Breath-hold diving performance factors

In this study we analyzed the relation of several predictors with Apnea Indoor. 56 divers participated in this observational research. Were measured the individual performance in Apnea Indoor, hemoglobine, blood volume, VO2max, body composition, resting metabolic rate and the heart rate and oxygen saturation during a maximal static apnea. We noted a correlation between vital capacity (r = 0.539; p≤0.05), blood volume (r = 0.466; p ≤0.05), body lean percentage (r = 0.406; p ≤0.05) the minimal heart rate (r = -0.624; p ≤0.05) and the lowest oxygen saturation 0.485; p ≤0.05) obtained during static apnea with Apnea Indoor performance

Interrelationship between different loads in resisted sprints, half-squat 1RM, and kinematic variables in trained athletes

Resisted sprint running is a common training method for improving sprint-specific strength. It is well-known that an athlete's time to complete a sled-towing sprint increases linearly with increasing sled load. However, to our knowledge, the relationship between the maximum load in sled-towing sprint and the sprint time is unknown, The main purpose of this research was to analyze the relationship between the maximum load in sled-towing sprint, half-squat maximal dynamic strength and the velocity in the acceleration phase in 20-m sprint. A second aim was to compare sprint performance when athletes ran under different conditions: un-resisted and towing sleds. Twenty-one participants (17.86±2.27 years; 1.77±0.06 m and 69.24±7.20 kg) completed a one repetition maximum test (1 RM) from a half-squat position (159.68±22.61 kg) and a series of sled-towing sprints with loads of 0, 5, 10, 15, 20, 25, 30% body mass (Bm) and the maximum resisted sprint load. No significant correlation (P<0.05) was found between half-squat 1 RM and the sprint time in different loaded conditions. Conversely, significant correlations (P<0.05) were found between maximum load in resisted sprint and sprint time (20-m sprint time, r=−0.71; 5% Bm, r=−0.73; 10% Bm, r=−0.53; 15% Bm, r=−0.55; 20% Bm, r=−0.65; 25% Bm, r=−0.44; 30% Bm, r=−0.63; MaxLoad, r= 0.93). The sprinting velocity significantly decreased by 4–22% with all load increases. Stride length (SL) also decreased (17%) significantly across all resisted conditions. In addition, there were significant differences in stride frequency (SF) with loads over 15% Bm. It could be concluded thatthe knowledge of the individual maximal load in resisted sprint and the effects on the sprinting kinematic with different loads, could be interesting to determinate the optimal load to improve the acceleration phase at sprint running.Actividad Física y Deport

Effects of Sled Towing on Peak Force, the Rate of Force Development and Sprint Performance During the Acceleration Phase

Resisted sprint training is believed to increase strength specific to sprinting. Therefore, the knowledge of force output in these tasks is essential. The aim of this study was to analyze the effect of sled towing (10%, 15% and 20% of body mass (Bm)) on sprint performance and force production during the acceleration phase. Twenty-three young experienced sprinters (17 men and 6 women; men = 17.9 ± 3.3 years, 1.79 ± 0.06 m and 69.4 ± 6.1 kg; women = 17.2 ± 1.7 years, 1.65 ± 0.04 m and 56.6 ± 2.3 kg) performed four 30 m sprints from a crouch start. Sprint times in 20 and 30 m sprint, peak force (Fpeak), a peak rate of force development (RFDpeak) and time to RFD (TRFD) in first step were recorded. Repeated-measures ANOVA showed significant increases (p ≤ 0.001) in sprint times (20 and 30 m sprint) for each resisted condition as compared to the unloaded condition. The RFDpeak increased significantly when a load increased (3129.4 ± 894.6 N·s-1, p ≤ 0.05 and 3892.4 ± 1377.9 N·s-1, p ≤ 0.01). Otherwise, no significant increases were found in Fpeak and TRFD. The RFD determines the force that can be generated in the early phase of muscle contraction, and it has been considered a factor that influences performance of force-velocity tasks. The use of a load up to 20% Bm might provide a training stimulus in young sprinters to improve the RFDpeak during the sprint start, and thus, early acceleration.Actividad Física y Deport

Isokinetic leg strength and power in elite handball players

Isokinetic strength evaluation of the knee flexion and extension in concentric mode of contraction is an important part of the comprehensive evaluation of athletes. The aims of this study were to evaluate the isokinetic knee peak torque in both the extension and flexion movement in the dominant and non-dominant leg, and the relationship with jumping performance. Twelve elite male handball players from the top Spanish handball division voluntary participated in the study (age 27.68 ± 4.12 years; body mass 92.89 ± 12.34 kg; body height 1.90 ± 0.05 m). The knee extensor and flexor muscle peak torque of each leg were concentrically measured at 60º/s and 180º/s with an isokinetic dynamometer. The Squat Jump and Countermovement Jump were performed on a force platform to determine power and vertical jump height. Non-significant differences were observed between legs in the isokinetic knee extension (dominant= 2.91 ± 0.53 Nm/kg vs non-dominant = 2.70 ± 0.47 Nm/kg at 60º/s; dominant = 1.90 ± 0.31 Nm/kg vs non-dominant = 1.83 ± 0.29 Nm/kg at 180º/s) and flexion peak torques (dominant = 1.76 ± 0.29 Nm/kg vs non-dominant = 1.72 ± 0.39 Nm/kg at 60º/s; dominant = 1.30 ± 0.23 Nm/kg vs non-dominant = 1.27 ± 0.35 Nm/kg at 180º/s). Low and non-significant correlation coefficients were found between the isokinetic peak torques and vertical jumping performance (SJ = 31.21 ± 4.32 cm; CMJ = 35.89 ± 4.20 cm). Similar isokinetic strength was observed between the legs; therefore, no relationship was found between the isokinetic knee flexion and extension peak torques as well as vertical jumping performance in elite handball players.Actividad Física y Deport

Commentaries on viewpoint : physiology and fast marathons

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Reverse Periodization for Improving Sports Performance:A Systematic Review

BACKGROUND: Reverse periodization is commonly touted as a salient planning strategy to improve sport performance in athletes, but benefits have not been clearly described. OBJECTIVES: We sought to identify the main characteristics of reverse periodization, and the influence of training volume and periodization models on enhancing physiological measures and sports performance. DESIGN: Systematic review. METHODS: The electronic databases Scopus, PubMed and Web of Science were searched using a comprehensive list of relevant terms. RESULTS: A total of 925 studies were identified, and after removal of duplicates and studies based on title and abstract screening, 17 studies remained, and 11 finally included in the systematic review. There was a total of 200 athletes in the included studies. Reverse periodization does not provide superior performance improvements in swimming, running, muscular endurance, maximum strength, or maximal oxygen uptake, compared to traditional or block periodization. The quality of evidence levels for the reverse periodization studies was 1b (individual randomized controlled trial) for two investigations, 2b (individual cohort study) for the remaining studies and a mean of 4.9 points in the PEDro scale (range 0–7). CONCLUSIONS: It appears that reverse periodization is no more effective than other forms of periodization in improving sports performance. More comparative studies on this alternative version of periodization are required to verify its effectiveness and utility across a range of endurance sports

Older or Wiser? Age and Experience Trends in 20 Years of Olympic and World Swimming Championships Open Water 10-km Races

The aims of the present research were to estimate the age of peak performance (APP) and to examine the role of previous experience at the world-level open water race performances. Finishing positions and age of swimmers (639 females and 738 males) in the 10-km events of World Championship (WCH) and Olympic Games (OG) from 2000 to 2019 were obtained from the official results websites. Years of previous experience were computed using the number of previous participations in WCH or OG. APP was estimated using quadratic models of the 10th percentile top race positions and resulted in 28.94 years old for males (R2 = 0.551) and 27.40 years old for females (R2 = 0.613). Regression analysis revealed an improvement of 1.36 or 8.19 finishing positions for each additional year of age or experience, respectively (R2 = 0.157). However, significant differences (p < 0.001) between age and experience showed that the swimmer’s age became less relevant for performance as years of experience increased. These results, in terms of age, are in line with other mass-start disciplines of similar duration (≈2 h) and, in terms of experience, confirm the importance of previous participation in improving tactical decision making during open water races

Adéquation à la législation des ordonnances de sortie de l'hôpital Henri Mondor

L'objectif de cette étude est d'évaluer la qualité et la conformité à la législation des ordonnances de sortie d'hospitalisation de l'hôpital Henri Mondor à Créteil. Elle a été réalisée en étroite collaboration par les services de Santé Publique et de Pharmacie et entre dans le cadre de l'évaluation de la qualité des soins délivrés au patient. Les ordonnances ont été analysées et cotées à l'aide d'une grille d'évaluation comportant les mentions légales devant être inscrites sur une ordonnance. Au total, 308 ordonnances provenant de 23 services ont été analysées, représentant la prescription de 959 médicaments. La proportion d'ordonnances non conformes à la législation est significativement importante. Ainsi 27% des prescripteurs oublient de préciser leur nom et 57% leur qualité, 9% oublient de noter le nom du patient. En ce qui concerne le médicament, le nom n'est pas identifiable dans 1,8% des ordonnances, la forme galénique n'est pas précisée dans 29,2% des cas, le dosage dans 51,7% des cas, la posologie dans 18,2% des cas, le mode d'emploi dans 36,5% des cas, la quantité requise dans 27,7% des cas, la durée du traitement dans 7,3% des cas et le renouvellement est non ou mal formulé dans 35% des ordonnances.The objective of this study is to evaluate quality and conformity with the legislation of the ordinances of exit of hospitalization of the hospital Henri Mondor in Creteil. The ordinances were analyzed and dimensioned using a grid of evaluation comprising the legal mentions having to be registered on an ordinance. 308 ordinances coming from 23 services were analyzed, representing the regulation of 959 drugs. The proportion of ordinances nonin conformity is significant. Thus 27% of the prescribers forget to specify their name and 57% their quality, 9% forget to note the name of the patient. With regard to the drug, the name is not identifiable in 1,8% of the cases, the galenic form is not specified in 29,2% of the cases, proportioning in 51,7% of the cases, posology in 18,2% of the cases, the instructions in 36,5% of the cases, the necessary quantity in 27,7% of the cases, the duration of the treatment in 7,3% of the cases and the renewal is not or badly formulated in 35% of the ordinances.PARIS12-CRETEIL BU Médecine (940282101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Analyse des effets indésirables des inhibiteurs sélectifs de la cyclooxygénase-2 dans la banque nationale de pharmacovigilance

La découverte récente d'isoenzymes de la cyclooxygénase (COX) et des rôles respectifs de COX-1 et COX-2 ont conduit l'industrie pharmaceutique à synthétiser de nouveaux anti-inflammatoires non stéroïdiens, inhibiteurs sélectifs de la cyclo-oxygénase-2. Lors de la commercialisation du célécoxib et du rofécoxib, les essais cliniques les ont tout d'abord présentés comme induisant moins d'effets indésirables digestifs que les AINS classiques. Pourtant, leur utilisation à grande échelle a suscité de nombreuses controverses et interrogations. Cette thèse tentera de faire un point sur l'incidence réelle des effets indésirables engendrés par cette nouvelle famille thérapeutique appelée " coxib " à partir d'une analyse effectuée sur les données de la banque nationale de pharmacovigilanceTOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocSudocFranceF

Vision-Based System for Automated Estimation of the Frontal Area of Swimmers: Towards the Determination of the Instant Active Drag: A Pilot Study

Swimmers take great advantage by reducing the drag forces either in passive or active conditions. The purpose of this work is to determine the frontal area of swimmers by means of an automated vision system. The proposed algorithm is automated and also allows to determine lateral pose of the swimmer for training purposes. In this way, a step towards the determination of the instantaneous active drag is reached that could be obtained by correlating the effective frontal area of the swimmer to the velocity. This article shows a novel algorithm for estimating the frontal and lateral area in comparison with other models. The computing time allows to obtain a reasonable online representation of the results. The development of an automated method to obtain the frontal surface area during swimming increases the knowledge of the temporal fluctuation of the frontal surface area in swimming. It would allow the best monitoring of a swimmer in their swimming training sessions. Further works will present the complete device, which allows to track the swimmer while acquiring the images and a more realistic model of conventional active drag ones