MINIMAXX PLAYER LOAD AS AN INDEX OF THE CENTER OF MASS DISPLACEMENT? A VALIDATION STUDY

The purpose of this study was to assess the concurrent validity of the player load computed by the MinimaxX accelerometers by comparing it to the player load computed by a gold standard method based on in series force platforms. Fourteen participants were instrumented with two accelerometers (MinimaxX S4, Catapult, Australia) during specific team sport displacements performed on the force plates. Pearson correlation coefficients were ranged from 0.74 to 0.93 while the coefficients of variation varied from 6.9 to 16.4%. The standard error of the estimate was small

LES DETERMINANTS MECANIQUES ET NEUROPHYSIOLOGIQUES DE LA PERFORMANCE EN TIR A L’ARC : INCIDENCES SUR L’ENTRAINEMENT

International audienceL’objectif de ce travail est de caractériser les stratégies musculaires intervenant dans le tir àl’arc, mais également de déterminer leur évolution au décours de la fatigue. Ainsi l’influencede l’apparition d’un phénomène de fatigue neuro-musculaire sur la performance en tir à l’arcpourra être déterminée. Une programmation spécifique de renforcement musculaire pourraalors être établie dans le double objectif d’améliorer la performance, mais également deréduire les risques de pathologie de l’épaule

Virage : Une réflexion pluridisciplinaire autour du temps dans la création numérique

We present in this article the development of the Virage project. This project aims to create a platform software for writting time and interaction in the context of digital stage management for living art. This project tries to answer some questions risen by a work group of AFIM (the french association for computer music). The project intends to produce a state of the art of the digital stage management, and to use this state to develop a prototype sotware. This propotype will be used in real conditions of stage management to get manager's points of view about our choices

Fast Autofocusing using Tiny Transformer Networks for Digital Holographic Microscopy

The numerical wavefront backpropagation principle of digital holography confers unique extended focus capabilities, without mechanical displacements along z-axis. However, the determination of the correct focusing distance is a non-trivial and time consuming issue. A deep learning (DL) solution is proposed to cast the autofocusing as a regression problem and tested over both experimental and simulated holograms. Single wavelength digital holograms were recorded by a Digital Holographic Microscope (DHM) with a 10$\mathrm{x}$ microscope objective from a patterned target moving in 3D over an axial range of 92 $\mu$m. Tiny DL models are proposed and compared such as a tiny Vision Transformer (TViT), tiny VGG16 (TVGG) and a tiny Swin-Transfomer (TSwinT). The experiments show that the predicted focusing distance $Z_R^{\mathrm{Pred}}$ is accurately inferred with an accuracy of 1.2 $\mu$m in average in comparison with the DHM depth of field of 15 $\mu$m. Numerical simulations show that all tiny models give the $Z_R^{\mathrm{Pred}}$ with an error below 0.3 $\mu$m. Such a prospect would significantly improve the current capabilities of computer vision position sensing in applications such as 3D microscopy for life sciences or micro-robotics. Moreover, all models reach state of the art inference time on CPU, less than 25 ms per inference

Endurance and strength training effects on physiological and muscular parameters during prolonged cycling

International audiencePurpose: This study investigated the effects of a combined endurance and strength training on the physiological and neuromuscular parameters during a 2-hour cycling test.Methods: Fourteen triathletes were assigned to an endurance-strength training group (ES) and an endurance-only training group (E). They performed 3 experimental trials before and after training: an incremental cycling test to exhaustion, a maximal concentric lower-limbs strength measurement and a 2-hour cycling exercise. Physiological parameters, free cycling chosen cadence (FCC) and the EMG of Vastus Lateralis (VL) and Rectus Femoris (RF) were analysed during the 2-hour cycling task.Results: The results showed that the maximum strength and the isometric maximal voluntary contraction (isoMVC) after training were significantly higher (P<0.01) and lower (P<0.01) than before training, respectively in ES and E groups. The physiological variables measured during the cycling tests and the progressive increase (P<0.01) in EMGi (VL) and EMGi (RF) throughout the 2-hour cycling test did not differ between the two groups before and after training, except for the variation of EMGi (VL) over the cycle time which was stabilized during the second hour of the 2-hour cycling test due to training in ES group. The decrease in FCC observed in pre-training (P<0.01) was also replaced by a steady FCC for the ES-group during the second hour of exercise.Conclusion: This study confirmed the decrease in the FCC with exercise duration and demonstrated that a specific combined endurance and strength training can prevent this decrease during a 2-hour constant cycling exercise

Mise à jour des recommandations du GEFPICS pour l’évaluation du statut HER2 dans les cancers du sein en France

En Europe, les patientes atteintes d’un cancer du sein invasif susceptibles de recevoir un traitement ciblé anti-HER2 sont actuellement sélectionnées sur la base d’un test immunohistochimique (IHC). Les techniques d’hybridation in situ (HIS) doivent être utilisées pour l’évaluation des cas IHC ambigus (2+) et pour l’étalonnage de la technique IHC. Les patientes éligibles au traitement ciblant HER2 présentent un statut HER2 positif défini par un test IHC 3+ ou un test 2+ amplifié. Une détection correcte du statut HER2 est indispensable à une utilisation optimale des thérapeutiques ciblées puisque leur efficacité est limitée aux patientes surexprimant HER2. Il est capital que l’évaluation du statut HER2 soit optimisée et fiable. Ces recommandations du groupe d’étude des facteurs pronostiques IHC dans le cancer du sein (GEFPICS) détaillent et commentent les différentes étapes des techniques IHC et HIS, les contrôles utilisables et les règles générales de l’apprentissage de la lecture. Une fois acquis, ce savoir-faire doit être pérennisé par l’observation de règles de bonnes pratiques techniques (utilisation rigoureuse de témoins internes et externes et participation régulière à des programmes d’Assurance qualité [AQ])., Summary In Europe, patients who may benefit from an HER2 targeted drug are currently selected by immunohistochemistry (IHC). In situ hybridization (ISH) techniques should be used for complementary assessment of ambiguous 2+ IHC cases and for the calibration of the IHC technique. Eligibility to an HER2 target treatment is defined by an HER2 positive status being IHC test 3+ or 2+ amplified. Reliable detection of HER2 status is essential to the appropriate usage of HER2 targeted drugs because its specificity is limited to tumors overexpressing HER2. It is essential that the IHC evaluation of the HER2 status of a mammary carcinoma is optimized and reliable. This GEFPICS’ guidelines look over the different steps of the IHC technique, the controls and, the rules for interpretation. Once acquired, this knowledge must be perpetuated by the observation of rules of good technical practice (internal and external controls, quality assurance programs)

Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND: Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori. OBJECTIVES: To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started. SEARCH METHODS: We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively. SELECTION CRITERIA: We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as13C or14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities. MAIN RESULTS: We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons. AUTHORS' CONCLUSIONS: In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions

Influence of training background on the relationships between plantarflexor intrinsic stiffness and overall musculoskeletal stiffness during hopping

International audienceThe aim of this study was to characterize the influence of intrinsic musculotendinous and musculoartic-ular stiffness of plantarflexor muscles on (1) the overall musculoskeletal stiffness and (2) the performance during stretch-shortening cycles-type exercise. The influence of plyometric training background on these relationships was also analyzed. Musculotendinous (SI MT), passive (K P) and active (SI MA) musculoarticular stiffnesses were quantified, using quick-release and sinusoidal perturbation tests, on nine French elite long or triple jumpers (athlete group, AG) and nine control subjects (CG). These ergometric parameters were related with the lower-limb stiffness (K leg) and the maximal performance (H max) measured from a force platform during vertical hopping. AG showed a significantly higher SI MT (2.76 rad-1), K P (55.6 N m rad-1), K leg (30.3 kN m-1) and H max (0.48 m) compared to CG (1.83 rad-1 , 37.8 N m rad-1 , 19.6 kN m-1 and 0.38 m, respectively). K leg was not significantly correlated with any of the intrinsic stiffness parameters (SI MT , SI MA or K P). For AG, a strong and negative correlation was observed between H max and K leg. These data indicate that, while elite jumpers presented higher stiffness of both musculotendi-nous and passive musculoarticular structures, a high compliance of musculoskeletal system was beneficial to optimize the performance in vertical hopping for these athletes. We suggested that neuromuscular strategies were designed to counterbalance this higher intrinsic stiffness to solve the problem of the conflicting requirement of the musculotendinous elements: increase in compliance to enhance the elastic recoil and increase in stiffness for a better force transmission to the periphery

Evaluation des propriétés mécaniques de la cheville chez des sauteurs en longueur, triple sauteurs, gymnastes aérobic et coureurs de fond "elites"

ObjectifL'objet de cette étude est d'analyser les éventuelles modifications des propriétés mécaniques musculo-tendineuses des fléchisseurs plantaires chez des sportifs de haut niveau d'activités sportives sollicitant différemment l'articulation de la cheville. Par ailleurs, les relations de ces propriétés mécaniques avec, d'une part, les propriétés de raideur du système musculo-squelettique global et d'autre part, les performances lors de sauts verticaux sont également analysées.MéthodologieTrente cinq sujets masculins [8 sauteurs (groupe S); triple saut, n=3; saut en longueur, n=5) 8 spécialistes d'aérobic sportive (groupe A), 10 spécialistes de course à pied de demi-fond ou de fond (groupe C), tous d'un niveau national ou international, et 9 sujets témoins (groupe T)] participent à l'étude. Ils sont évalués à partir des tests de quick-release et de perturbations sinusoïdales pour la détermination des propriétés de raideur musculo-tendineuse (iRMT) et musculo-articulaire active (iRMA) et passive (Kp), respectivement. Par ailleurs, des tests de sauts verticaux permettent de déterminer la raideur musculo-squelettique globale (KMI) et les hauteurs maximales atteintes (Hmax, HCMJ et HSJ).Résultats et discussionL'analyse montre un effet significatif (P0,05) avec les autres groupes.L'influence d'iRMT sur KMI reste limitée. De plus, en ce qui concerne la raideur mesurée en condition de sauts verticaux (KMI), elle est corrélée à Hmax pour les groupes S (R= -0,89; P<0,005) et A (R= -0.89; P<0,05). Pour les gymnastes, KMI est également corrélée négativement à HCMJ (R= -0,90; P<0.05). Les corrélations entre la raideur musculo-squelettique (KMI), mesurée pendant le test des rebonds, et la hauteur lors de ce test (Hmax) sont négatives pour le groupe de sauteurs et de gymnastes. Autrement dit, plus la compliance des membres inférieurs est grande et plus l'athlète saute haut. Les observations contradictoires concernant les adaptations des propriétés mécaniques chez les sportifs de haut niveau et leur influence sur la performance mettent en évidence la complexité des relations entre les caractéristiques élastiques des différentes structures anatomiques sollicitées lors des activités de type SSC.ConclusionNotre étude montre que pour résoudre la balance entre compliance et raideur, l'adaptation des propriétés mécaniques intrinsèques se réalise dans le sens d'une raideur accrue chez les sportifs de haut niveau afin de transmettre la force de manière plus efficace à la périphérie lors de la phase de restitution. Ce sont les athlètes dont le fonctionnement neuromusculaire permettra de contre-balancer cette augmentation de raideur, nécessaire par ailleurs, qui présenteront les performances les plus élevées

Intrinsic ankle and hopping leg-spring stiffness in distance runners and aerobic gymnasts

International audienceThe objective of this study was to examine the contribution of intrinsic ankle stiffness to leg-spring stiffness in high level athletes using various musculotendinous solicitations. Eight aerobic gymnasts (G), 10 long-distance runners (R) and 7 controls (C) were evaluated using quick-release or sinusoidal perturbation tests in order to quantify their respective plantarflexor musculotendinous (SI MT), ankle musculoarticular active (SI MA) and passive (K P) stiffness. Leg-spring stiffness (K leg) was measured during vertical hopping. Runners and gymnasts presented significantly higher SI MT values (P<0.01) than controls: 60.4 (±14.1) rad-1 .kg 2/3 for G, 72.7 (±23.8) rad-1 .kg 2/3 for R and 38.8 (±6.5) for C. In addition, normalized K leg were not significantly different between G, R and C. It appeared that intrinsic ankle stiffness had no influence on leg-spring stiffness. The adaptation of SI MT seems to concern specifically the active part of the series elastic component in runners. The results suggested that the number of stretch-shortening cycles during daily practice sessions, rather than their intensity, act as the determinant for this component