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Gait is the main mean of movement for Man, therefore an abnormality or deficiency related to it can be disabling. This deficiency is generally caused by a muscular dysfunction or some neurological ...

Context: Fatigue-induced alterations in foot mechanics may lead to structural overload and injury. Objectives: To investigate how a high-intensity running exercise to exhaustion modifies ankle plantar-flexor and dorsiflexor strength and fatigability, as well as plantar-pressure distribution in adolescent runners. Design: Controlled laboratory study. Setting: Academy research laboratory. Patients or Other Participants: Eleven male adolescent distance runners (age = 16.9 ± 2.0 years, height = 170.6 ± 10.9 cm, mass = 54.6 ± 8.6 kg) were tested. Intervention(s): All participants performed an exhausting run on a treadmill. An isokinetic plantar-flexor and dorsiflexor maximal-strength test and a fatigue test were performed before and after the exhausting run. Plantar-pressure distribution was assessed at the beginning and end of the exhausting run. Main Outcome Measure(s): We recorded plantar-flexor and dorsiflexor peak torques and calculated the fatigue index. Plantar-pressure measurements were recorded 1 minute after the start of the run and before exhaustion. Plantar variables (ie, mean area, contact time, mean pressure, relative load) were determined for 9 selected regions. Results: Isokinetic peak torques were similar before and after the run in both muscle groups, whereas the fatigue index increased in plantar flexion (28.1%; P = .01) but not in dorsiflexion. For the whole foot, mean pressure decreased from 1 minute to the end (−3.4%; P = .003); however, mean area (9.5%; P = .005) and relative load (7.2%; P = .009) increased under the medial midfoot, and contact time increased under the central forefoot (8.3%; P = .01) and the lesser toes (8.9%; P = .008). Conclusions: Fatigue resistance in the plantar flexors declined after a high-intensity running bout performed by adolescent male distance runners. This phenomenon was associated with increased loading under the medial arch in the fatigued state but without any excessive pronation.

An emerging and dynamic Industrial and manufacturing sector is significant for revenue generation in any country; specifically in the developing countries its importance is vital. Private sector manufacturing constitutes the core of the financial sectors in Asian countries in specific and in the world as a whole. Private sector industries in south Asian countries are facing various challenges such as global and technological revelation, competition, and service diversification. In this challenging environment, stress has become a part of organizational system. The modern corporate sector has adopted different methods of stress management and there focus is chronic stress. Private sector organizations have many ongoing situations that can cause of chronic stress and every employee cannot handle with such kind of pressure. This study explores a correlation among various influencing factors and associated behaviours. The paper fleshes out the contributory factors of stress in an analytical way to analyse the causes. The paper finally suggests a comparative study on organization stress based on actual case studies from the manufacturing sector. This research tries to figure out a way forward in order to manage all stresses positively and a mechanism to handle individual and organizational level stresses to in an organization and eventually in a society.

Background The use of surface electromyography (sEMG) to evaluate muscle activation when executing whole body vibration exercises (WBVE) in studies provide neuromuscular findings, in healthy and diseased populations. Objectives Perform a systematic review of the effects of WBVE by sEMG of lower limbs in non-healthy populations. Methods The search using the defined keywords was performed in PubMed, PEDRo and EMBASE databases by three independent researchers. Applying the PRISMA statement several studies were selected according to eligibility criteria and organized for the review. Full papers were included if they described effects of WBVE for the treatment of illnesses, evaluated by sEMG of lower limbs independently on the year of the publication; in comparison or associated with other treatment and evaluation techniques. Results Seven publications were selected; two in spinal cord injury patients, one in Friedreich's ataxia patients, three in stroke patients and one study in breast cancer survivors. Reported effects of WBV in were muscle activation by sEMG and also on strength, blood flow and exercise resistance; even in paretic limbs. Conclusion By the use of sEMG it was verified that WBVE elicits muscle activation in diseased population. These results may lead to the definition of exercise protocols to maintain or increase muscular activation. However, due to the heterogeneity of methods among studies, there is currently no consensus on the sEMG signal processing. These strategies might also induce effects on muscle strength, balance and flexibility in these and other illnesses.

The pressure ulcers are injuries caused by a constant pressure and without slackening, which damage skin and the subcutaneous flesh, because of the lack of mobility and blood circulation. The injur...

Introduction Although fibromyalgia syndrome (SFM) affects 2–4 percent of adults, research has not identified a preferred therapeutic option for patients worldwide yet. Based on recent findings, it can be expected that whole body cryotherapy can improve health-reported quality of life by alleviating the symptoms of musculoskeletal pain and fatigue. Objective Our aim was to determine whether whole body cryotherapy only can result in improved perceived health and quality of life in fibromyalgia patients. Methods 24 patients with fibromyalgia diagnosis were randomized into 2 groups (n = 11 in the whole body cryotherapy group, n = 13 in the control group). In the whole body cryotherapy group, 10 sessions of whole body cryotherapy were performed (in addition to usual care) in a standard cryotherapy room over a duration of 8 days. Subjects in the control group did not change anything in their everyday activities. Quality of life was assessed just before and one month after treatment. Results Compared with the control group, patients in the whole body cryotherapy group reported significantly improved for health-reported quality of life. These effects lasted for at least one month following intervention. Conclusion Based on these findings, whole body cryotherapy can be recommended as an effective clinically adjuvant approach in the improvement of health-related quality of life in fibromyalgia patients.

Health and individual’s wellbeing is influenced by a range of factors such as social, cultural, economic, psychological and environmental. For instance, people spend approximately 8 h per day at work, where they are exposed to multiple stressors that have a negative impact on their health. This increases the risk of disease, especially for those who present low levels of physical activity per day. The objective of this study is to assess the impact of new generation of advanced ‘smart’ material on body balance at work. Studying the body upright position and balancing by utilization of technological mats helps professionals in their daily life through decreasing muscular problems, especially fatigue. This is due to the increased frequency and repetition of movements that are performed by professionals over extended periods of time. Another objective of this study is to validate model prototypes that improve ergonomics at work, as well as optimize users’ comfort; a new anti-fatigue mats by Notrax®. A total of 25 professionals from different age groups participated in the study which took place for a period of six months. A dysfunction in balance was observed in professionals who didn’t use mats. Dysfunction in balance can cause pathologies, strain and fatigue therefore disorders due repetitiveness. Additionally, a significant increase of balance was observed for those who used the mats in comparison of those without mats (p < 0.05). Significant variations were also observed between the different mats and their specifications (p < 0.05). Utilization of mats helps professionals on their daily life by decreasing joint stresses and optimizing body balance.

The purpose of this study is to develop a numerical methodology based on real data from wind tunnel experiments to investigate the effect of the ski jumper's posture and speed on aerodynamic forces in a wide range of angles of attack. To improve our knowledge of the aerodynamic behavior of the ski jumper and his equipment during the early flight phase of the ski jump, we applied CFD methodology to evaluate the influence of angle of attack (α=14°, 21.5°, 29°, 36.5° and 44°) and speed (u=23, 26 and 29m/s) on aerodynamic forces in the situation of stable attitude of the ski jumper's body and skis. The standard k-ω turbulence model was used to investigate both the influence of the ski jumper's posture and speed on aerodynamic performance during the early flight phase. Numerical results show that the ski jumper's speed has very little impact on the lift and drag coefficients. Conversely, the lift and drag forces acting on the ski jumper's body during the early flight phase of the jump are strongly influenced by the variations of the angle of attack. The present results suggest that the greater the ski jumper's angle of inclination, with respect to the relative flow, the greater the pressure difference between the lower and upper parts of the skier. Further studies will focus on the dependency of the parameters with both the angle of attack α and the body-ski angle β as control variables. It will be possible to test and optimize different ski jumping styles in different ski jumping hills and investigate different environmental conditions such as temperature, altitude or crosswinds.

The standardization effort in vibration’s field has unfolded the interests of industries. This research aimed at better understanding of the impact of vibration on human body. In the past years, healthcare centers and manufacturers started to equip the workplace with Anti-fatigue Mats (AFM) for the improvement of the working conditions and quality at work. This study analyzed the impact of AFM on the reduction of vibrations transmitted during the weekly activity of manufacturing workers. Seven AFM marketed by Notrax Premium Superior Manufacturing Group were tested. The laser vibrometry technique was used in order to measure vibratory displacements at various points. Under the effect of the vibrations, AFM behaved differently according to their structure and geometries. In comparison, the values obtained showed that AFM absorbed the vibration. It permitted to decrease the risks of ligamentous, or articular pathologies, which can affect employees at work. Taking into account, different results obtained showing that AFM could be used effectively in different areas of workplace, such as in medical or manufacturing settings, in order to improve working conditions.

The Manual Wheelchair (MW) is an important device which provides technical assistance to people affected by mobility impairments. This mode of displacement is neither natural nor easy and the environments, whether natural or built, can present various obstacles, which will restrict mobility and the social participation of MW users. Users complete autonomy depends on their capacity to cope with the many obstacles of their daily life, such as pavements or unleveled grounds. Ever since its invention the MW as an economical mobility solution, it has gone through many improvements, yet its technological innovation slowed down during the recent years. In this study, we present a novel design of MW. Its conception includes innovative kinematics with genuine lifting and folding systems. A lever system mounted on hubless-wheels is dedicated to the propulsion mechanism. The objective of this new concept is the optimization of MW mechanism to be more user friendly and to take into account the ergonomics considerations in an attempt to improve the user’s daily life.

International audience; Because it induces a state of reduced awareness and deep relaxation, hypnosis is thought to be efficient at relieving stress and anxiety. This study examined whether hypnosis may alter the pattern and time evolution of maternal and fetal stress. Here we report a 23-yrs-old primigravida woman at 31-weeks' gestation who underwent daily sessions of hypnosis during one week. An A (baseline)-B (intervention) - A' (return to baseline) design was used. Each study phase lasted one week. The State Anxiety Inventory (SAI) was completed daily. Uterine contractions as well as maternal and fetal heart rate were recorded over 24-h periods in each of the study phase. Uterine contractions and maternal systolic blood pressure showed clear reductions during the hypnosis phase. In addition, a statistically significant declining trend in anxiety scores was observed during the hypnosis phase, and anxiety re-increased in the return-to-baseline phase (p

Vibrations in cycling produced by road irregularities could cause health problems and affect the cyclist’s comfort and performance. Therefore researchers and manufacturers focus their efforts to reduce the vibrations., Las vibraciones en el ciclismo producidas por las irregularidades de la carretera podrían causar problemas de salud y afectar a la comodidad y el rendimiento del ciclista. Por ello, los investigadores y los fabricantes centran sus esfuerzos en reducir las vibraciones., 1. GRESPI, Moulin de la Housse, Université de Reims Champagne Ardenne, Reims, France 2. IN’BO, ZA Les Bouleaux, Les Voivres, France 3. Escuela Colombiana de Ingeniería Julio Garavito, Bogotá D.C., Colombia 4. Montclair State University, Upper Montclair, New Jersey, USA 5. EPF, 3 bis rue Lakanal, Sceaux, France 6. Arts et Métiers ParisTech, MSMP / EA7350, Châlons-en-Champagne, France

Acta of Bioengineering and Biomechanics; 02/2017; ISSN 1509-409X

Inadequate safety shoe wearing is thought to be responsible of many musculoskeletal disorders. A new concept of unstable footwear is proposed to reduce mechanical stresses during work. Major expectations argue for a better ankle dynamic behavior leading to an increased muscular activity. The aim of this study was to evaluate the variation of stance characteristics while walking on level ground as a function of the models of safety shoes. Twenty healthy males (aged 23.6 ± 7) were asked to make six gait cycles on a walking track while barefoot, shod with low cost safety footwear, high cost one, and equipped by Masa? Barefoot Technology shoes (the most unstable footwear). Stance phases (heel strike, flat foot and toe-off) have been normalized as percentages of the maximum value of ground reaction force recorded during each step. The highest significant percentages have been observed in Masa? Barefoot Technology shoes condition and only during heel strike (8% to 10.1% higher) and toe-off (10% to 11.3% higher). In contrast, the temporal durations of the three stance phases were not significantly different between the four conditions. The convexity of safety shoe induces less stability increasing the adaptation of the muscle activity of the wearer at heel-strike and toe-off in order to regain stable gait pattern.

Introduction/Background Fibromyalgia is a chronic disease that causes muscle pain and fatigue. Our objective was to determine whether Whole Body Cryotherapy (WBC) can result in improved functional status and pain in fibromyalgia patients. It was hypothesized that positive effects will be realized due to the cold-induced modulation of the inflammation-immune axis. Material and method This present study is a randomized controlled trial with one between-subject factor (WBC group vs. Control group) and one within-subject factor (measurement point with 4 levels: pre-study, J8, 2 weeks later, 1 month later). Several parameters assessing pain intensity and functional status were measured repeatedly. In the WBC group, 10 cryostimulation sessions were performed (in addition to usual care) in a two-stage cryogenic chamber over a duration of 8 days. Duration of each cold exposure session was set to 3 minutes at a temperature of −110 °C. Subjects in the control group did not receive this intervention, and changed nothing in their everyday activities. Our primary study outcome measurement was recalled pain intensity over the last 7 days. Results A convenience sample of 28 patients (Mage = 52.4 ± 10.3 yrs old; 75% females) with fibromyalgia diagnosis were randomized (WBC, control). In pretest, the usual pain scores were respectively 7.50 ± 1.81 for the experimental group (WBC) and 5.92 ± 1.75 for the control group. It was a usual pain reduction at j8, 2 weeks and 1 month with respectively 4.88 ± 2.98 (P Conclusion Patients with fibromyalgia were improved for pain and functional mobility after 10 whole-body cryostimulation (WBC) sessions compared the outcomes in the control group.

Metabolic syndrome (MetS) is an undesirable clinical condition with physiological, biochemical, clinical, and metabolic factors that contribute to increased cardiovascular risks (CR). A poor sleep quality might be found in obese and MetS individuals. Whole-body vibration (WBV) exercise has been used on the management of MetS individuals. This clinical trial investigated the effect of WBV exercise on parameters related to the sleep quality in MetS individuals. After randomization, nine individuals (seven women and two men) were exposed to a fixed frequency (FF) and ten individuals (eight women and two men) were exposed to a variable frequency (VF). Both groups performed the protocol twice a week, for 6 weeks. All of the evaluations were performed before the first and after the last sessions. Anthropometric and cardiovascular parameters were measured before and after the 6-week intervention. Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Berlin Questionnaire were also used to evaluate the quality of the sleep. A significant (p ≤ 0.05) reduction of the waist circumference in the VFG and an increase of the heart rate were found in the FFG and VFG group. The score of the PSQI of the both groups decreased significantly (p = 0.01). The score of the ESS decreased (p = 0.04) only in the VF group. The scores of the Berlin Questionnaire were not altered in both groups. In conclusion, WBV intervention was capable in interfering with physiological mechanisms with effects on the WC and HR, leading to the improvement of the quality of sleep in MetS individuals. WBV exercise might be an important clinical intervention to the management of some factors associated with poor quality of sleep (FFG and VFG) and in the daytime sleepiness in MetS individuals with variable frequencies (5–16 Hz) (VFG).

This study evaluated the effects of 6 weeks of whole-body vibration (WBV) exercise on flexibility and the rating of perceived exertion (RPE) in metabolic syndrome (MetS) individuals using 2 biomechanical conditions (fixed frequency [FF] and variable frequency [VF]). Nineteen MetS individuals were randomly allocated in FF-WBV (n = 9, 7 women and 2 men) and VF-WBV (n = 10, 8 women and 2 men) groups. Anterior trunk flexion (ATF) and RPE were determined before and after each session. The acute cumulative exposure effects were analyzed. The FF-WBV group was exposed to 5 Hz on a side alternating vibrating platform (SAVP), exposed to 10 and 50 seconds with the SAVP turned off. The VF-WBV group individuals were intermittently exposed (1 minute WBV exercise/1 minute rest) to 5 to 16 Hz, increased by 1 Hz per session and the peak-to-peak displacement (PPD) were 2.5, 5.0, and 7.5 mm. Regarding to ATF, significant improvements ( P < .05) were observed in the in the acute (VF group) and cumulative intervention (FF and VF-WBV groups). The RPE significantly ( P < .05) improved only in VF-WBV (cumulative intervention). In conclusion, WBV exercise improved the flexibility and decreased the RPE in MetS individuals. These findings suggest that WBV exercise can be incorporated into physical activities for MetS individuals.

After a vestibular deficit some patients may be affected by chronical postural instability. The aim of this study was to identify the emotional and cognitive factors of these symptomatic patients. In particular, the double cognitive task and the anxiety disorder were identified by our patients. Through a retrospective study, 14 patients (65.4 ± 18 years) participated in the experiment.The experimentation consists in the study of the standing position of our patients through the aggregate of the trajectories of the center of pressure (COP) using a force plate device. With the aim of isolating the emotional and cognitive influence, this experimentation was defined in two conditions. In the first one, the patients were asked to maintain their balance without additional tasks. In the second one, the patients were submitted to an additional cognitive arithmetic task. The stabilogram surface, length (the forward and backward displacement distance during deviations in COP), lateral and the antero-posterior deviations were assessed.Our results showed an increase of postural instability of patients affected by chronical vestibular disorders when submitted to the double task. The patients submitted to the cognitive task present a larger surface of activity in comparison with the free-task one (Wilcoxon test p-value equals p = 0.0453). In addition, their displacements inside this area are more important (p = 0.0338). The COP of all our patients deviated forward in the presence of the double task.The increase in instability during the double cognitive task could be explained by an additional stress caused by the desire to make a success of the cognitive task.

The objective of this article is to perform a numerical modeling on the flow dynamics around a competitive female swimmer during the underwater swimming phase for a velocity of 2.2 m/s corresponding to national swimming levels. Flow around the swimmer is assumed turbulent and simulated with a computational fluid dynamics method based on a volume control approach. The 3D numerical simulations have been carried out with the code ANSYS FLUENT and are presented using the standard k-ω turbulence model for a Reynolds number of 6.4 × 106. To validate the streamline patterns produced by the simulation, experiments were performed in the swimming pools of the National Institute of Sports and Physical Education in Paris (INSEP) by using the tufts method.

Resume Introduction Le disque articulaire situe au cœur meme de l’articulation, de par sa biodynamique particuliere, peut avoir des consequences sur l’ensemble des elements de l’appareil manducateur. Soumis a des contraintes engendrees par les muscles masticateurs, ce disque en absorbe une partie, en redistribue et se deforme. Materiels et methodes Des coupes scanner et des images IRM d’un individu ont ete necessaires pour creer un modele anatomique en elements finis de cette articulation. Les forces appliquees au modele de l’articulation de l’individu sont issues d’une decomposition vectorielle des forces musculaires maximales developpees par ce meme individu. Cette force resultante dans cette etude est soumise a differentes frequences proches de celle de la mastication. Resultats La force de reaction au niveau de la cavite glenoide peut atteindre 1035 N en fonction de la frequence d’indentation. Generalement, dans les differents exercices, les zones de contraintes maximales se situent au niveau de la portion laterale du disque ainsi que sur son bourrelet posterieur. Elles peuvent atteindre 13,2 MPa au bout d’un exercice de 32 s a la frequence de 0,5 hz. Discussion Meme si la loi de comportement necessite d’etre amelioree, la resilience articulaire est mise en evidence dans cette etude. Les zones ou les contraintes sont maximales sont equivalentes en fonction des differents exercices imposes du fait de l’anatomie des pieces et de l’axe des forces appliquees. Cette etude offre un terrain de reflexion vis-a-vis des pathologies articulaires ainsi qu’une ouverture vers d’autres travaux visant a completer ce travail.

Background and aim Individuals with metabolic syndrome (MetS) might present low muscle performance resulting in a decrease of the functional capacity interfering in the gait time. Whole body vibration exercise (WBVe) has been considered in the management of MetS individuals promoting a better functional performance. The aim of this study was to evaluate the effects of WBVe on the gait time of the MetS individuals. Methods CAAE 19826413.8.0000.5259. UTN: U1111-1181-1177; Brazilian Registry of Clinical Trials- ReBEC RBR - 2bghmh. A pseudo randomized controlled trial study with thirty-nine individuals with MetS (according International Diabetes Federation) was performed. The side-to-side alternating oscillating/vibratory platform was used. The individuals were allocated in WBVe group (WBVeG = 22) and in control group (CG = 17). The WBVeG was in squat static position for 1 minute of intervention and 1 minute of rest in 3 different peak-to-peak displacements (2.5, 5.0 and 7.5 mm) 3 times. In the first session was used 5 Hz and increasing 1 Hz in each session up to 14 Hz in the tenth session. In the CG was used the same position and time but the platform was turned off. Before the first and after the tenth session were collected the data about the gait time of 3 meters (in seconds). The statistical analysis was performed using the Graph Pad Prism 5.01 Program (P≤0.05). Results The gait time (Mean ± SD) showed a significant difference intergroups. Conclusion WBVe is a modality of physical activity that can improve the functional capacity of the MetS individuals, at least, considering the time of the gait.

The aim of this work is to specify which model of turbulence is the most adapted in order to predict the drag forces that a swimmer encounters during his movement in the fluid environment. For this, a Computational Fluid Dynamics (CFD) analysis has been undertaken with a commercial CFD code (Fluent ® ). The problem was modelled as 3D and in steady hydrodynamic state. The 3D geometry of the swimmer was created by means of a complete laser scanning of the swimmer’s body contour. Two turbulence models were tested, namely the standard k – e model with a specific treatment of the fluid flow area near the swimmer’s body contour, and the standard k – ω model. The comparison of numerical results with experimental measurements of drag forces shows that the standard k–ω model accurately predicts the drag forces while the standard k – e model underestimates their values. The standard k – ω model also enabled to capture the vortex structures developing at the swimmer’s back and buttocks in underwater swimming; the same vortices had been visualized by flow visualization experiments carried out at the INSEP (National Institute for Sport and Physical Education in Paris) with the French national swimming team.

The corset support is a device classified as orthosis. It compensates a functional deficiency with means of protection, recovery, correction, maintenance, and support or contention. There are two types of orthosis 1) rest orthosis and 2) corrective orthosis. Rest orthosis maintains joints in a defined position to avoid deformities or to relieve a pain at joints. Corrective orthosis adjusts joint deformity either passively or actively. Corset is used in various pathological use, thoracic-lumbar fracture, scoliosis, Scheuermann’s disease or spinal dystrophy. The purpose of this study was 1) to determine the immediate impact of wearing a semi-rigid thoracolumbar corset, the Lombax® Dorso on gait kinematics and 2) spatiotemporal parameters in 6 adults. These parameters were recorded using the optoelectronic system Vicon® on treadmill gait subjects with and without corset for the comparison. The results showed that wearing a corset significantly decrease the rotation amplitudes of the scapular and pelvic girdles (p

Dizziness and balance disorders are frequent complaints in the general population. Vestibular rehabilitation exercises have been shown to be efficient in controlled studies, provided that a precise, individual diagnosis has previously been made. Depending on the pathology, a subject with a peripheral vestibular pathology can benefit from manoeuvres aiming at dislodging or repositioning otoliths, from non-specific muscles strengthening techniques, from techniques for vestibular-ocular or vestibular-cervical stabilisation of gaze, or from physical exercises aimed at strengthening proprioceptive afferents, inhibiting a sensory predominance, or improving spatial orientation and navigation. These analytical exercises should then be implemented in an ecological context in order to favour transfer to daily-living activities. These physical exercises can enable the development of compensation strategies following vestibular damage (habituation, adaptation and substitution).

At the interface with an implant, bone tends to change its properties, affecting the acceptance of the implant. The preferred orientation of hydroxyapatite Ca10(PO4)6(OH)2 (HAp) crystallites at the bone–implant interface has been measured with the D20 neutron 2-axis diffractometer at the Institut Max von Laue-Paul Langevin, Grenoble. The implant has two faces, one coated with plasma-sprayed HAp.

To build a questionnaire to assess health-related quality of life (HRQL) in patients suffering from slowly progressive neuromuscular disease (NMD) using item response theory (IRT). A pool of 64 items and a validated questionnaire (WHOQOL-BREF) were administered to 159 patients recruited in eight NMD referral centers. Exploratory statistical analysis included methods derived from both IRT and classical test theory. We constructed a questionnaire named QoL–NMD which is composed of two general items and 24 items classified in three domains: (1) “Impact of Physical Symptoms,” (2) “Self-perception” and (3) “Activities and Social Participation.” Each domain has good psychometric properties (Cronbach’s alpha > 0.77, test–retest ICC > 0.81, Loevinger’s H > 0.41) and meets IRT assumptions. Comparison with the WHOQOL-BREF enabled assessing similarities and discrepancies with a generic questionnaire. This study enabled the development of a new HRQL questionnaire specifically designed for slowly progressive NMD patients. The QoL–NMD is short enough to be used in clinical practice (26 items). The next steps will be to validate QoL–NMD by re-assessing psychometrics in an independent sample of patients and calibrate the IRT scoring system.

By means of MSC Adams- BRG LifeMOD software, a three dimensional lower extremity model has been developed in this study. This model take into account 16 muscles, 4 ligaments, 2 tendons in order to quantify forces and contacts (patello-femoral and tibio-femoral) during muscular training movement (e.g. a squat) with various raised loads (0, 20 and 30 kg). The first results showed the importance of the relationships between muscle activations (e.g. Quadriceps, Hamstrings) and ligament forces (e.g. Anterior and Posterior Cruciate Ligaments).

Resume Objectif. – L'objectif de notre etude est de tester l'influence de la raideur des membres inferieurs sur la performance lors de sauts de contre-haut a travers des instructions donnees sur la flexion du genou. Methode. – Douze basketteurs doivent sauter selon trois types d'instructions : 1) saute haut avec une flexion de genoux au sol aussi grande que possible ; 2) saute le plus haut possible ; 3) saute haut avec une flexion de genoux au sol aussi petite que possible. La cinematique et la cinetique sont enregistrees. Resultats. – Les resultats montrent que la courbe de force de reaction depend plus du type d'instruction que de la hauteur du contre-haut. Le pic concentrique diminue de 6 a 2,9 fois le poids du corps avec la flexion de genou. Sauter avec les genoux plus tendus represente donc une strategie efficace pour augmenter la raideur des membres inferieurs [r = 0,86 ; p Conclusion. – Comme cela etait attendu, la consigne amplitude importante correspondait a une diminution notable de la raideur. Une meme performance peut etre realisee avec differentes valeurs de raideur. La flexion maximale du genou lors de sauts de contre-haut ne modifie pas la performance.

Introduction Dans la litterature, plusieurs etudes se sont interessees a l’analyse cinematique des mouvements du bassin au cours de la marche des personnes amputees (Sjodahl et al., 2003). D’autres etudes ont montre le role essentiel des epaules au cours de la marche (Cappozzo et al., 1982). L’interaction entre le bassin et les epaules semble avoir une importance particuliere. L’objectif de ce travail est d’etudier la cinematique des deplacements des ceintures scapulaire et pelvienne dans le plan sagittal et horizontal au cours de la marche des personnes amputees trans-tibiales. Materiel et methodes Vingt sujets sains (47,35 ± 16,64 ans) et 19 personnes amputees (53 ± 12,08 ans) ont beneficie d’une analyse quantifiee de la marche avec un systeme optoelectronique VICON. Les mouvements des ceintures scapulaire et pelvienne ont ete analyses dans le plan sagittal et horizontal avec un logiciel VICON Workstation. Resultats Dans le plan sagittal, l’amplitude des mouvements des epaules est significativement plus elevee au cours de la marche des personnes amputees (sains : 53,1 ± 16,5° ; amputes : 65,6 ± 22,4°). L’amplitude des mouvements du bassin augmente de 21 % au cours de la marche des personnes amputees par rapport aux sujets sains (p Discussion–conclusion Les personnes amputees presentent des amplitudes de deplacement plus elevees des epaules et du bassin par rapport aux sujets sains (Goujon-Pillet et al., 2008). Le deplacement maximal des epaules dans un sens est suivi par un deplacement maximal du bassin dans le sens contraire. Ceci nous permet de comprendre le role compensatoire des epaules au cours de la marche. Les mouvements des epaules et du bassin devraient etre consideres au cours de la reeducation des personnes amputees.

The validity of an accelerometric system (Myotest©) for assessing vertical jump height, vertical force and power, leg stiffness and reactivity index was examined. 20 healthy males performed 3×"5 hops in place", 3×"1 squat jump" and 3× "1 countermovement jump" during 2 test-retest sessions. The variables were simultaneously assessed using an accelerometer and a force platform at a frequency of 0.5 and 1 kHz, respectively. Both reliability and validity of the accelerometric system were studied. No significant differences between test and retest data were found (p

International audience

International audience; This study deals with recent researches undertaken by the authors in the field of hydrodynamics of human swimming. The aim of this numerical study was to investigate the flow around the entire swimmer's body. The results presented in this article focus on the combination of a 3D computational fluid dynamics code and the use of the k-ω turbulence model, in the range of Reynolds numbers representative of a swimming level varying from national to international competition. Emphasis is placed on the influence of a postural change of the swimmer's head in hydrodynamic performances, which is directly related to the reduction of overall drag. These results confirm and complete those, less accurate, of a preliminary 2D study recently published by the authors and allow the authors to optimise the swimmer's head position in underwater swimming.

The origin of infrared thermography comes in 1800 when William Herschel discovered thermal radiation, the invisible light later called infrared, but only in the mid-sixties infrared thermography became a technique of temperature cartography. He proved that this radiation, called infrared, followed the same law as visible light. Later, this phenomenon was connected with the laws of Planck and Stefan. The first detectors for this type of radiation, based on the principle of the thermocouple and thermopile called, were developed around 1830. In 1970, the first cameras appeared for commercial. The first models were made up of a technology-based pyroelectric tube with an optical IR instead of the classical elements. Today, these concepts have been improved with new technologies in electronics and computing. Infrared acquisition systems can arrive at very high frame rates. The major argument is whether infrared thermography can determine thermal variations to enable sufficient quantitative analyses. The creation of computerized systems using complex statistical data analysis, which ensure high quality results, and the enhancement of thermal sensitivity have increased the development of technology of infrared thermography.

The proposed biodynamic model of the articular disc joint has the ability to affect directly the complete chewing mechanism process and its related muscles defining its kinematics. When subjected to stresses from the mastication muscles, the disc absorbs one part and redistributes the other to become completely distorted. To develop a realistic model of this intricate joint a CT scan and MRI images from a patient were obtained to create sections (layers) and MRI images to create an anatomical joint CAD model, and its corresponding mesh element using a finite element method. The boundary conditions are described by the external forces applied to the joint model through a decomposition of the maximum muscular force developed by the same individual. In this study, the maximum force was operating at frequencies close to the actual chewing frequency measured through a cyclic loading condition. The reaction force at the glenoid fossa was found to be around 1035 N and is directly related to the frequency of indentation. It is also shown that over the years the areas of maximum stresses are located at the lateral portion of the disc and on its posterior rim. These forces can reach 13.2 MPa after a period of 32 seconds (s) at a frequency of 0.5 Hz. An important part of this study is to highlight resilience and the areas where stresses are at their maximum. This study provides a novel approach to improve the understanding of this complex joint, as well as to assess the different pathologies associated with the disc disease that would be difficult to study otherwise.

Summary Introduction On account of its specific biodynamics, the disc joint located at the very heart of the joint can impact every constituent of the manducatory system. The disc is deformed when subjected to stresses exerted by the muscles of mastication which it partly absorbs and partly redistributes. Materials and methods CT-scan slices and MRI images of a subject were made in order to create a finite element anatomical model of the TMJ. The forces applied to the subject's joint model were obtained by performing vector decomposition of the maximum muscle forces produced by this individual. The resultant force in this study was subjected to different frequencies approximating those observed in mastication. Results The reaction force at the glenoid fossa can reach up to 1035 N depending on the frequency of the indentation. Generally, during the different exercises, the areas of maximum stress were located at the lateral portion of the disc and on the posterior band. They reached forces up to 13.2 MPa following a 32 s exercise at a frequency of 0.5 Hz. Discussion Even if the behavior law needs to be improved, joint resiliency was demonstrated in this study. The areas of maximum stress were equivalent in the different exercises on account of the anatomy of the different parts and the axis of the forces applied. This study offers food for thought regarding joint disorders and opens the way for further research to complement the current investigation.

International audience; This paper aimed to study the feasibility of application of infrared thermography to detect osteoarthritis of the knee and to compare the distribution of skin temperature between participants with osteoarthritis and those without pathology. All tests were conducted at LACM (Laboratory of Mechanical Stresses Analysis) and the gymnasium of the University of Reims Champagne Ardennes. IR thermography was performed using an IR camera. Ten participants with knee osteoarthritis and 12 reference healthy participants without OA participated in this study. Questionnaires were also used. The participants with osteoarthritis of the knee were selected on clinical examination and a series of radiographs. The level of pain was recorded by using a simple verbal scale (0-4). Infrared thermography reveals relevant disease by highlighting asymmetrical behavior in thermal color maps of both knees. Moreover, a linear evolution of skin temperature in the knee area versus time has been found whatever the participant group is in the first stage following a given effort. Results clearly show that the temperature can be regarded as a key parameter for evaluating pain. Thermal images of the knee were taken with an infrared camera. The study shows that with the advantage of being noninvasive and easily repeatable, IRT appears to be a useful tool to detect quantifiable patterns of surface temperatures and predict the singular thermal behavior of this pathology. It also seems that this non-intrusive technique enables to detect the early clinical manifestations of knee OA.

International audience

Background Botulinum toxin is commonly used to treat spastic equinus foot. This treatment seems to improve gait in hemiplegic patients when used alone or combined with an ankle-foot orthosis. However, the nature and effects of this improvement have until now rarely been studied. The aim of this study was to quantify the impact of a Botulinum toxin injection in the triceps surae of hemiplegic patients with equinus foot, used either alone or in combination with an ankle-foot orthosis, on the kinematics and dynamics of the paretic lower limb, and to determine the advantage of combining an ankle-foot orthosis with this pharmacological treatment. Methods Patients were assessed using gait analysis to measure spatio-temporal, kinematic and dynamic parameters of the gait cycle before Botulinum toxin injection and then 3 and 6 weeks after injection. Eight chronic hemiplegics following central nervous system lesion were included. Findings Botulinum toxin injection led to an increase in velocity, peak ankle dorsiflexion during stance phase, and peak knee flexion during swing phase. It also resulted in an increased peak plantarflexion moment. Use of ankle-foot orthosis led to a specific increase in peak ankle dorsiflexion during swing phase and also increased peak plantarflexion moment. Interpretation The results indicate that combined Botulinum toxin injection of the triceps surae and wearing an ankle-foot orthosis is more effective than the use of Botulinum toxin only. Use of an ankle-foot orthosis increases ankle dorsiflexion during the swing phase and does not reduce the benefits gained by the use of Botulinum toxin in stance phase.

International audience; The purpose of this study was to determine the swimmers' loss of speed during the underwater gliding motion of a grab start. This study also set out to determine the kinematical variables influencing this loss of speed. Eight French national-level swimmers participated in this study. The swimmers were filmed using 4 mini-DV cameras during the entire underwater phase. Using the DLT technique and the Dempster's anthropometric data, swimmer's movement have been identified. Two principal components analysis (PCA) have been used to study the relations between the kinematical variables influencing the loss of speed. The swimmers reached a velocity between 2.2 and 1.9 m s À1 after their centre of mass covered a distance ranging between 5.63 and 6.01 m from the start wall. For this range of velocity, head position was included between 6.02 and 6.51 m. First PCA show that the kinematical parameters at the immersion (first image at which the swimmers' whole body was under water) are included in the first two components. Second PCA show that the knee, hip and shoulder angles can be included in the same component. The present study identified the optimal instant for initiating underwater leg movements after a grab start. This study also showed that the performance during the underwater gliding motion is determined as much by variables at the immersion as by the swimmer's loss of speed. It also seems that to hold the streamlined position the synergetic action of the knee, the hip and the shoulder is essential.

The aim of this numerical work is to analyze the effect of the position of the swimmer's head on the hydrodynamic performances in swimming. In this initial study, the problem was modeled as 2D and in steady hydrodynamic state. The geometry is generated by the CAD software CATIA and the numerical simulation is carried out by the use of the CFD Fluent code. The standard k-epsilon turbulence model is used with a specific wall law. Three positions of the head were studied, for a range of Reynolds numbers about 10(6). The obtained numerical results revealed that the position of the head had a noticeable effect on the hydrodynamic performances, strongly modifying the wake around the swimmer. The analysis of these results made it possible to propose an optimal position of the head of a swimmer in underwater swimming.

International audience; The main aim of the study is to propose an approach for 3D modeling and simulation of swimmers impulse during a grab start. Four national level swimmers were investigated. For every swimmer, 3D model was generated in BRG.LifeMOD TM on the base of individual morphologic parameters and kinematic data obtained by high speed video camera and passive markers attached at the level of each important articulation. The proposed approach allows predicting swimmer's joint moments for each important articulation during the impulse phase of the grab start and to analyze the segmental coordination for each studied swimmer in order to optimize the performance. The model was successfully validated by comparing the predicted speed and power values with experimental ground reactions data collected in situ.

International audience; Under race conditions, the start directly influences an athlete’s performance. Taking into account the difficulties coming from the specific parameters relative to the start, comparing the swimmer’s movement with the kinematic data stays the best approach to understand the motion. The model of the present work was developed through this approach allowing us to pre- dict the swimmer’s performance (trajectory, velocity) and the joint moment of each articulation during the impulse phase of the grab start. This model defines kinematical and dynamical data with the following mean dispersions: 9 % for horizontal and total speed at the instant of take off, 1 % for the swim- mer’s internal joint power. By means of this model, it becomes possible to analyze and understand the joint moment of each articulation and the segmental coordination for each swimmer performing a grab start.