Quels tests de terrain pour le suivi de la performance athlétique en sport collectif ?

Introduction

To monitor athletic performance throughout a team-sport season, strength and conditioning coaches are used to program various field tests that evaluate physiological variables predictive of performance in their activity. Nevertheless, performing all these field tests is time consuming and not well appropriated for frequent monitoring.

Synthesis of the facts

The present study investigated whether a single test can be used as a surrogate of overall team athletic performance.

Conclusion

It appears that the 30-15 Intermittent Fitness Test and a repeated sprint ability test, but not explosive power of lower limb or sprinting tests, are sensitive enough to differentiate different performance levels throughout the season.     

Sexe des joueurs et blessures en handball : influence de l’arbitrage ?

Introduction

The aim of this study was to examine whether refereeing may be evocated to explain why male handball players get injured more often than female players.

Synthesis of the facts

A total of 90 handball matches, both men's and women's, were observed focusing on transgression play against players in possession of the ball and the resulting refereeing decisions. The aggressive behavior and refereeing differ according to the sex of the players.

Conclusion

Female players are refereed more severely which may help to explain why they are less aggressive and get injured less frequently than their male counterparts.     

Resonancia magnética de perfusión en astrocitomas de alto grado: el volumen sanguíneo cerebral,la altura del pico y el porcentaje de recuperación de intensidad de señal ¿pueden discriminar entre progresión y seudoprogresión?

Objectives

To study the usefulness of common MRI perfusion parameters for identifying pseudoprogression in high grade astrocytomas.

Material and methods

This retrospective case-control study compared the relative cerebral blood volume (rCBV), the relative percentage of signal intensity recovery (rPSR), and the relative peak height (rPH) recorded in a sample of 17 cases of anaplastic astrocytomas and gliomas considered to be undergoing pseudoprogression by biopsy or follow-up with those recorded in a sample of histologically similar tumors that were treated and considered to be undergoing progression by histologic study or follow-up. We evaluated the accuracy of these parameters and the correlations among them. Statistical significance was set at P<.05.

Results

The rCBV, rPSR, and rPH were significantly different between the two groups (P=.001). The cutoff values rPH=1.37, rCBV=0.9, and rPSR=99% yielded sensitivity (S)=88% and specificity (Sp)=82.2% for rPH, S=100% and Sp=100% for rCBV, and S=100% and Sp=70.6% for rPSR, respectively. We found negative correlations between rPRS and rPH (−0.76) and between rPRS and rCBV (−0.81) and a high positive correlation between rPH and rCBV (0.87).

Conclusion

The variables rPH and rCBV were useful for differentiating between pseudoprogression and true progression in our sample. The variable rPRS was also very sensitive, although the overlap in the values between samples make it less useful a priori.     

Conocimientos en materia de radioprotección en radiólogos del noroeste de España

Objectives

To estimate radiologist? level of knowledge of and their implication in radioprotection.

Formación online en Radiología en tiempos de COVID

The COVID-19 pandemic has changed the methods used for teaching radiology in medical schools, residency programs, and continuing medical education. The need to continue training in radiology in a situation requiring physical distancing has led to the massive use of online methods, and this is where internet has provided a solution to mitigate the problem. This paper aims to present a series of useful, freely accessible resources that share the #FOAMRad philosophy for online training in radiology during the COVID-19 pandemic.     

L’étude des forces de réaction au sol peut-elle être un indicateur de la stabilité de la chaussure lors de la locomotion ?

Objective

The aim of this study was to determine the influence of ground reaction forces on the footwear stability.

Material and methods

Twelve healthy men have walked on a treadmill ergometer ADAL with five different shoe models and in a barefoot condition. Here, the shoe called “shoe 1” is known for its capacity to stabilize the foot. Ground reaction forces (F_x, F_y, F_z) were recorded at constant speed (2, 4 and 6 km h⁻¹), and during transition phases (0 to 2, 0 to 4, 0 to 6 km h⁻¹). Two running conditions (8 km h⁻¹ at constant speed and 0 to 8 km h⁻¹ in transition) have completed this protocol. Then, each subject filled in a questionnaire to evaluate, for each shoe, different sensations: stability during walking and running, foot support, heightening of the rearfoot, width of shoe at the heel, general comfort, cushioning. At last, different geometrical parameters of each shoe were measured.

Results and discussion

The results show that, in all tested conditions (constant speed and transition phases, walking and running), medial force peaks are significantly more important in barefoot condition than all shod conditions, except for the shoe 1. As the barefoot condition is, according to the literature, the best condition of stability and as the shoe 1 is known for its capacity to stabilize the foot, these results could suggest that a better stability could be associated with more important medial force peaks.     

Plans d'expériences en carré latin pour l'analyse globale de la performance en ski de fond

Introduction – The aim of this study is to quantify the influence of the roughness and the waxing of the ski soles in the skating performance in cross country skiing.Methods and results – The experimental factors are the skier, the topography and the gliding wax; each one is declined in three methods. Nine tests – with variation of all the factors to each test – are defined using the technique of the experiment matrices structured in Latin Square. Each combination of the three factors is tested on a flat course of 200 m with recording of time on 30 m. The nine tests are repeated three times during a day. Twenty one days of tests are organized during one winter season. The results show a prevalent influence of the skier factor in the V1-skating performance compared to the topography and wax influence.Conclusion – In V1-skating, the expertise level of skier is preponderant; but on equal expertise level, the difference on the performance between a good and a bad choice of topography and waxing of the ski sole varies between 3 and 10% of the course time.     

Percepciones de estudiantes de Medicina sobre el impacto de la inteligencia artificial en radiología

ObjectivesTo analyze medical students’ perceptions of the impact of artificial intelligence in radiology.Material and methodsA structured questionnaire comprising 28 items organized into six sections was distributed to students of medicine in Spain in December 2019.ResultsA total of 341 students responded. Of these, 27 (7.9%) included radiology among their three main choices for specialization, and 51.9% considered that they clearly understood what artificial intelligence is. The overall rate of correct answers to the objective true-or-false questions about artificial intelligence was 70.7%. Whereas 75.9% expressed their disagreement with the hypothesis that artificial intelligence would replace radiologists, only 41.9% disagreed with the hypothesis that the demand for radiologists would decrease in the future. Only 36.7% expressed concerns about the role of artificial intelligence related to choosing radiology as a specialty. A greater proportion of students in the early years of medical school agreed with statements that radiologists accept artificial-intelligence-related technological changes and work with the industry to apply them as well as with statements about the need to include basic training about artificial intelligence in the medical school curriculum.ConclusionsThe students surveyed are aware of the impact of artificial intelligence in daily life, but not of the current debate about its potential applications in radiology. In general, they think that artificial intelligence will revolutionize radiology without having an alarming effect on the employability of radiologists. The students surveyed think that it is necessary to provide basic training about artificial intelligence in undergraduate medical school programs.     

Effet de l’intensité de course sur la force de poussée en rugby

Introduction. – The rugby is a discipline requiring, in the same time, strength qualities and a high aerobic capacity for repeating intense exercises over 2 × 40 min.Synthesis of the facts. – Fourteen rugby players performed a maximal progressive test of journey (running) then two sequences of 40 min, respectively, to 60% and 80% of HR_max, interrupted with pushes on a yoke with constraint gauges. At 80% HR_max, the mean scrummaging force (1466 ± 244 N) was lower (P < 0.05) than at 60% HR_max (1523 ± 266 N).Conclusion. – The qualities of specific force are directly affected by the intensity of running. Therefore, there is a need to optimize the aerobic potential notably for the players of the first line directly concerned by the fight.     

Comparación de una secuencia en 3D con eco de gradiente potenciada en T1 con 3 factores de reducción de imagen en paralelo diferentes,en apnea y respiración libre,utilizando una bobina de 32 canales a 1,5T. Estudio preliminar

PurposeTo investigate whether increasing temporal resolution with higher parallel imaging (PI) reduction factors (RF) in both breath-hold and free breathing approaches, using a non-contrast T1-weighted 3D gradient echo (GRE) sequence and a 32-channel phased array coil, permits diagnostic image quality, with potential application in patients unable to cooperate with breath-hold requirements.Materials and methodsThe 9 healthy subjects (5 females and 4 males; age range was 20-49, mean 36 yrs) were recruited. A 3D GRE MR imaging of the abdomen was performed on 1.5T MR system using a 32-element phased-array torso coil with PI RFs of 2, 4 and 6, breath hold and free breathing. Two reviewers retrospectively qualitatively evaluated all sequences for image quality, extent of artifacts, including motion, truncation, aliasing, pixel graininess and signal heterogeneity. The results were compared using Wilcoxon signed rank and a Bonferroni adjustment was applied for multiple comparisons.ResultsImage quality and extent of artifacts were better with breath hold than with free breathing acquisitions. The rate of artifacts increased with higher RF. The best quality was acquired with breath hold sequence using RF=2. RF=4 had lower but diagnostic rates (P=.004). The severity of artifacts, mainly pixel graininess (P=.004), rendered sequences with RF=6 non-diagnostic. All sequences were non-diagnostic in free breathing acquisitions.ConclusionBreath hold sequences with RF=2 had excellent quality and RF=4 had good quality and may be potentially used in partially cooperative patients. None of the sequences was considered diagnostic in free breathing acquisitions.     

Comparación de la calidad de imagen y dosis de radiación en angio-tomografía computarizada de arterias periféricas con 80 y 100 kV

ObjectiveTo compare the image quality and dose of radiation in two groups of patients undergoing CT angiography of the lower limbs, one with tube voltage of 80 kV and the other with tube voltage of 100 kV.Material and methodsWe performed CT angiography of the lower limbs in 60 patients with suspected peripheral arterial disease. Patients were randomly assigned to one of two groups; in one group, CT angiography was performed using a tube voltage of 80 kV, whereas in the other it was performed using 100 kV. The remaining acquisition parameters were the same in both groups. The images were analyzed by quantifying vascular density (VD) and noise (N) and by calculating the quotients density/noise (QVDN) and contrast/noise (QCN). Two radiologists working independently evaluated the subjective quality of the images. We calculated the estimated effective dose (EED) based on the dose-length product (DLP).ResultsIn the group studied at 80 kV, VD was significantly higher (462.5 UH ± 95.6 vs. 372 UH ± 100.9; P <. 001), QVDN was significantly higher (241.9 ± 48.1 vs. 194.3 ± 49.6; P < .001), and there were trends toward higher N (21.3 UH ± 13 vs. 16.3 UH ± 3.5; P = .098) and toward higher QCN (21.4 ± 12.1 vs. 22.9 ± 9.1; P = .15). No significant differences were found in the subjective quality of the images. The EED was significantly lower in the group studied at 80 kV (4.73 mSv ± 1.1 vs. 9.6 mSv ± 2.2; P <. 001).ConclusionUsing 80 kV instead of 100 kV for CT angiography of the lower limbs reduces the dose of radiation without affecting the diagnostic efficacy of the study.     

Manifestaciones extratorácicas de la COVID-19 en adultos y presentación de la enfermedad en niños

In March 2020, the World Health Organization declared a global pandemic of COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); epidemic conditions continue in nearly all countries today. Although the symptoms and imaging manifestations of COVID-19 predominantly involve the respiratory system, it is fundamental to know the manifestations of the disease and its possible complications in other organs to help in diagnosis and orient the prognosis. To improve the diagnostic process without increasing the risk of contagion unnecessarily, it is crucial to know when extrathoracic imaging tests are indicated and which tests are best in each situation. This paper aims to provide answers to these questions. To this end, we describe and illustrate the extrathoracic imaging manifestations of COVID-19 in adults as well as the entire spectrum of imaging findings in children.     

Facteurs limitants de la performance en haute altitude : opération Everest III,Comex'97

Objectives – Operation Everest III (Comex'97) was performed to evaluate the physiological, psychological and pathological mechanisms induced by a prolonged exposure to extreme altitude, up to 8,848 m (altitude of Mount Everest).Methods – Eight male subjects (23 to 37 years old) have been studied in normoxia, then, after 6 d of acclimatization at 4350 m, in a hypobaric chamber (Comex SA, Marseille) where they stayed 31 d, from 5000 m to 8848 m of simulated altitude. Eighteen protocols, from 14 scientific teams, have explored various aspects of acclimatization to extreme altitude.Results – The decrease in plasma volume is one of the factors involved in the reduction of physical performance, as witnessed by the 9% increase in VO_2max at 6000 m under infusion of 300 ml hydroxyethylamidon. Ventilatory and cardiac responses to hypoxia at exercise have an opposite trend, with an increase in ventilatory and a decrease in cardiac response. Autoregulation of cerebral circulation is altered above 7000 m. Left ventricular function is maintained up to 8000 m, in spite of an important increase in pulmonary artery pressure. Ventricular relaxation is altered, probably because of altered ventricular filling. The decrease in food intake contributes to the loss of body weight (mean of 5.4 kg). Nutritional habits are modified, with shorter and more frequent meals and a decreased interest for food. Lipolysis in fat tissue is blunted, suggesting, like for cardiac adrenergic receptors, a desensitization linked to a change in G proteins. Few psychological alterations were observed below 6500 m. However, changes in mood state and a high level of anxiety have been noticed and correlated to other physiological or psychometric parameters.Conclusion – Human body is able to develop adequate responsive mechanisms to oppose the severe hypoxia (mean arterial PO₂ of 30.6 mmHg at 8,848 m). Mental capacities are also slightly diminished, but only above 6500 m.     

Hallazgos en la tomografía computarizada de tórax en las fases evolutivas de la infección por SARS-CoV-2

ObjectiveTo compare the findings on chest computed tomography (CT) in patients with COVID-19 during different phases of the disease and to evaluate the reproducibility of a visual radiologic score for estimating the extent of lung involvement.MethodsWe retrospectively reviewed chest CT studies from 182 patients with RT-PCR findings positive for SARS-CoV-2. Patients were classified according to the time elapsed from the onset of symptoms, as follows: early (0-4 days), intermediate/progressive (5-9 days), or advanced (≥10 days). We analyzed the frequency of each radiologic finding, as well as the pattern, appearance, and predominant distribution of lung involvement. A visual tomographic score (range, 0-25) was used to estimate the extent of involvement in each lobe and in the total lung volume.ResultsThe predominant CT finding was the ground-glass pattern (n=110; 60.4%), the most common distribution was peripheral (n = 116; 66.7%), and the most prevalent appearance was typical (n=112; 61.5%). The halo sign was seen most frequently in the early phase (25%), whereas ground-glass opacities were more common in the intermediate/progressive and advanced phases. The median severity score was 10 (IQR: 5-13), and the scores increased as the disease progressed. The interobserver agreement (kappa) was 0.92 for the appearance, 0.84 for the distribution, 0.70 for the predominant pattern, and 0.89 for the visual score.ConclusionThe CT findings in patients with COVID-19 vary with the course of the infection. The proposed visual radiologic score is a simple, reproducible, and reliable tool for assessing lung involvement in COVID-19 pneumonia.     

Adaptations métaboliques à l'entraînement en début de saison de natation. Différences en fonction du sexe

Purpose – In this study, we compared the early metabolic adaptations to swim training between healthy men (n = 7) and women (n = 8).Methods – On the 1^st, 3^rd and 5^th testing sessions, plasma Fourier-transform infrared (FT-IR) spectra were obtained at the resting state and after each standardized testing session.Results – At the 1^st testing session, glycemia decreased more in females than in males (respectively, –1.101, –0.687 mmol.l^–1), triglycerides (TG) increased in females (0.184 mmol/l) and decreased in males (–0.094 mmol.l^–1) and males presented a higher plasma urea increase (p < 0.05). At the third testing session, glycemia increased in females (0.458 mmol.l^–1) whereas it decreased in males (–0.601 mmol.l^–1). Plasma urea increased more in males compared to females during exercise (p < 0.01). On the other hand, Apo B increased in females (0.063 g.l) and decreased in males (–0.073 g.l^–1) during exercise. At the 5^th testing session, males and females exhibited an equivalent metabolic response to exercise. However, IgA, IgG₁, IgG₃ and IgM were significantly different during exercise in males and females (p < 0.01) throughout the three sessions.Conclusions – Indeed, although metabolic adaptations to early phases of swim training were different, male and female subjects finally exhibited the same global metabolic response to endurance exercise. However immunity response to exercise in women and men was different throughout the three testing sessions.