing adhesive capsulitis of the shoulder. Patients and methods.– Candidats to arthrodistension for adhesive capsulitis of the shoulder were included. Inclusion criteria were: limitation of AG (abduction or flexion < 180 •)...

Previous studies have proposed that evertor muscle weakness represents an important factor affecting chronic ankle instability. For research purposes, ankle evertor strength is assessed by means of isokinetic evaluations. However, this methodology is constraining for daily clinical use. The present study proposes to assess ankle evertor muscle weak...

Ankle sprain is the most frequent locomotor system pathology, especially in athletic subjects. The present study describes management in a population of 240 young athletes. Results showed that 52% of subjects had sprained their ankle at least once, and that only 57% of these had undergone rehabilitation. Recurrence was equally frequent, regardless...

Le contrôle moteur et la protection articulaire de la cheville 5-Optimisation de la reprogrammation neuro-musculaire : les stratégies de délestage KS n°537 -novembre 2012 71 FOCUS Présentation de la rubrique: cette rubrique bimensuelle en 5 parties consiste à présenter l'évolution des connaissances scientii ques relatives aux mécanismes traumatique...

Le contrôle moteur et la protection articulaire de la cheville 4-Optimisation de la reprogrammation neuro-musculaire : la pro-activation des fi bulaires KS n°535 -septembre 2012 55 FOCUS Présentation de la rubrique: cette rubrique bimensuelle en 5 parties consiste à présenter l'évolution des connaissances scientii ques relatives aux mécanismes trau...

KS n°534 -juillet 2012 53 FOCUS Présentation de la rubrique: cette rubrique bimensuelle en 5 parties consiste à présenter l'évolution des connaissances scientii ques relatives aux mécanismes traumatiques, ainsi qu'aux stratégies de protection de la cheville. Ces informations permettent aux praticiens de déterminer les critères nécessaires à une réé...

Les stratégies de prise en charge des entorses externes de cheville, pathologie la plus courante de l’appareil locomoteur associée à d’importantes répercussions sociétales et économiques, se sont avérées peu efficaces pour prévenir les récidives pouvant atteindre 73 % d’après la littérature. Un chausson biomécanique, équipé d’un articulateur reprod...

The parameters dictating the temporal hand-head coordination during visually corrected movements remain elusive. Here we examine the effects of the nature (discrete vs reciprocal) and the difficulty (ID of 4.7, 5.7 and 6.7 bits) of the task on the temporal hand-head coordination during a Fitts' like paradigm. Subjects aimed at a single target (disc...

Le contrôle moteur et la protection articulaire de la cheville 2-Contrôle moteur de la cheville : optimisation du renforcement des muscles fi bulaires KS n°532 -mai 2012 53 FOCUS Présentation de la rubrique: cette rubrique bimensuelle en 5 parties consiste à présenter l'évolution des connaissances scientii ques relatives aux mécanismes traumatiques...

L'entorse latérale de cheville est la lésion la plus courante de l'appareil locomoteur, et ce particulièrement chez les sportifs. La prise en charge consiste, dans un premier temps, à optimiser la cicatrisation ligamentaire en immobilisant la cheville. Néanmoins, au sortir de l'immobilisation, des déficits fonctionnels persistent et il convient de...

KS n°530 -mars 2012 57 FOCUS Cette rubrique bimensuelle en 5 parties consiste à présenter l'évolution des connaissances scientii ques relatives aux mécanismes traumatiques ainsi qu'aux stratégies de protection de la cheville. Ces informations permettent aux praticiens de déterminer les critères nécessaires à une rééducation ee cace de manière à cho...

La stratégie de protection active de la cheville par pro-activation des muscles fibulaires est bien connu dans la prise en charge rééducative de l’entorse. Néanmoins, lorsque la cheville est soudainement déstabilisée en inversion lors de la locomotion, il est possible dans certains cas d’éviter la lésion. Le but de cette étude est de comprendre com...

Ankle sprain is the most common locomotor injury, particularly in sports. Moreover, despite rehabilitation programs, recurrence rates remain very high and can reach 73% in some sports as basket-ball. Such findings mean that all the actors implicated in the management of this pathology have to work together. A more coordinated reflexion is necessa...

arrière pied, interface directe entre le sol et l'homme en locomotion, est une structure particulièrement instable puisqu'il n'existe aucune insertion tendineuse sur le talus (anciennement astragale, cf. figure 1). Cette instabilité est conditionnée par la configuration de l'articulation entre le talus et le calcaneus (anciennement calcacéum), l'os...

Fatigue of lower limb presents various impacts on postural control. The purpose of this study was to explore the effects of a unilateral lower-limb muscle fatigue on undisturbed stance. Nine healthy men performed until exhaustion a fatiguing exercise of the limb extensor muscles of one leg (exercised leg). Just before and after the fatiguing exerci...

Rapid discrete goal-directed movements are characterized by a well known coordination pattern between the gaze and the hand displacements. The gaze always starts prior to the hand movement and reaches the target before hand velocity peak. Surprisingly, the effect of the target size on the temporal gaze-hand coordination has not been directly invest...

The study investigated the effects of an unilateral ankle muscle fatigue onto independent postural control parameters including the trajectories of the estimated resultant CoP (CoPres) and his components: the centre of gravity (CG) and CoP-CG trajectories. Nine healthy men realized series of 10 toe-lift immediately followed by 10 knee flexions unti...

Muscular fatigue is known to impair motor performance and to catalyse the development of upper limb musculoskeletal disorders. In order to delay the deleterious effects of muscular fatigue, the central nervous system (CNS) employs compensatory strategies. The cognitive cost of such compensatory strategies was assessed in 10 male subjects who altern...

Recent experiments have shown that the vestibular channel of balance control differs fundamentally from the visual channel. Whereas the response to a visual perturbation can be suppressed if the subject has awareness that an upcoming disturbance is likely to be caused by an external agent rather than by self-motion, a similar assumption cannot be m...

To investigate the capacity of the central nervous system to integrate and differentiate two different muscular fatigue states, the present study examines the changes on multi-joint movement organization following muscular fatigue of elbow extensor muscles (triceps brachii) induced by voluntary versus electrically induced contractions. Twenty right...

To investigate the strategies developed by the central nervous system to compensate for fatigue in muscles, we studied the changes in the relative mechanical contribution of the joint torques in a multi-joint movement following an isometric exhaustion test. Eighteen male subjects performed throws, moving the arm in the horizontal plane, before and...

The main objective of this study was to examine whether static and dynamic signals from a non-fatigued reference ankle can differently improve the movement accuracy of a fatigued ankle. To address this question, subjects performed an ankle-matching task in a control condition and in a condition of local fatigue induced in the right tibialis anterio...

Introduction. – The aim of this study was to analyse the evolution of neuromuscular fatigue in vastus lateralis and gastrocnemius medialis muscles during all-out cycling test at 100% maximal aerobic power.Fact synthesis. – Mean EMG increased from the beginning of the test and then decreased after have attained its maximum for all subjects and for b...

Chronic Ankle Instability sprain causes are unclear and many factors or mechanisms may contribute to recurrence of this injury. The aim of the study was to investigate how an ankle destabilization device affects the EMG patterns of the ankle muscles during ankle stabilization against inversion. The left foot was equipped with a mechanical device mo...

The purpose of the present experiment was to investigate whether the calf muscle fatigue affects postural sway in bipedal stance and requires additional attentional demands. Nine healthy university students had to respond as rapidly as possible to an unpredictable auditory stimulus while maintaining stable seated and upright postures with their eye...

Separate studies have demonstrated that vibration and fatigue of ankle muscles alter postural control. The purpose of the present experiment was to investigate the effect of ankle muscle vibration on the regulation of postural sway in bipedal stance following ankle muscle fatigue. Center of foot pressure displacements were recorded using a force pl...

The purpose of this study was to investigate how an isometric exhaustion test affects the position sense at the ankle using an active matching task. Eight male subjects with a mean age 24.6 yr participated in the study. Subjects' ability to match the right ankle with the position of the left reference ankle position-determined using signed and abso...