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ObjectivesTo identify individual characteristics associated with the adoption of injury risk reduction programmes (IRRP) and to investigate the variations in sociocognitive determinants (ie, attitudes, subjective norms, perceived behavioural control and intentions) of IRRP adoption in athletics (track and field) athletes.MethodsWe conducted a cross-sectional study using an online survey sent to athletes licensed with the French Federation of Athletics to investigate their habits and sociocognitive determinants of IRRP adoption. Sociodemographic characteristics, sports practice and history of previous injuries were also recorded. Logistic regression analyses and group comparisons were performed.ResultsThe final sample was composed of 7715 athletes. From the multivariable analysis, competing at the highest level was positively associated with IRRP adoption (adjusted OR (AOR)=1.66; 99.9% CI 1.39 to 1.99 and AOR=1.48; 99.9% CI 1.22 to 1.80) and presenting a low number of past injuries was negatively associated with IRRP adoption (AOR=0.48; 99.9% CI 0.35 to 0.65 and AOR=0.61; 99.9% CI 0.44 to 0.84), both during their lifetime and the current season, respectively. These results were supported by higher scores of sociocognitive determinants among athletes who reported IRRP adoption compared with other athletes.ConclusionSome characteristics of athletes seem to be associated with IRRP adoption either positively (competing at the highest level) or negatively (presenting a lower number of past injuries), whereas all the sociocognitive determinants tested appear to be linked to IRRP adoption. Since many athlete characteristics are difficult or impossible to change, IRRP promotion may be enhanced by targeting athletes’ beliefs and intentions to adopt an IRRP.

Cancer-related fatigue can continue long after curative cancer treatment. The aim of this study was to investigate sleep and rest–activity cycles in fatigued and non-fatigued cancer survivors. We hypothesized that sleep and rest–activity cycles would be more disturbed in people experiencing clinically-relevant fatigue, and that objective measures of sleep would be associated with the severity of fatigue in cancer survivors. Cancer survivors (n = 87) completed a 14-day wrist actigraphy measurement to estimate their sleep and rest–activity cycles. Fatigue was measured using the Functional Assessment of Chronic Illness Therapy Fatigue Scale (FACIT-F). Participants were dichotomised into two groups using a previously validated score (fatigued n = 51 and non-fatigued n = 36). The participant’s perception of sleep was measured using the Insomnia Severity Index (ISI). FACIT-F score was correlated with wake after sleep onset (r = −0.28, p = 0.010), sleep efficiency (r = 0.26, p = 0.016), sleep onset latency (r = −0.31, p = 0.044) and Insomnia Severity Index (ISI) score (r = −0.56, p &lt, 0.001). The relative amplitude of the rest–activity cycles was lower in the fatigued vs. the non-fatigued group (p = 0.017, d = 0.58). After treatment for cancer, the severity of cancer-related fatigue is correlated with specific objective measures of sleep, and there is evidence of rest–activity cycle disruption in people experiencing clinically-relevant fatigue.

PurposeTo determine associations between thermal responses, medical events, performance, heat acclimation and health status during a World Athletics Championships in hot-humid conditions.MethodsFrom 305 marathon and race-walk starters, 83 completed a preparticipation questionnaire on health and acclimation. Core (Tcore; ingestible pill) and skin (Tskin; thermal camera) temperatures were measured in-competition in 56 and 107 athletes, respectively. 70 in-race medical events were analysed retrospectively. Performance (% personal best) and did not finish (DNF) were extracted from official results.ResultsPeak Tcore during competition reached 39.6°C±0.6°C (maximum 41.1°C). Tskin decreased from 32.2°C±1.3°C to 31.0°C±1.4°C during the races (pcore was not related to DNF (25% of starters) or medical events (p≥0.150), whereas Tskin, Tskin rate of decrease and Tcore-to-Tskin gradient were (p≤0.029). A third of the athletes reported symptoms in the 10 days preceding the event, mainly insomnia, diarrhoea and stomach pain, with diarrhoea (9% of athletes) increasing the risk of in-race medical events (71% vs 17%, pcore (39.4°C±0.4°C vs 39.8°C±0.7°C, p=0.044) and larger in-race decrease in Tskin (−1.4°C±1.0°C vs −0.9°C±1.2°C, p=0.060), than non-acclimated athletes. Although not significant, they also showed lower DNF (19% vs 30%, p=0.273) and medical events (19% vs 32%, p=0.179).ConclusionTskin, Tskin rate of decrease and Tcore-to-Tskin gradient were important indicators of heat tolerance. While heat-acclimated athletes ranked better, recent diarrhoea represented a significant risk factor for DNF and in-race medical events.

New findings What is the central question of this study? What are the effects of repeated subclinical vaso-occlusions on nuclear factor erythroid 2 related factor 2 (Nrf2) and oxidative stress balance regulation in the kidney of transgenic SAD mice? What is the main finding and its importance? In response to hypoxia-reoxygenation, nuclear Nrf2 protein expression decreased in the kidney of SAD mice while haem oxygenase transcripts were increased. This suggest that in SAD mice, other transcription factors than Nrf2 could be involved in renal antioxidant gene regulation in response to hypoxia-reoxygenation. Abstract Hypoxia-reoxygenation (H/R) stress is known to increase oxidative stress in transgenic sickle mice and can cause organ failure. Here we described the effects of H/R on nuclear factor erythroid 2-related factor 2 (Nrf2) as a putative regulator of redox status in the kidneys of SAD mice investigating Nrf2-regulated antioxidant enzymes. Transgenic SAD mice and healthy C57Bl/6J mice were exposed to 4 h of hypoxia followed by various times of reoxygenation at ambient air (2 or 6 h). Regardless of the conditions (i.e. normoxia or H/R), SAD mice expressed higher renal oxidative stress levels. Nuclear Nrf2 protein expression decreased after 2 h post-hypoxia only in the medulla region of the kidney and only in SAD mice. Simultaneously, haem oxygenase transcripts were affected by H/R stimulus with a significant enhancement after 2 h post-hypoxia. Similarly, hypoxia inducible factor-1α staining increased after 2 h post-hypoxia in SAD mice in both cortex and medulla areas. Our data confirm that the kidneys are organs that are particularly sensitive to H/R stimuli in sickle cell SAD mice. Also, these results suggest an effect of the duration of recovery period (short vs. long) and specific responses according to kidney areas, medulla vs. cortex, on Nrf2 expression in response to H/R stimuli in SAD mice.

Duchenne muscular dystrophy (DMD) is characterized by progressive muscle wasting following repeated muscle damage and inadequate regeneration. Impaired myogenesis and differentiation play a major role in DMD as well as intracellular calcium (Ca2+) mishandling. Ca2+ release from the sarcoplasmic reticulum is mostly mediated by the type 1 ryanodine receptor (RYR1) that is required for skeletal muscle differentiation in animals. The study objective was to determine whether altered RYR1-mediated Ca2+ release contributes to myogenic differentiation impairment in DMD patients. The comparison of primary cultured myoblasts from six boys with DMD and five healthy controls highlighted delayed myoblast differentiation in DMD. Silencing RYR1 expression using specific si-RNA in a healthy control induced a similar delayed differentiation. In DMD myotubes, resting intracellular Ca2+ concentration was increased, but RYR1-mediated Ca2+ release was not changed compared with control myotubes. Incubation with the RYR-calstabin interaction stabilizer S107 decreased resting Ca2+ concentration in DMD myotubes to control values and improved calstabin1 binding to the RYR1 complex. S107 also improved myogenic differentiation in DMD. Furthermore, intracellular Ca2+ concentration was correlated with endomysial fibrosis, which is the only myopathologic parameter associated with poor motor outcome in patients with DMD. This suggested a potential relationship between RYR1 dysfunction and motor impairment. Our study highlights RYR1-mediated Ca2+ leakage in human DMD myotubes and its key role in myogenic differentiation impairment. RYR1 stabilization may be an interesting adjunctive therapeutic strategy in DMD.

International audience; Background: Left ventricular (LV) remodeling, characterized by increased LV hypertrophy and depressed function, is observed in strength-trained athletes who use anabolic-androgenic steroids (AAS). Previous studies reported an increase in cardiac fibrosis in these athletes, which could promote intraventricular dyssynchrony. In this context, this study evaluated LV dyssynchrony in strength-trained athletes using AA; hypothesizing that the use of AAS leads to an increase in LV dyssynchrony with an increase in post-systolic shortening.Methods: Forty-four participants (aged 20-40 years) were divided into three age-matched groups: strength-trained athletes using AAS (users, n=14) and those who were not (non-users, n=15), and healthy sedentary men (controls, n=15),. After completing a survey, each participant was assessed with 2D-strain echocardiography. Left ventricular dyssynchrony was quantified using the standard deviation of the time to peak for longitudinal strains (SD), the longitudinal strain delay index (LSDI) and the segmental post-systolic index (PSI).Results: Users exhibited a greater LV mass index and higher systolic and diastolic functions than both controls and non-users. The decrease in LV strains in users was predominantly observed at the interventricular segments. The SD, LSDI and PSI, calculated on the basal inferoseptal, basal anteroseptal and basal inferolateral segments, were higher in users.Conclusion: The results strongly support that the specific LV remodeling observed in young AAS users was associated with an increase in LV dyssynchrony. The correlations with ejection fraction suggested that wasted energy, due to post-systolic shortenings, contributed in part to the decrease in LV function in strength-trained athletes using AAS.

Atherosclerosis is a chronic systemic inflammatory disease, inducing cardiovascular and cerebrovascular acute events. A role of neuroinflammation is suspected, but not yet investigated in the gyrencephalic brain and the related activity at blood−brain interfaces is unknown. A non-human primate model of advanced atherosclerosis was first established using longitudinal blood samples, multimodal imaging and gene analysis in aged animals. Non-human primate carotid lesions were compared with human carotid endarterectomy samples. During the whole-body imaging session, imaging of neuroinflammation and choroid plexus function was performed. Advanced plaques were present in multiple sites, premature deaths occurred and downstream lesions (myocardial fibrosis, lacunar stroke) were present in this model. Vascular lesions were similar to in humans: high plaque activity on PET and MRI imaging and systemic inflammation (high plasma C-reactive protein levels: 42 ± 14 µg/ml). We also found the same gene association (metabolic, inflammatory and anti-inflammatory markers) as in patients with similar histological features. Metabolic imaging localized abnormal brain glucose metabolism in the frontal cortex. It corresponded to cortical neuro-inflammation (PET imaging) that correlated with C-reactive protein level. Multimodal imaging also revealed pronounced choroid plexus function impairment in aging atherosclerotic non-human primates. In conclusion, multimodal whole-body inflammation exploration at the vascular level and blood−brain interfaces identified high-risk aging atherosclerosis. These results open the way for systemic and central inflammation targeting in atherosclerosis in the new era of immunotherapy., Elevated cortical inflammation and defective choroid plexus activity associate with high-risk atherosclerosis in cynomolgus monkeys. Using diet-induced atherosclerosis, in-vivo imaging and gene analysis, Di Cataldo et al. showed (i) monkeys exhibit similar atherosclerosis features and vulnerable plaques-associated genes as patients, (ii) brain imaging demonstrated frontal cortex neuroinflammation and neurovascular signs., Graphical Abstract Graphical Abstract

Resume Objectif Realiser un etat des lieux des connaissances actuelles concernant la prevention des blessures chez le skieur alpin de competition, âge de 14 a 19 ans, en suivant la sequence de prevention des blessures en 4 etapes de van Mechelen et al. (1992). Methode Une revue systematique a ete effectuee en novembre 2018 en utilisant deux moteurs de recherche (« Pub Med » et « Science Direct ») et les mots cles suivants : « Injury », « Sports injuries », « Young », « Adolescent », « Epidemiology », « Risk factor », « Prevention », « Alpine skiing » et « Alpine ski » pour inclure les articles traitant de l’epidemiologie, l’identification de facteurs de risque, la mise en place et/ou l’evaluation des programmes de prevention des blessures du skieur alpin de competition âge de 14 a 19 ans. Resultats Cinq etudes rapportaient des resultats concernant l’epidemiologie des blessures du skieur alpin de competition âge de 14 a 19 ans ; ces blessures etaient majoritairement localisees au genou concernant les ligaments et la blessure la plus frequente etait la lesion du ligament croise anterieur (LCA). Deux etudes identifiaient l’asymetrie de force entre les muscles flechisseurs et extenseurs du rachis, ainsi que l’asymetrie de performance au one leg hop test comme facteurs de risque de lesion du LCA. Une etude a rapporte qu’un programme de prevention base sur l’amelioration du controle neuromusculaire des membres inferieurs et le renforcement des muscles du rachis limitait le nombre de lesions du LCA. Discussion et conclusion Les lesions du LCA etaient les plus frequentes chez le skieur alpin de competition âge de 14 a 19 ans;un faible controle neuromusculaire ainsi qu’une asymetrie de musculature du tronc seraient predictifs de cette lesion, et il semblerait que la mise en place d’un programme de prevention puisse diminuer la survenue de cette blessure. Cependant, d’autres etudes longitudinales cherchant a identifier les facteurs de risque potentiels, leur evolution dans le temps et leur modification par des programmes de prevention sont necessaires. Niveau de preuve 4.

ObjectiveCarotid atherosclerotic plaques are a source of emboli for stroke. ‘Unstable’ carotid atherosclerotic plaques may have intraplaque haemorrhages, neovessels, prevalent macrophages, excessive calcium deposits, a large lipid core and a thin fibrous cap. Regular physical activity (PA) may lower the risk of plaques becoming unstable. We evaluated the association of both PA and sedentary behaviour (SB) with carotid plaque histopathology.Methods90 asymptomatic patients who were undergoing carotid endarterectomy for carotid artery narrowing identified on ultrasound reported their PA and SB by questionnaires. We calculated PA intensity in MET (metabolic equivalent of task)-min/week. For analysis, the population was divided into tertiles according to PA (T1PA: the less PA patients; T2PA: the intermediate PA patients; T3PA: the most physically active patients) (T1PAResultsIntraplaque haemorrhage was less frequent in the most physically active tertile (T3PA, 48%) versus T1PA (74%) and in the least sedentary tertile T1SB (50%) versus T3SB (71%). The intraplaque haemorrhage was less frequent in those who exercised more than 900 MET-min/week (59% vs 47% for >900 and ConclusionIn this cross-sectional study of asymptomatic patients who underwent endarterectomy (i) higher reported PA, (ii) intensity of PA and (iii) lower reported SB were associated with lower prevalence of intraplaque haemorrhage. This could be a mechanism whereby PA protects against cerebrovascular disease (stroke) and death.

To compare the effects of local-vibration and active warm-up on knee extensors muscle stiffness and neuromuscular performance.Experimental crossover study.Thirteen participants performed three 15-min warm-up protocols of control (CON), active (ACT) and local-vibration (LV) in separate testing session. Passive stiffness of vastus lateralis (VL) and vastus medialis (VM) by shear wave elastography and neuromuscular performance were assessed before and 2-min after each condition.A decrease in muscle stiffness was reported after ACT for VL (-16.0±6.6%; p0.001) and VM (-10.2±8.7%; p=0.03) while no changes were reported after CON (p=0.46 and p=0.34 for VL and VM, respectively) and LV (p=0.07 and p=0.46 for VL and VM, respectively). Maximal jump performances increased during squat (+8.5±6.6%; p0.001) and countermovement jump (+5.2±5.8%; p0.001) after ACT while no changes were reported after CON and LV during squat (p=0.16 and p=0.81, respectively) and countermovement jump (p=0.18 and p=0.31, respectively). We further report that each condition was ineffective to inducing changes in maximal voluntary isometric contraction force (p=0.18), rate of force development (p=0.92), twitch parameters (p0.05) as well as central modulations as reported by the unchanged voluntary activation level (p=0.24) and maximal electromyography (EMG) recorded from the VL (p=0.44).The active warm-up acutely reduced muscle stiffness and increased muscle performance during maximal dynamic tasks. With regard to LV, further studies are required to determine optimal parameters (frequency, amplitude, duration) to significantly increase muscle performance.

Background The variation of the anterolateral ligament (ALL) length during knee motion is still unclear, and the knee position in which a reconstruction graft should be tensioned remains controversial. The objective of this study was to determine the variation of the ALL length during knee motion using a three-dimensional optoelectronic system. Methods Kinematic analyses of 20 cadaveric knees were performed using a Motion Analysis® system. The variability of the measurements made during the five acquisition cycles was studied. Reliability was evaluated by two separate measurement sessions, with complete system reinstallation, using different cadavers and a new operator. The ALL length was analysed from extension to full flexion in three rotational conditions. Findings When analysing the reliability of the five cycles, 82% of the measurements we found to have an Intra Class Correlation (ICC) >0.85. The reproducibility of inter-sessional measures by different operators and different cadavers was either good (ICC >0.75) or excellent (ICC >0.85). The ALL length was maximum in full internal rotation with the knee at 25° of flexion. Interpretation This three-dimensional optoelectronic protocol allowed us to analyse the variation of the ALL length during intact knee motion with good reliability and the required accuracy to analyse this variable. The maximal length and highest tension of the ALL was reported at 25° of knee flexion in internal rotation, suggesting this as the optimal position for the knee joint when tensioning an ALL reconstruction.

International audience; Hydroxyurea (HU) has been suggested to act as a nitric oxide (NO) donor in sickle cell anemia (SCA). However, little is known about the HU NO-related effects on red blood cell (RBC) physiology and NO signalling pathway. Thirty-four patients with SCA (22 under HU treatment (HU+) and 12 without (HU-)) and 17 healthy subjects (AA) were included. RBC nitrite content, deformability and reactive oxygen species (ROS) levels were measured. RBC NO-synthase (RBC-NOS) signalling pathway was assessed by the measurement of RBC-NOS serine 1177 and RBC-AKT serine 473 phosphorylation. We also investigated the in vitro effects of Sodium Nitroprusside (SNP), a NO donor, on the same parameters in SCA RBC. RBC nitrite content was higher in HU+ than in HU-and AA. RBC deformability was decreased in SCA patients compared to AA but the decrease was more pronounced in HU-. RBC ROS level was increased in SCA compared to AA but the level was higher in HU-than in HU+. RBC-NOS serine 1177 and RBC-AKT serine 473 phosphorylation were decreased in HU+ compared to HU-and AA. SCA RBC treated with SNP showed increased deformability, reduced ROS content and a decrease in AKT and RBC-NOS phosphorylation. Our study suggests that HU, through its effects on foetal hemoglobin and possibly on NO delivery, would modulate RBC NO signalling pathway, RBC rheology and oxidative stress.

Aims Peripheral neuropathy (PN) in patients with diabetes can lead to changes in the distribution of plantar pressure during walking, which can be recorded with pedobarography. Compared to traditional spatial data reduction analysis, the pedobarographic Statistical Parametric Mapping (pSPM) allows comparison of the footprints with the advantage that sub-regions do not need to be defined a priori. Aim of the study was to test the potential of pSPM in identifying specific distribution of spatial pressure in different stages of PN. Methods PN was defined according to usual tools (i.e., tendon reflexes and sensory tests). Four groups were compared: patients with diabetes without PN (n = 24; 239 steps); with signs of mild PN (n = 12; 117 steps); with signs of severe PN (n = 6; 52 steps) and a control group without diabetes (n = 12; 124 steps). Traditional spatial data reduction and pSPM were performed to compare plantar pressures in the different groups. Results In patients with PN, traditional spatial data reduction analysis showed lower plantar pressures with PN severity. pSPM analysis is able to better define the initial changes: mild PN patients presents higher pressures on the anterior side of the metatarsal heads compared to patients without neuropathy. Patients with severe PN are characterised by higher pressures under the medial foot arch compared to other groups. Conclusions pSPM may identify specific features of plantar pressure distribution during walking in patients with mild PN and may become a useful screening tool for a timely identification of this complication.

International audience; Purpose: Both perceived and objectively-measured attributes of the built environment have been related to active transport. They do not refer, however, to the same construct: objective measurements provide an inventory of a neighborhood?s active-friendly attributes, while the perceptions of individuals refer to their appraisal of their neighborhood opportunities for active travel. Both aspects are complementary in explaining active transport. This study examines the independent associations of perceived and objective environmental attributes with active transport, and whether perceptions moderate the objectively-measured environment active transport relationship.Methods: Based on a sample of 2670 participants from the NutriNet-Sante? Study (France), we examined (i) the concordance between perceptions and objective measurements of residentialbased environmental attributes using kappa statistics, (ii) the associations between perceived and objectively-measured attributes and active transport by trip purpose (commuting and errand) using zero-inflated negative-binomial regressions, and (iii) the potential moderation effect of perceptions on the associations between objectively-measured environmental attributes and active transport. Information related to demographics, perceptions and transport modes was collected in 2013.Results: A poor to fair level of agreement was observed between perceived , objectively -measured environmental attributes; both were associated with active transport for commuting and errands. Environmental correlates differed between the likelihood to engage in active transport and the time spent in transport. Perceptions positively moderated the associations be-tween active transport and objectively-measured walkability and access to facilities. The differ-ences in predicted active transport time between a high versus low perception of the environmental attributes for a given neighborhood ranged from 20 to 55 min for active commuting , from 84 to 37 min for active transport for errands.Conclusion: Associations between objectively-measured environmental attributes and active transport are dependent on individuals & rsquo; perceptions of opportunities provided by their residential neighborhood. Increasing individuals & rsquo; awareness of active-friendly environmental attributes may be crucial for enhancing active transport.

Purpose: Exercise has been shown to improve physical and psychological conditions during cancer therapy, but mechanisms remain poorly understood. The purpose of the present study was to report the results of cancer-related biomarkers and metabolomics outcomes from the PASAPAS feasibility study. Methods: In the PASAPAS randomized controlled trial, 61 women beginning adjuvant chemotherapy for localized breast cancer were randomized in a 6-month program of weekly aerobic exercises associated with nutritional counseling versus usual care with nutritional counseling. In the present analysis of 58 women for whom blood samples were available, first, circulating levels of biomarkers (ie, insulin, insulin-like growth factor 1, estradiol, adiponectin, leptin, interleukin-6, and tumor necrosis factor α) were measured at baseline and 6-month follow-up. Changes in biomarkers were compared between exercisers (n = 40) and controls (n = 18) using mixed-effect models. Second, serum metabolites were studied using an untargeted 1H nuclear magnetic resonance spectroscopy, and orthogonal partial least squares analyses were performed to discriminate exercisers and controls at baseline and at 6 months. Results: Over the 6-month intervention, no statistically significant differences were observed between exercisers and controls regarding changes in biomarkers and metabolomic profiles. Conclusion: The present analysis of the PASAPAS feasibility trial did not reveal any improvement in circulating biomarkers nor identified metabolic signatures in exercisers versus controls during adjuvant breast cancer treatment. Larger studies preferably in women with poor physical activity level to avoid ceiling effect, testing different doses and types of exercise on additional biological pathways, could allow to clarify the mechanisms mediating beneficial effects of physical exercise during cancer treatment. Trial registration: ClinicalTrials.gov Identifier: NCT01331772. Registered 8 April 2011, https://clinicaltrials.gov/ct2/show/NCT01331772?term=pasapas&rank=1

International audience; Objective: To analyse the rates of lower limb muscle injuries in athletics disciplines requiring different running velocities during international athletics championships.Design: Prospective total population study.Methods: During 13 international athletics championships (2009–2019) national medical teams and local organizing committee physicians daily reported all newly incurred injuries using the same study design, injury definition and data collection procedures. In-competition lower limb muscle injuries of athletes participating in disciplines involving running (i.e. sprints, hurdles, jumps, combined events, middle distances, long distances, and marathon) were analysed.Results: Among the 12,233 registered athletes, 344 in-competition lower limb muscle injuries were reported (36% of all in-competition injuries). The proportion, incidence rates and injury burden of lower limb muscles injuries differed between disciplines for female and male athletes. The most frequently injured muscle group was hamstring in sprints, hurdles, jumps, combined events and male middle distances runners (43–75%), and posterior lower leg in female middle distances, male long distances, and female marathon runners (44–60%). Hamstring muscles injuries led to the highest burden in all disciplines, except for female middle distance and marathon and male long distance runners. Hamstring muscles injury burden was generally higher in disciplines requiring higher running velocities, and posterior lower leg muscle injuries higher in disciplines requiring lower running velocities.Conclusions: The present study shows discipline-specific injury location in competition context. Our findings suggest that the running velocity could be one of the factors that play a role in the occurrence/location of muscle injuries.

Swimming is a very demanding sport which requires extreme muscle strength and endurance. Only fractions of a second may separate the winner from the opponents. The swimming performance, specifically, is influenced by complex interactions between physiological, morphological, neuromuscular, biomechanical, and technical factors. These factors not only depend on training, genetics, and opportunity but also can be influenced by a “warm-up,” recognized as a primary factor in athletic performance. Completion of a warm-up prior to a competitive exercise bout is a widely accepted practice within modern sport; athletes and coaches believe that warm-up is very essential to attain optimal performance. Consequently, this thesis proposes an easy method for coaches to implement during the competition warm-up or before the race in call room to improve the performance of their athletes. This technique is called post-activation potentiation (PAP). However, the effects of PAP and swimming performance remains limited. Consequently, our three studies contributed to the knowledge of this subject. Our results provided practical information for coaches to develop appropriate training paradigms for their swimmers. The revealed data reported the importance of PAP individualization to enhance swimming performance and described some basics that should guide the warm-up structure in the competition. Many factors can affect the PAP impact on performance such as the transition time between the PAP stimulus and the subsequent main activity (swimming race), the typological profile and muscle strength of swimmers (the percentage of fast, slow fibers...), the level of training experience and the load or intensity of the PAP stimulus. Nevertheless, PAP effect in swimming still lack the information to understand how it works and specially to allow better application in practice. However, it is necessary for each trainer or physical trainer to proceed by trial and error to determine, for each athlete, what is the optimal recovery time in order to enhance the performance. According to the literature, the potentiation effect can be measured between 1min to 12 minutes before the race. This duration should be short enough to maintain potentiation but long enough not to induce an accumulation of fatigue. The optimal average time is often around 6 to 8 minutes, which corresponds to the time the swimmer waits in the call room. However, many protocols are to be tested, science must continue to study this phenomenon to know its most effective use in swimming performance; La natation est un sport singulier qui exige une force et une endurance musculaire extrême. Quelques fractions de seconde peuvent séparer le vainqueur de ses rivaux. La performance en natation est particulièrement influencée par des interactions complexes entre les facteurs physiologiques, morphologiques, neuromusculaires, biomécaniques et techniques. Ces facteurs dépendent non seulement de l’entraînement ou de la génétique, mais aussi d’un échauffement reconnu comme source déterminante de la performance athlétique. L’achèvement d’un échauffement avant une compétition demeure une pratique largement utilisée dans le sport moderne ; les athlètes et les entraîneurs considèrent que l’échauffement est essentiel pour atteindre une performance optimale. Par conséquent, la présente thèse propose une méthode facile à implémenter par les entraineurs durant l’échauffement dans une compétition ou avant la course dans la chambre d’appel afin d’améliorer la performance de leurs athlètes. Cette technique est la potentialisation par post-activation (PAP). Cependant, les connaissances sur les effets de la PAP et la performance en natation restent limités. Par conséquent, nos trois études ont contribué à améliorer notre connaissance sur ce sujet. Nos résultats semblent fournir des renseignements pratiques qui pourraient aider les entraîneurs à mettre au point des paradigmes d’entraînement appropriés pour leurs nageurs. Les données ont également montré la pertinence de l’individualisation de la PAP sur la performance des nageurs, déterminant quelques bilans importants qui devraient guider la structure d’échauffement dans la compétition. Plusieurs facteurs peuvent influencer l’effet de PAP sur la performance tels que le temps de transition entre le stimulus PAP et la course a mesurer, le profil typologique et la force musculaire des nageurs (le pourcentage de fibres rapides, lentes…), le niveau d’expérience d’entraînement et la charge ou l’intensité du stimulus PAP. Néanmoins, l’application du PAP en natation nécessite encore un certain nombre de recherches pour comprendre son fonctionnement et surtout pour permettre une meilleure application dans la pratique. Toutefois, il est nécessaire pour chaque entraîneur ou préparateur physique de procéder par essai-erreur pour déterminer, pour chaque athlète, quel est le temps de récupération optimale afin d'améliorer la performance désirée. Dans la littérature scientifique, selon le protocole utilisé, il est préférable de réaliser le PAP entre 1min et 12 minutes avant la course. Cette durée doit être suffisamment courte pour garder la potentialisation mais suffisamment longue pour ne pas induire une accumulation de fatigue. Le temps moyen optimal se situe souvent autour des 6-8 minutes et il correspond donc au moment où le nageur attend dans la chambre d’appel. Cependant, nombreux protocoles sont à tester, la science doit continuer à étudier ce phénomène pour en connaître son utilisation la plus efficace en natation de cours

International audience; Better understanding the psychological consequences of an injury and its influence on behavior changes and the implementation of a prevention program seems relevant for injury management (treatment and prevention). Thus, the objective of this present study was (1) to analyze the perception of injury by athletes, and (2) to analyze their influence on the realization of injury prevention measures.Methods: We conducted a national retrospective quantitative observational study to collect the feelings of competitive athletes licensed to the French Athletics Federation with respect to their injury history, their perception of the injury and the injury prevention programs, through a computer survey sent to athletes in spring 2020.Results: In all, 7712 responses from athletes were included in this analysis, including 37% women and 63% men, aged 37.9 ± 14.8 years (18 to 87 years), ranging from international to departmental level, covering all disciplines of athletics. Seventy percent of athletes had never completed an injury prevention program in their career, while 30% felt they had partially or fully completed one. Ninety percent of the athletes had had at least one injury since starting athletics. Athletes reported that an injury created sadness, frustration, disgust, and a worry about getting hurt in one place. They were aware that poor management of an injury could lead to a recurrence or a new injury. Athletes with a history of injury performed significantly more injury prevention program than those with no injury history. Athletes with previous injury believed in the effectiveness of injury prevention programs more than those without. On the other hand, there was no difference in the perception of the interest of preventive measures such as a healthy lifestyle, listening to your body, pain and fatigue between athletes with and without a history of injuries.Conclusion: We have reported that an injury can have significant psychological consequences on the athlete. These repercussions are important to consider in the overall management of injuries, e.g. in the treatment, return to the field and prevention of injuries.; Mieux comprendre les conséquences psychologiques d’une blessure et l’influence de celle-ci sur les modifications de comportement et la réalisation d’un programme de prévention semble pertinent pour la prise en charge thérapeutique et dans une optique de prévention. Ainsi, l’objectif de cette présente étude a donc été (1) d’analyser la perception des blessures par les athlètes, et (2) d’analyser l’influence de celles-ci sur la réalisation de mesures de prévention.Méthodes : Nous avons conduit une étude observationnelle quantitative rétrospective nationale de recueil du ressenti des athlètes de compétition licenciés à la Fédération française d’athlétisme vis-à-vis de leurs antécédents de blessures, leur perception de la blessure et les programmes de prévention des blessures, par un questionnaire informatique envoyé aux athlètes au printemps 2020.Résultats : Au total, 7712 réponses d’athlètes ont été incluses dans cette analyse, incluant 37 % de femmes et 63 % d’hommes, âgés de 37,9 ± 14,8 ans (de 18 à 87 ans), allant de niveau international à départemental, couvrant toutes les disciplines de l’athlétisme. Soixante-dix pour cent des athlètes n’avaient jamais réalisé de programme de prévention des blessures durant leur carrière, alors que 30 % estimaient en avoir suivi un de manière partielle ou totale. Quatre-vingt dix pour cent des athlètes avaient eu au moins une blessure depuis le début de leur pratique. Les sportifs rapportaient qu’une blessure engendrait une tristesse, une frustration, un dégoût et une préoccupation de se refaire mal au même endroit. Ils étaient conscients qu’une mauvaise prise en charge pouvait entraîner une récidive ou une nouvelle blessure. Les athlètes avec antécédent de blessure réalisaient significativement plus un programme de prévention des lésions que ceux ne s’étant jamais blessés. Ceux s’étant déjà blessés croyaient en l’efficacité des programmes de prévention, davantage que ceux sans antécédent de blessure. En revanche, il n’y avait pas de différence de perception de l’intérêt de mesures préventives telles que l’hygiène de vie, l’écoute de son corps, de ses douleurs et de sa fatigue entre les athlètes avec et sans antécédent de blessures.Conclusion : Une blessure peut entraîner des conséquences psychologiques non négligeables pour l’athlète. Ses répercussions sont importantes à prendre en compte dans la prise en charge globale des lésions.

International audience

Resume Introduction Modifier les habitudes de vie vers plus d’activite physique des femmes atteintes de cancer du sein est aujourd’hui un objectif majeur des prises en charge. L’objectif de cette etude etait de tester de maniere exploratoire l’impact de l’evolution du profil d’activite quotidienne sur la qualite de vie aupres de ce public. Methodes Soixante patientes (18 a 75 ans) atteintes de cancer du sein non metastatique ont ete randomisees selon un ratio 2/1 (intervention en activite physique ; controle) dans le cadre de l’essai clinique randomise PASAPAS. Des analyses de regression lineaire multiples ont ete effectuees afin d’expliquer les scores de qualite de vie six mois apres le debut des traitements adjuvants. Variables explicatives retenues : score de qualite de vie en debut d’etude, trait d’anxiete, bras de randomisation, variations du temps passe dans differentes classes d’activite physique ([3-4[MET, [4-6[MET, ≥ 6 MET) et dans des comportements sedentaires. Resultats Seule la diminution du temps passe dans des comportements sedentaires est veritablement apparue comme un predicteur de la qualite de vie physique. La participation au groupe d’intervention est apparue comme un predicteur de la qualite de vie mentale. Discussion Les resultats plaident pour l’intensification de la lutte contre la sedentarite dans les objectifs de prise en charge des femmes atteintes de cancer du sein, ainsi que pour la mise place d’un accompagnement collectif encadre par des personnels competents. Ils suggerent egalement de s’interesser a l’effet de la dynamique d’evolution du profil d’activite quotidienne sur la qualite de vie.

BACKGROUND Erythrocyte deformability is impaired in sickle cell disease (SCD). The regulation of cytoskeletal protein organization plays a key role in erythrocyte deformability. The activation of adenylyl cyclase (AC)/cAMP/Protein kinase A (PKA) signaling pathway was associated with increased deformability in healthy erythrocytes, however the role of this pathway in SCD is unknown. OBJECTIVE We evaluated mechanical responses of sickle red blood cells under physiological levels of shear stress and the possible link between their deformability and AC/cAMP/PKA signaling pathway. METHODS The shearing of sickle red blood cells at physiological level (5 Pa) and the measurement of deformability were performed by a laser assisted optical rotational cell analyzer (LORRCA). RESULTS Red blood cell deformability increased of 2.5-6.5% by blocking the activity of phosphodiesterase with Pentoxifylline (10μM) (p

International audience

Blood rheology is a key determinant of blood flow and tissue perfusion. There are still large discrepancies regarding the effects of an acute running exercise on blood rheological properties and red blood cell (RBC) physiology. We investigated the effect of a 10 km running trial on markers of blood rheology and RBC physiology in endurance trained athletes. Blood was sampled before and after the exercise to measure lactate and glucose, hematological and hemorheological parameters (blood viscosity, RBC deformability, and aggregation), eryptosis markers (phosphatidylserine and CD47 exposure, RBC reactive oxygen species), RBC-derived microparticles (RBC-MPs), and RBC electrophysiological activity. Weight was measured before and after exercise. Peripheral oxygen saturation and heart rate were monitored before and during the trial. Blood lactate and glucose levels increased after exercise and subjects significantly lost weight. All athletes experienced a significant fall in oxygen saturation. Mean corpuscular volume (MCV) was increased from 95.1 ± 3.2 to 96.0 ± 3.3 and mean corpuscular hemoglobin concentration (MCHC) decreased after exercise suggesting a slight RBC rehydration. Exercise increased RBC deformability from 0.344 ± 0.04 to 0.378 ± 0.07, decreased RBC aggregates strength and blood viscosity, while hematocrit (Hct) remained unaffected. While RBC electrophysiological recording suggested a modulation in RBC calcium content and/or chloride conductance, eryptosis markers and RBC-MPs were not modified by the exercise. A 10 km acute running exercise had no effect on RBC senescence and membrane blebbing. In contrast, this exercise increased RBC deformability, probably through rehydration process which resulted in a decrease in blood viscosity.

Lateral patellofemoral osteoarthritis is a relatively common condition in young, active patients. Partial lateral patellar facetectomy is a relatively minimally invasive option to restore knee function and return to sport when conservative treatments are insufficient. We describe the arthroscopic technique of partial lateral patellar facetectomy , which has been historically performed as an open procedure. We describe preoperative planning, arthroscopic portals, landmarks, intra-articular evaluation of bone resection, and surgical difficulties. The goal of the preoperative planning was a target bone resection of 10 to 15 mm including osteophytes and the lateral facet of the patella. Arthroscopic anterolateral and anterior superolateral portals were used to achieve the desired resection. An arthroscopic technique allows a direct view of the osteoarthritic bone for removal and permits intraoperative dynamic evaluation, which allows the surgeon to finetune the bone resection and obtain optimal patellar tracking. Avoiding arthrotomy could reduce morbidity and allows a rapid postoperative rehabilitation.

International audience; Vulnerable carotid atherosclerotic plaques are characterised by several risk factors, such as inflammation, neovascularization and intraplaque haemorrhage (IPH). Vulnerable plaques can lead to ischemic events such as stroke. Many studies reported a relationship between IPH, plaque rupture, and ischemic stroke. Histology is the gold standard to evaluate IPH, but it required carotid endarterectomy (CEA) surgery to collect the tissue sample. In this context, several imaging methods can be used as a non-invasive way to evaluate plaque vulnerability and detect IPH. Most imaging studies showed that IPH is associated with plaque vulnerability and stroke, with magnetic resonance imaging (MRI) being the most sensitive and specific to detect IPH as a predictor of ischemic events. These conclusions are however still debated because of the limited number of patients included in these studies; further studies are required to better assess risks associated with different IPH stages. Moreover, IPH is implicated in plaque vulnerability with other risk factors which need to be considered to predict ischemic risk. In addition, MRI sequences standardization is required to compare results from different studies and agree on biomarkers that need to be considered to predict plaque rupture. In these circumstances, IPH detection by MRI could be an efficient clinical method to predict stroke. The goal of this review article is to first describe the pathophysiological process responsible for IPH, its histological detection in carotid plaques and its correlation with plaque rupture. The second part will discuss the benefits and limitations of imaging the carotid plaque, and finally the clinical interest of imaging IPH to predict plaque rupture, focusing on MRI-IPH.

Background To determine the influence of anterolateral ligament reconstruction (ALLR) on knee constraint through the analysis of knee abduction (valgus) moment when the knee is subjected to external translational (anterior) or rotational (internal) loads. Methods A knee computer model simulated from a three-dimensional computed tomography scan of healthy male was implemented for this study. Three groups were designed: (1) intact knee, (2) combined Anterior Cruciate Ligament (ACL) and Antero-Lateral Complex (ALC) deficient knee, and (3) combined ACL and Antero- lateral Ligament (ALL) reconstructed knee. The reconstructed knee group was subdivided into four groups according to attachment of reconstructed anterolateral ligament to the femoral epicondyle. Each group of simulated knees was placed at 0°, 10°, 20°, 30°, 40° and 50° of knee flexion. For each position an external anterior (drawer) 90-N force or a five-newton meter internal rotation moment was applied to the tibia. The interaction effect between the group of knees and knee flexion angle (0–50°) on knee kinematics and knee abduction moment under external loads was tested. Results When reconstructed knees were subjected to a 90-N anterior force or a five-newton meter internal rotation moment there was significant reduction in anterior translation and internal rotation compared with deficient knees. Only the ALLR procedure using posterior and proximal femoral attachment sites for graft fixation combined with ACL reconstruction allowed similar mechanical behavior to that observed in the intact knee. Conclusions Combined ACL and ALLR using a minimally invasive method in an anatomically reproducible manner prevents excessive anterior translation and internal rotation. Using postero-proximal femoral attachment tunnel for reconstruction of ALL does not produce overconstraint of the lateral tibiofemoral compartment.

Resume Introduction Le basketball est un sport a risque de blessures, notamment par les caracteristiques physiques des joueurs et les contraintes techniques inherentes a cette activite. Dans une strategie de prevention des blessures, nous avons effectue une revue systematique de la litterature, axee sur l’epidemiologie des lesions liees a la pratique de ce sport. Methode Cinq bases de donnees ont ete utilisees : Pubmed, Scopus, Web of Science, SportDiscus et Cochrane Library. Ont ete incluses les etudes publiees en anglais ayant recueilli toutes les blessures liees a la pratique du basketball, detaillant le nombre de sujets et de blessures et une donnee d’exposition en heures de pratique ou en athlete-expose. Resultats Sur les 3699 articles initialement retrouves avec les mots cles, 21 ont ete inclus dans cette revue systematique, regroupant 46504 basketteurs et 20175 blessures. L’incidence totale des blessures etait de 13,0 blessures/1000AE et 5,7 blessures/1000 heures de pratique. Le membre inferieur etait la localisation la plus touchee (64 % des blessures), les entorses etaient le type de blessure majoritaire (39 % des blessures), principalement au niveau de la cheville (16 %). Ces blessures entrainaient dans 74 % des cas un arret de pratique inferieur a 8 jours. Les hommes, les matchs, les joueurs de plus de 20 ans, et les professionnels etaient plus a risque de blessures. Les lesions par contact dominaient (64 %). Conclusion Le basketball semble donc clairement un sport a risque avec une incidence elevee de blessures. Des mesures de prevention sont necessaires et doivent etre mises en place, particulierement au niveau du membre inferieur afin de limiter le risque d’entorses et de lesions musculaires.

BACKGROUND There is now ample evidence that motor imagery contributes to enhance motor learning and promote motor recovery in patients with motor disorders. Whether motor imagery practice is likely to facilitate mobility in patients suffering from knee osteoarthritis, at 6-months after total knee arthroplasty, remains unknown. AIM This trial was designed to evaluate the therapeutic effectiveness of implementing motor imagery into the classical course of physical therapy at 6-months after total knee arthroplasty. DESIGN Randomized controlled trial. POPULATION Twenty-four patients with unilateral total knee arthroplasty were assigned to a motor imagery or control group in a test-retest procedure, following a rehabilitation program as outpatients. METHODS During both the pre- and post-test, a set of strength and functional mobility measures were assessed: quadriceps strength, peak knee flexion during the swing phase, performance at the timed up and go test, stair climbing test, and 6-minute walk test, and finally Oxford knee score. In addition to a common physical therapy program, the motor imagery group practiced additional motor imagery exercises, while participants of the control group were subjected to a period of neutral activities for an equivalent amount of time. RESULTS Data provided evidence that motor imagery enhanced the quadriceps muscle strength of the operated knee (F (1, 22)=10.36, P=0.003), improved the peak knee flexion during the swing phase (F (1, 22)=31.52, P

Velocity strength training requires exercise modalities that allow athletes to reach very high movement velocity, which is limited during vertical movements involving body weight. Purpose: To quantify the mechanical outputs developed during horizontal squat jumps (HSJs), notably the movement velocity, in comparison with vertical squat jumps (SJs) with and without loads. Methods: Thirteen healthy male athletes performed SJs without additional loads (SJ0) and with a load of ∼60% of body mass (SJ60), and during HSJs performed lying on a roller device with (assisted HSJ [AHSJ]) and without (HSJ) rubber-band assistance. Instantaneous lower-limb extension velocity, force, and power output were measured and averaged over the push-off phase. Results: The force was significantly higher during SJ60 than during SJ0, which was higher than during HSJ and AHSJ. Extension velocity was significantly different across all conditions, with 0.86 (0.07), 1.29 (0.10), 1.59 (0.19), and 1.83 (0.19) m·s−1 for SJ60, SJ0, HSJ, and AHSJ conditions, respectively. Differences in force and velocity values between SJ0 and the other conditions were large to extremely large. Differences were observed in power values only between SJ60 and SJ0, SJ60 and AHSJ, and SJ0 and HSJ. Conclusions: HSJ modalities allow athletes to reach very to extremely largely greater lower-limb extension velocities (HSJ +24.0% [16%], AHSJ +42.8% [17.4%]) compared to those achieved during SJ0. HSJ and AHSJ modalities are inexpensive and practical modalities to train limb-extension velocity capabilities, that is, the ability of the neuromuscular system to produce force at high contraction velocities.

Summary Background Corticosteroids (CS) with or without adjuvant immunosuppressant agents are standard treatment for pemphigus vulgaris (PV). The efficacy of adjuvant therapies in minimizing steroid‐related adverse events (AEs) is unproven. Objectives To utilize data collected in a French investigator‐initiated, phase III, open‐label, randomized controlled trial to demonstrate the efficacy and safety of rituximab and seek approval for its use in PV. Methods This was an independently conducted post hoc analysis of the moderate‐to‐severe PV subset enrolled in the Ritux 3 study. Patients were randomized to rituximab plus 0·5 or 1·0 mg kg−1 per day prednisone tapered over 3 or 6 months, or 1·0 or 1·5 mg kg−1 per day prednisone alone tapered over 12 or 18 months, respectively (according to disease severity). The primary end point was complete remission at month 24 without CS (CRoff) for ≥ 2 months, and 24‐month efficacy and safety results were also reported. Results At month 24, 34 of 38 patients (90%) on rituximab plus prednisone achieved CRoff ≥ 2 months vs. 10 of 36 patients (28%) on prednisone alone. Median total cumulative prednisone dose was 5800 mg in the rituximab plus prednisone arm vs. 20 520 mg for prednisone alone. Eight of 36 patients (22%) who received prednisone alone withdrew from treatment owing to AEs; one rituximab‐plus‐prednisone patient withdrew due to pregnancy. Overall, 24 of 36 patients (67%) on prednisone alone experienced a grade 3/4 CS‐related AE vs. 13 of 38 patients (34%) on rituximab plus prednisone. Conclusions In patients with moderate‐to‐severe PV, rituximab plus short‐term prednisone was more effective than prednisone alone. Patients treated with rituximab had less CS exposure and were less likely to experience severe or life‐threatening CS‐related AEs. What's already known about this topic? Pemphigus vulgaris (PV) is the most common type of pemphigus.Corticosteroids, a standard first‐line treatment for PV, have significant side‐effects.Although their effects are unproven, adjuvant corticosteroid‐sparing agents are routinely used to minimize steroid exposure and corticosteroid‐related side‐effects.There is evidence that the anti‐CD20 antibody rituximab is effective in the treatment of patients with severe recalcitrant pemphigus and in patients with newly diagnosed pemphigus. What does this study add? This study provides a more detailed analysis of patients with PV enrolled in an investigator‐initiated trial.Rituximab plus prednisone had a steroid‐sparing effect and more patients achieved complete remission off prednisone.Fewer patients experienced grade 3 or grade 4 steroid‐related adverse events than those on prednisone alone.This collaboration between academia and industry, utilizing independent post hoc analyses, led to regulatory authority approvals of rituximab in moderate‐to‐severe PV., Linked Comment: Scorer et al. Br J Dermatol 2020; 182:1078–1079.

Perceived exertion is an important self-limiting factor influencing functional capacity in patients with sickle cell anemia (SCA). Exercise-related hemoglobin desaturation (EHD) may occur during a six-minute walking test (6MWT) and could influence the perceived rate of exertion. The aims of this study were (1) to compare the 6MWT responses (heart rate, perceived rate of exertion, and distance covered) between SCA children with and without EHD, and (2) to test the associations between EHD and several biological/physiological parameters. Nine of 51 SCA children (18%) at steady state (mean age 11.9 &plusmn, 3.8 years) exhibited EHD at the end of the 6MWT. The rate of perceived exertion increased with exercise in the two groups, but reached higher values in the EHD group. Heart rate and performance during the 6MWT did not differ between the two groups. The magnitude of change in SpO2 during the 6MWT was independently associated with the red blood cell (RBC) deformability and RBC aggregates strength. This study demonstrates that SCA children with EHD during a 6MWT have a higher rate of perceived exertion than non-EHD children despite a similar physiological demand, and that abnormal RBC rheology determinants appear to be significant contributors.

OBJECTIVE Long before clinical complications of type 1 diabetes (T1D) develop, oxygen supply and use can be altered during activities of daily life. We examined in patients with uncomplicated T1D all steps of the oxygen pathway, from the lungs to the mitochondria, using an integrative ex vivo (muscle biopsies) and in vivo (during exercise) approach. RESEARCH DESIGN AND METHODS We compared 16 adults with T1D with 16 strictly matched healthy control subjects. We assessed lung diffusion capacity for carbon monoxide and nitric oxide, exercise-induced changes in arterial O2 content (SaO2, PaO2, hemoglobin), muscle blood volume, and O2 extraction (via near-infrared spectroscopy). We analyzed blood samples for metabolic and hormonal vasoactive moieties and factors that are able to shift the O2-hemoglobin dissociation curve. Mitochondrial oxidative capacities were assessed in permeabilized vastus lateralis muscle fibers. RESULTS Lung diffusion capacity and arterial O2 transport were normal in patients with T1D. However, those patients displayed blunted exercise-induced increases in muscle blood volume, despite higher serum insulin, and in O2 extraction, despite higher erythrocyte 2,3-diphosphoglycerate. Although complex I– and complex II–supported mitochondrial respirations were unaltered, complex IV capacity (relative to complex I capacity) was impaired in patients with T1D, and this was even more apparent in those with long-standing diabetes and high HbA1c. O2max was lower in patients with T1D than in the control subjects. CONCLUSIONS Early defects in microvascular delivery of blood to skeletal muscle and in complex IV capacity in the mitochondrial respiratory chain may negatively impact aerobic fitness. These findings are clinically relevant considering the main role of skeletal muscle oxidation in whole-body glucose disposal.

Blood viscosity is an important determinant of local flow characteristics, which exhibits shear thinning behavior: it decreases exponentially with increasing shear rates. Both hematocrit and plasma viscosity influence blood viscosity. The shear thinning property of blood is mainly attributed to red blood cell (RBC) rheological properties. RBC aggregation occurs at low shear rates, and increases blood viscosity and depends on both cellular (RBC aggregability) and plasma factors. Blood flow in the microcirculation is highly dependent on the ability of RBC to deform, but RBC deformability also affects blood flow in the macrocirculation since a loss of deformability causes a rise in blood viscosity. Indeed, any changes in one or several of these parameters may affect blood viscosity differently. Poiseuille’s Law predicts that any increase in blood viscosity should cause a rise in vascular resistance. However, blood viscosity, through its effects on wall shear stress, is a key modulator of nitric oxide (NO) production by the endothelial NO-synthase. Indeed, any increase in blood viscosity should promote vasodilation. This is the case in healthy individuals when vascular function is intact and able to adapt to blood rheological strains. However, in sickle cell disease (SCD) vascular function is impaired. In this context, any increase in blood viscosity can promote vaso-occlusive like events. We previously showed that sickle cell patients with high blood viscosity usually have more frequent vaso-occlusive crises than those with low blood viscosity. However, while the deformability of RBC decreases during acute vaso-occlusive events in SCD, patients with the highest RBC deformability at steady-state have a higher risk of developing frequent painful vaso-occlusive crises. This paradox seems to be due to the fact that in SCD RBC with the highest deformability are also the most adherent, which would trigger vaso-occlusion. While acute, intense exercise may increase blood viscosity in healthy individuals, recent works conducted in sickle cell patients have shown that light cycling exercise did not cause dramatic changes in blood rheology. Moreover, regular physical exercise has been shown to decrease blood viscosity in sickle cell mice, which could be beneficial for adequate blood flow and tissue perfusion.

Action observation (AO) alone or combined with motor imagery (AO + MI) has been shown to engage the motor system. While recent findings support the potential relevance of both techniques to enhance muscle function, this issue has received limited scientific scrutiny. In the present study, we implemented a counterbalanced conditions design where 21 participants performed 10 maximal isometric contractions (12-s duration) of elbow flexor muscles against a force platform. During the inter-trial rest periods, participants completed i) AO of the same task performed by an expert athlete, ii) AO + MI, i.e. observation of an expert athlete while concurrently imagining oneself performing the same task, and iii) watching passively a video documentary about basketball shooting (Control). During force trials, we recorded the total force and integrated electromyograms from the biceps brachii and anterior deltoideus. We also measured skin conductance from two finger electrodes as an index of sympathetic nervous system activity. Both AO and AO + MI outperformed the Control condition in terms of total force (2.79–3.68%, p

International audience; PURPOSE:This study aimed to examine the extent to which the classical physiological variables of endurance running performance (maximal oxygen uptake (V˙O2max), %V˙O2max at ventilatory threshold (VT), and running economy (RE)) but also muscle strength factors contribute to short trail running (TR) performance.METHODS:A homogeneous group of nine highly trained trail runners performed an official TR race (27 km) and laboratory-based sessions to determine V˙O2max, %V˙O2max at VT, level RE (RE0%) and RE on a +10% slope, maximal voluntary concentric and eccentric knee extension torques, local endurance assessed by a fatigue index (FI), and a time to exhaustion at 87.5% of the velocity associated with V˙O2max. A simple regression method and commonality analysis identifying unique and common coefficients of each independent variable were used to determine the best predictors for the TR race time (dependent variable).RESULTS:Pearson correlations showed that FI and V˙O2max had the highest correlations (r = 0.91 and r = -0.76, respectively) with TR performance. The other selected variables were not significantly correlated with TR performance. The analysis of unique and common coefficients of relative V˙O2max, %V˙O2max at VT, and RE0% provides a low prediction of TR performance (R = 0.48). However, adding FI and RE on a +10% slope (instead of RE0%) markedly improved the predictive power of the model (R = 0.98). FI and V˙O2max showed the highest unique (49.8% and 20.4% of total effect, respectively) and common (26.9% of total effect) contributions to the regression equation.CONCLUSIONS:The classic endurance running model does not allow for meaningful prediction of short TR performance. Incorporating more specific factors into TR such as local endurance and gradient-specific RE testing procedures should be considered to better characterize short TR performance.

The aim of this study was to measure physical and functional outcomes during the acute postoperative recovery in patients who underwent total knee arthroplasty. Motor imagery has been shown to decrease pain and promote functional recovery after both neurological and peripheral injuries. Yet, whether motor imagery can be included as an adjunct effective method into physical therapy programs following total knee arthroplasty remains a working hypothesis that we aim to test in a pilot study.Twenty volunteers were randomly assigned to either a motor imagery or a control group. Pain, range of motion, knee girth as well as quadriceps strength and Timed Up and Go Test time were the dependent variables during pre-test and post-test.The motor imagery group exhibited larger decrease of ipsilateral pain and knee girth, a slightly different evolution of range of motion and an increase of ipsilateral quadriceps strength compared to the control group. No effects of motor imagery on Timed Up and Go Test scores were observed.Implementing motor imagery practice into the course of physical therapy enhanced various physical outcomes during acute postoperative recovery after total knee arthroplasty. According to this pilot study, motor imagery might be relevant to promote motor relearning and recovery after total knee arthroplasty.Partial effect-sizes should be conducted in the future. Implications for rehabilitation Adding motor imagery to physical therapy sessions during the acute period following total knee arthroplasty: • Enhances quadriceps strength. • Alleviates pain. • Enhances range of motion. • Does not have any effect on basic functional mobility. • Does not have any effect on knee girth.

International audience; The aim of the present study was to test the effects of hydroxyurea (HU) therapy on clinical, hematological and hemorheological parameters in adult patients with sickle cell anemia (SCA). Hematological and hemorheological parameters were measured in 28 SCA patients before HU therapy (i.e., baseline) and at 6, 12 and 24 months of treatment. RBC deformability was determined by ektacytometry at 30 Pa. RBC aggregation properties were investigated by light-backscatter method. Blood viscosity was measured at 225 s-1 by a cone-plate viscometer. The rates of vaso-occlusive crises and acute chest syndrome were lower at 1 and 2 years of HU therapy compared to baseline. The proportion of patients with leg ulcers tended to decrease after 2 years of treatment. Hemoglobin oxygen saturation improved with HU therapy. HU therapy induced a decrease of platelet and white blood cell counts and a rise in fetal hemoglobin level and mean cell volume. While hemoglobin concentrations increased under HU, blood viscosity remained unchanged all along the study. RBC deformability increased over baseline values at 6 months of HU therapy and continued to rise until the end of the follow-up period. In conclusion, the improvement in RBC deformability probably compensates the increase of hemoglobin on blood viscosity and participates to the improvement of the clinical status of patients.

The objective of this study was to investigate the pressure applied by superimposed bandages and to compare it with the pressure applied by single-component bandages.Six different bandages, composed of one elastic bandage, one nonelastic bandage, or both, were applied in a spiral pattern on both legs of 25 patients at risk of venous thrombosis as a consequence of central or peripheral motor deficiency. Pressure was measured at four measurement points on the leg (B1 and C on the medial and lateral sides of the leg) and in three positions: supine, sitting, and standing.The two single bandages applied similar pressure in the supine position. Their superimposition showed different pressure levels (P .05) but similar static stiffness index, depending on the order in which the bandage components were applied on the leg. The highest interface pressure was measured at point B1 on the medial side of the leg. This point also showed the highest pressure increase from supine to standing position. The pressure applied by the superimposition of two bandages was computed as a linear combination of the pressure applied by each single component (with a constant term set to 0). However, this linear combination did not properly fit the experimental pressure measurements.The order of bandage application showed a significant impact on interface pressure. However, the poor correlation between the pressure applied by each bandage component and the pressure resulting from their superimposition underlined the poor understanding of interface pressure generated by the superimposition of compression bandages and should lead to further investigations.

Dual mobility was introduced by Pr. G. Bousquet to improve the dislocation risk of total hip arthroplasty (THR). The wear mechanisms of this implant remain to be understood. Could enhanced explant wear analysis explain liner wear behaviour?Sixty-six explanted liners were selected. Non-destructive 3D scanning and heat colour treatment allowed reporting wear patterns on both convex and concave sides of the liners.For many liners, liner convexity wear was found to be homogeneous, and linked to a longer implantation time. A few liners had signs of blocking of the convexity, leading to excessive internal damage. Intra prosthetic dislocations were found to only have internal circular wear without liner penetration.Heat colour treatment showed its effectiveness for highlighting wear patterns. Optimal convexity mobility seemed to be leading to a longer implantation time, with decreased contact stresses on concavity. The retentive rim should have a distinct wear analysis.

Blood rheology and hemodynamic parameters have never been explored together during acclimatization to altitude. This study aimed to investigate changes in blood rheology parameters and pulmonary hemodynamics during the first days of real moderate altitude exposure.Seventeen athletes were tested at sea-level, 20 hours after their arrival at 2,400 meters of altitude (H1) and five days later (H2). Blood was sampled to analyze red blood cell (RBC) aggregation, blood viscosity and hematocrit. Pulmonary arterial pressure (PAP), pulmonary capillary pressure (Pcap) and pulmonary vascular resistance (PVR) were assessed by echocardiography.We observed a rise in hematocrit, blood viscosity, RBC aggregation, PAP, Pcap and PVR between sea-level and H1. In H2, RBC aggregation, hematocrit, PAP, Pcap and PVR remained different compared to sea-level and no difference was observed between H1 and H2. Blood viscosity decreased in H2 and returned to sea-level values.Our results suggest that hemoconcentration occurring within the first hours of altitude exposure increased blood viscosity, which contributed to the changes in pulmonary hemodynamic. When blood viscosity decreased in H2, no change occurred in pulmonary hemodynamic parameters suggesting that hypoxic pulmonary vasoconstriction was still present. The elevated RBC aggregation observed after in H2 could participate in the increase of Pcap.

Sickle cell anaemia (SCA) is characterized by reduced red blood cell (RBC) deformability and nitric oxide (NO) bioavailability. The aim of the study was to investigate whether exercise might affect these parameters in SCA. SCA patients and healthy controls (AA) performed an acute submaximal exercise test until subjects reached the first ventilatory threshold (VT 1). Blood was sampled at rest and at VT 1. At rest, free haemoglobin level was higher and RBC count, haemoglobin and haematocrit were lower in SCA compared to AA. RBC deformability was lower in SCA. Exercise had no effect on the tested parameters. RBC NO level was higher in SCA compared to AA at rest and significantly decreased after exercise in SCA. This might be related to a reduction in RBC-NO synthase (RBC-NOS) activation which was only observed in SCA after exercise. Free radical levels were higher in SCA at rest but concentration was not affected by exercise. Marker for lipid peroxidation and antioxidative capacity were similar in SCA and AA and not affected by exercise. In conclusion, a single acute submaximal bout of exercise has no deleterious effects on RBC deformability or oxidative stress markers in SCA, and seems to modulate RBC-NOS signalling pathway.

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In the bilateral Nordic hamstring exercise (NHE), hamstrings operate at relatively short lengths, which may limit the efficacy of the NHE in hamstring injury prevention.To examine knee flexion torque and biceps femoris long head (BFLH) and semitendinosus (ST) high-density electromyography (EMG) activity during the unilateral and bilateral NHE, performed with either neutral (NHE0) or 90°-flexed (NHE90) hips.In this laboratory study, exercises were performed on a novel device at the eccentric 1-repetition maximum load defined for 90° to 15° of knee range of motion. Torque and EMG signals normalized to maximal voluntary isometric activity were compared in different phases of the exercises with statistical parametric mapping.The EMG levels were lower in NHE90 than in NHE0, mainly in the second half of the movement. Knee flexor eccentric torque was higher in NHE90 than in NHE0 from the beginning to 87% of the bilateral movement, and over the entire unilateral movement. In NHE0, ST activity compared to BFLH activity was higher during the initial movement phase and lower when the movement was close to knee extension. Torque and EMG activity were generally similar in the bilateral and unilateral modes.If performed with neutral hips, the NHE selectively activates the BFLH near full knee extension. Performing the NHE with hips flexed to 90° is preferable when higher passive torque and ST selectivity are targeted at a longer muscle length. Performing these exercises unilaterally could help train each limb separately, with similar torque and EMG output to those of the bilateral conditions.

International audience; Magnesium (Mg2+) is critical for a number of biological processes and 25% body Mg2+ is located in the skeletal muscle. Mg2+ transport and homeostasis systems (MgTHs) regulate intracellular Mg2+ concentration and muscle MgTHs are thus related to whole body Mg2+ homeostasis. Nonetheless, few studies have investigated the regulation of muscle MgTHs under (patho)physiological conditions. Herein, we assessed the relationship between the expression of MgTHs genes (Trpm6, Trpm7, Magt1, Mrs2, Cnnm1-4, Slc41a1-3) and relevant pathways in human sarcopenia, which is one of the most dramatic physiologic changes affecting the human body. Transcriptomic data were compared between young adult (YO, 22 y, n = 11) and old (EL, 73 y, n = 13) men from the PROOF cohort. MgTH mRNA levels did not change with aging, with the exception of a slight decrease for Slc41a3. Nevertheless, interindividual variations of mRNA levels revealed strong correlations between MgTHs in the YO group, while few were maintained in the EL muscle. Moreover, in the YO muscle, different clusters of MgTH mRNAs strongly correlated with divers physiological (BMI, blood pressure) and muscle characteristics (intramyocellular droplets, capillarization); however, most correlations changed or disappeared in the EL muscle. Further investigations of the whole transcriptome identified several sets of mRNAs correlated with defined MgTHs. There again was a sharp difference between YO and EL muscles, as the number of mRNAs correlated with MgTHs strongly decreased with aging. Gene ontology analyses of these sets of correlated mRNAs revealed 6 biological processes common to YO and EL, 3 specific to the YO (RNA processing, translation, respiration), and 2 (regulation of catabolic process, Wnt signaling) to the EL muscle. Overall, these observations lead to questions about potential resilience to muscle Mg2+ homeostasis in the elderly.

International audience; BACKGROUND: Our objective was to investigate the combined and differential effects of alpha-thalassemia -3.7 kb deletion and HbF-promoting quantitative trait loci (HbF-QTL) in Senegalese hydroxyurea (HU)-free children and young adults with sickle cell anemia (SCA).PROCEDURE: Steady-state biological parameters and vaso-occlusive crises (VOC) requiring emergency admission were recorded over a 2-year period in 301 children with SCA. The age of the first hospitalized VOC was also recorded. These data were correlated with the alpha-globin and HbF-QTL genotypes. For the latter, three different genetic loci were studied (XmnI, rs7482144; BCL11A, rs1427407; and the HBS1L-MYB region, rs28384513) and a composite score was calculated, ranging from zero (none of these three polymorphisms) to six (all three polymorphisms at the homozygous state).RESULTS: A positive clinical impact of the HbF-QTL score on VOC rate, HbF, leucocytes, and C-reactive protein levels was observed only for patients without alpha-thalassemia deletion. Conversely, combination of homozygous -3.7 kb deletion with three to six HbF-QTL was associated with a higher VOC rate. The age of the first hospitalized VOC was delayed for patients with one or two alpha-thalassemia deletions and at least two HbF-QTL.CONCLUSION: Alpha-thalassemia -3.7 kb deletion and HbF-QTL are modulating factors of SCA clinical severity that interact with each other. They should be studied and interpreted together and not separately, at least in HU-free children.

During high intensity exercise, metabosensitive muscle afferents are thought to inhibit the motor drive command to restrict the level of peripheral fatigue to an individual’s critical threshold. No evidence exists of an individual relationship between peripheral fatigue and the decrease in voluntary activation reached after prolonged all-out exercise. Moreover, there is no explanation for the previously reported large decrease in voluntary activation despite low metabolic stress during high force contractions. Thirteen active men completed two maximal intensity isokinetic knee extension tests (160 contractions) under conditions of low force – high velocity and high force – low velocity. Neuromuscular testing including maximal torque, evoked torque and voluntary activation, was done every 20 contractions. The exponential modeling of these variables over time allowed us to predict the stable state (asymptote) and the rate of decrease (curvature constant). For both high and low force contractions the evoked torque and voluntary activation asymptotes were negatively correlated (R2 = 0.49 and R2 = 0.46, respectively). The evoked torque asymptotes of the high and low force conditions were positively correlated (R2 = 0.49). For the high force contractions, the evoked torque and voluntary activation curvature constant were negatively correlated (R2 = 0.43). These results support the idea that a restrained central motor drive keeps peripheral fatigue under this threshold. Furthermore, an individual would show similar fatigue sensibility regardless of the force generated. These data also suggest that the decrease in voluntary activation might not have been triggered by peripheral perturbations during the first high force contractions.

Background To assess anatomic risk factors for meniscal lesions in association with acute ACL rupture. The primary hypothesis was that tibiofemoral anatomic measures will be different in those with and without concomitant meniscus tears. Methods A retrospective review of patients who underwent acute ACL reconstruction in the department was performed. All patients underwent a postoperative CT scan. The concavity and/or convexity on the femur and the tibia were measured by two blinded observers on the sagittal plane with different ratios, and these measures were compared in patients with and without meniscus tears in each compartment. Intra- and inter-rater reliabilities were assessed. Results Four hundred twelve patients (268 males and 144 females) were included from October 2012 to February 2015. One hundred sixty-seven patients had a medial meniscal tear (119 males/48 females), and 100 had a lateral meniscal tear (80 males/20 females). The mean time from injury to surgery was 3 months. The average ICC for all measurements was 0.87 (range 0.82–0.98) indicating good reliability. The medial femoral condyle was noted to be significantly longer than the medial tibial plateau in the sagittal plane in patients with a medial meniscal tear (p = 0.04), and the lateral femoral condyle was noted to be significantly longer than the lateral tibial plateau in the sagittal plane in patients with a lateral meniscal tear (p

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Sickle cell disease (SCD) is associated with chronic activation of coagulation and an increased risk of venous thromboembolism. Erythrocyte sickling, the primary pathologic event in SCD, results in dramatic morphological changes in red blood cells (RBCs) because of polymerization of the abnormal hemoglobin. We used a mouse model of SCD and blood samples from sickle patients to determine if these changes affect the structure, properties, and dynamics of sickle clot formation. Sickling of RBCs and a significant increase in fibrin deposition were observed in venous thrombi formed in sickle mice. During ex vivo clot contraction, the number of RBCs extruded from sickle whole blood clots was significantly reduced compared with the number released from sickle cell trait and nonsickle clots in both mice and humans. Entrapment of sickled RBCs was largely factor XIIIa–independent and entirely mediated by the platelet-free cellular fraction of sickle blood. Inhibition of phosphatidylserine, but not administration of antisickling compounds, increased the number of RBCs released from sickle clots. Interestingly, whole blood, but not plasma clots from SCD patients, was more resistant to fibrinolysis, indicating that the cellular fraction of blood mediates resistance to tissue plasminogen activator. Sickle trait whole blood clots demonstrated an intermediate phenotype in response to tissue plasminogen activator. RBC exchange in SCD patients had a long-lasting effect on normalizing whole blood clot contraction. Furthermore, RBC exchange transiently reversed resistance of whole blood sickle clots to fibrinolysis, in part by decreasing platelet-derived PAI-1. These properties of sickle clots may explain the increased risk of venous thromboembolism observed in SCD.

Resume Introduction La mise en place d’une prothese totale de hanche (PTH), dans les suites d’echec d’osteosynthese de fracture de l’extremite superieure du femur, est associee a un risque eleve de luxation prothetique. Notre hypothese etait que l’utilisation d’une cupule double mobilite (DM), permettait dans ce contexte specifique de diminuer le risque d’instabilite postoperatoire. Materiel et methodes Il s’agissait d’une serie retrospective et continue, incluant 33 patients operes d’une PTH avec une cupule DM suite a un echec d’osteosynthese d’une fracture de l’extremite superieure du femur. Une evaluation clinique comportant l’analyse des scores HHS et PM, ainsi qu’une analyse radiologique, ont ete realisees en preoperatoire et au dernier recul. Le critere de jugement principal etait la survenue d’une luxation prothetique. Resultats Au dernier recul (44 ± 24 mois), 7 patients etaient decedes et aucun n’a ete perdu de vue. Un seul cas de luxation a ete reporte (3 %). Au dernier recul, les scores cliniques moyens de PMA et de HHS, respectivement de 14,8 et de 80, etaient significativement ameliores par rapport aux scores preoperatoires. Aucun descellement aseptique n’a ete rapporte. Conclusion L’utilisation de cupules DM, dans le cadre de la mise en place d’une PTH apres echec d’osteosynthese de l’extremite proximale du femur, permet de diminuer le risque de luxation prothetique. Son utilisation peut donc etre recommandee dans cette indication a haut risque d’instabilite post operatoire.