Estudio de la capacidad de salto en inmersión

El propósito de este análisis ha sido examinar los efectos del EP de la muestra de estudio seleccionada tanto en seco como en inmersión mediante el entrenamiento del salto vertical sin contramovimiento (SJ) y con contramovimiento (CMJ), el salto DJ30/50 (salto con una caída procedente de una altura de 30 ó 50 cm, del término inglés “drop jump”), el salto RJ10 (test de saltos reactivos, consistente en realizar 10 saltos de manera continua buscando la máxima altura en cada uno de ellos, del término inglés “repeat jump 10”) y la concentración de creatinquinasa (CK). Desarrollo teórico Los programas de entrenamiento se realizaron en un periodo de 6 semanas en el estudio piloto y otro de 10 semanas para permitir la realización de todos los aspectos del estudio y permitiendo el tiempo suficiente para las adaptaciones de entrenamiento potenciales. Se sometieron a un programa de entrenamiento de dos sesiones semanales en días no consecutivos y simultáneos para ambos grupos a lo largo de un total de 12 sesiones para el estudio piloto y 20 para el posterior. Con anterioridad a cada sesión de entrenamiento, los participantes realizaban un calentamiento, consistente en un periodo de activación por medio de 5 minutos de movilidad articular, en el que aparecían los movimientos activos libres localizados en las cadenas cinéticas, tanto superiores como inferiores y amplitud de movimiento, más 5 minutos de carrera continua lenta. En conclusión, 1.- La participación en el estudio durante seis semanas de entrenamiento demuestra que ambos grupos mejoran el rendimiento, tanto en inmersión como en seco, sin que se produzcan diferencias significativas para un período de 6 semanas, tanto en el salto vertical SJ como CMJ. Teniendo el grupo EPA y EP una tendencia a seguir mejorando al cabo de seis semanas, siendo éste último período y carga de trabajo los óptimos. 2.- El EPA y EP produce a lo largo de 6 semanas mejoras no significativas en el rendimiento del salto vertical, siendo el EP una mejor opción para la obtención de mejores valores tras un período de 10 semanas. 3.- A partir de los 350 saltos por sesión se reducen los resultados obtenidos en lugar de incrementarlos. 4.- El EP obtuvo mejoras significativas en las variables analizadas (RJ10: 97/3/0; DJ30: 97/3/0; DJ50: 100/0/0). Sin embargo, los saltos en profundidad no obtienen mejores resultados en los EPA tras 10 semanas de entrenamiento (RJ10: 50/42/9; DJ30: 83/17/0; DJ50: 63/36/1), debido, probablemente, a la especificidad del salto y la inhibición del reflejo miotático así como al retardo de la velocidad del CEA. 5.- Ambos grupos de entrenamiento mostraron curiosamente una mayor concentración de CK en relación al test intermedio y final, a pesar de aumentar el volumen de entrenamiento de 300 a 500 saltos (83,3%) por ciclo de sesión. Sin embargo, el EP parece producir un daño muscular mayor que el EPA (15,0% frente a 3,2%), siendo mayor la rigidez muscular evaluada

Influence of stretching on warm up in jump and speed

El objetivo del estudio es determinar si la realización de estiramientos pasivos, incluidos como parte del calentamiento, influyen en el rendimiento de la fuerza explosiva, en este caso en varios tests de salto vertical: Squat Jump (SJ), Countermouvement Jump (CMJ) y Reactive Jump (RJ); y también en un test de velocidad de 30 metros (mts.) con salida lanzada de 5 mts. Para ello, 9 jugadores del Málaga Club de Fútbol de categoría juvenil (18,22 ± 0,441 años) realizaron 2 protocolos de calentamiento en dos semanas consecutivas en su día de recuperación. Los jugadores de fútbol utilizan los estiramientos pasivos en su calentamiento y el tipo de esfuerzo al que se someten durante su actividad tiene un alto componente de fuerza explosiva de tipo balístico, movimientos que se ejecutan con gran intensidad y corta duración, tales como golpear el balón, sprints, cambios de dirección, saltos, etc. Se han encontrado disminuciones en el rendimiento de los test de SJ y RJ, así como también en el test de velocidad, obteniéndose valores significativos (p<0,05) tanto para la potencia y el tiempo de vuelo del test RJ, como también para el test de velocidad. En cuanto al test CMJ, se han obtenido beneficios aunque las diferencias no han sido significativas. Por tanto, la realización de estiramientos pasivos influye de forma negativa en el rendimiento de la fuerza explosiva y la velocidad en una muestra de futbolistas entrenados

Effects of land vs. Aquatic plyometric training on vertical jump

El objetivo de este estudio fue comparar los efectos de dos programas de entrenamiento pliométrico (inmersión vs. seco) sobre el salto vertical. 65 hombres físicamente activos fueron asignados aleatoriamente a tres grupos: entrenamiento pliométrico acuático (EPA, n 20), entrenamiento pliométrico (EP, n=20) y grupo control (GC, n=25). Los grupos EPA y EP entrenaron 2 sesiones por semana durante 10 semanas, mientras que GC no realizó entrenamiento alguno. El volumen de entrenamiento fue aumentado desde 10 series de 10 repeticiones en la primera semana hasta 10 series de 55 repeticiones en la última. Tanto EPA como EP aumentaron su rendimiento en CMJ y SJ con respecto al pretest (P≤0,001) sin encontrar diferencias significativas entre grupos, mientras que GC no mostró cambios. Como conclusión, el EPA puede ser un método alternativo a EP ya que ambos producen similares mejoras sobre el salto vertical y el estrés mecánico producido por EPA es menoThe aim of this study was to compare the effects of two plyometric training program (aquatic vs. land) on vertical jump. 65 male physical education students took part in this study and were randomly assigned to three groups: aquatic plyometric training group (APT, n = 20), plyometric training group (PT, n = 20) and control group (CG, n = 25). The training program was performed for 10 weeks with a frequency of 2 sessions per week. Volume was increased from 10 sets of 10 repetitions to 10 sets of 55 repetitions. Both APT and PT increased the performance in CMJ and SJ with respect to pretest (P ≤ .001), whereas CG remained unaltered. No statistically significant difference was observed between APT and PT. In conclusion, APT may be an alternative method to PT, because both training protocols have produced similar gains in the vertical jump, but APT might cause lower mechanical stres

Influencia del estiramiento en el calentamiento para el salto y la velocidad

The purpose of the study is to determine the influence of passive stretchings included as part of warm up in explosive strength performance, in this case in several vertical jump tests: Squat Jump (SJ), Countermouvement Jump (CMJ) and Reactive Jump (RJ); and also in a 30 meters speed test with 5 meters start flying.Sample was composed by 9 male Málaga Football Club soccerplayers (18.22 ± 0.44 years) performed 2 warm up protocols in they free day in two consecutive weeks. The soccer players use the passive stretching in warm up and the kind of effort during the activity has a high component of explosive ballistic strength, movements executed by great intensity and short duration, for example shoot the ball, sprints, way changes, jumps, etc.Were observed decreases in SJ, RJ and speed tests performance, with statistic significant differences (p&lt;0.05) in power and flight time of RJ test, also in speed test. As for the CMJ test, benefits have been obtained though the differences have not been significant. Therefore, passive stretching included in warm up had a negative influence in explosive strength and speed in trained soccer players group.El objetivo del estudio es determinar si la realización de estiramientos pasivos, incluidos como parte del calentamiento, influyen en el rendimiento de la fuerza explosiva, en este caso en varios tests de salto vertical: Squat Jump (SJ), Countermouvement Jump (CMJ) y Reactive Jump (RJ); y también en un test de velocidad de 30 metros (mts.) con salida lanzada de 5 mts.            Para ello, 9 jugadores del Málaga Club de Fútbol de categoría juvenil (18,22 ± 0,441 años) realizaron 2 protocolos de calentamiento en dos semanas consecutivas en su día de recuperación. Los jugadores de fútbol utilizan los estiramientos pasivos en su calentamiento y el tipo de esfuerzo al que se someten durante su actividad tiene un alto componente de fuerza explosiva de tipo balístico, movimientos que se ejecutan con gran intensidad y corta duración, tales como golpear el balón, sprints, cambios de dirección, saltos, etc.             Se han encontrado disminuciones en el rendimiento de los test de SJ y RJ, así como también en el test de velocidad, obteniéndose valores significativos (p&lt;0,05) tanto para la potencia y el tiempo de vuelo del test RJ, como también para el test de velocidad. En cuanto al test CMJ, se han obtenido beneficios aunque las diferencias no han sido significativas. Por tanto, la realización de estiramientos pasivos influye de forma negativa en el rendimiento de la fuerza explosiva y la velocidad en una muestra de futbolistas entrenados

Spectral performance of the Microchannel X-ray Telescope on board the SVOM mission

The Microchannel X-ray Telescope (MXT) is an innovative compact X-ray instrument on board the SVOM astronomical mission dedicated to the study of transient phenomena such as gamma-ray bursts. During 3 weeks, we have tested the MXT flight model at the Panter X-ray test facility under the nominal temperature and vacuum conditions that MXT will undergo in-flight. We collected data at series of characteristic energies probing the entire MXT energy range, from 0.28 keV up to 9 keV, for multiple source positions with the center of the point spread function (PSF) inside and outside the detector field of view (FOV). We stacked the data of the positions with the PSF outside the FOV to obtain a uniformly illuminated matrix and reduced all data sets using a dedicated pipeline. We determined the best spectral performance of MXT using an optimized data processing, especially for the energy calibration and the charge sharing effect induced by the pixel low energy thresholding. Our results demonstrate that MXT is compliant with the instrument requirement regarding the energy resolution (<80 eV at 1.5 keV), the low and high energy threshold, and the accuracy of the energy calibration ($\pm$20 eV). We also determined the charge transfer inefficiency (~$10^{-5}$) of the detector and modeled its evolution with energy prior to the irradiation that MXT will undergo during its in-orbit lifetime. Finally, we measured the relation of the energy resolution as function of the photon energy. We determined an equivalent noise charge of 4.9 $\pm$ 0.2 e- rms for the MXT detection chain and a Fano factor of 0.131 $\pm$ 0.003 in silicon at 208 K, in agreement with previous works. This campaign confirmed the promising scientific performance that MXT will be able to deliver during the mission lifetime.Comment: 20 pages, 10 figures, accepted for publication in Experimental Astronom

Comparison of cloud products within IASI footprints for the assimilation of cloudy radiances

This article compares different methods of deriving cloud properties in the footprint of the Infrared Atmospheric Sounding Interferometer (IASI), onboard the European MetOp satellite. Cloud properties produced by ten operational schemes are assessed and an intercomparison of the products for a 12 h global acquisition is presented. Clouds cover a large part of the Earth, contaminating most of the radiance data. The estimation of cloud top height and effective amount within the sounder footprint is an important step towards the direct assimilation of cloud-affected radiances. This study first examines the capability of all the schemes to detect and characterize the clouds for all complex situations and provides some indications of confidence in the data. Then the dataset is restricted to thick overcast single layers and the comparison shows a significant agreement between all the schemes. The impact of the retrieved cloud properties on the residuals between calculated cloudy radiances and observations is estimated in the long-wave part of the spectrum

Molecular composition of clouds: a comparison between samples collected at tropical (Réunion Island, France) and mid-north (Puy de Dôme, France) latitudes

The composition of dissolved organic matter of cloud water has been investigated through non-targeted high-resolution mass spectrometry on only a few samples that were mostly collected in the Northern Hemisphere in the USA, Europe and China. There remains, therefore, a lack of measurements for clouds located in the Southern Hemisphere, under tropical conditions and influenced by forest emissions. As a matter of fact, the comparison of the composition of clouds collected in different locations is challenging since the methodology for the analysis and data treatment is not standardized. In this work, the chemical composition of three samples collected at Réunion Island (REU) during the BIO-MAÏDO field campaign, in the Indian Ocean, with influences from marine, anthropogenic and biogenic (tropical) emissions, is investigated and compared to the chemical composition of samples collected at the Puy de Dôme (PUY) observatory in France. The same methodology of analysis and data treatment was employed, producing a unique dataset for the investigation of the molecular composition of organic matter in cloud water. Besides the analysis of elemental composition, we investigated the carbon oxidation state (OSC) of dissolved organic matter, finding that overall samples collected at PUY are more oxidized than those collected at REU. Molecular formulas were also classified based on stoichiometric elemental ratios, showing the high frequency and abundance of reduced organic compounds, classified as lipids (LipidC), in this matrix, which led to a search for terpene oxidation products in cloud water samples. To better discriminate between samples collected at PUY and REU, statistical analysis (principal component analysis and agglomerative hierarchical clustering) was performed on the ensemble of molecular formulas and their intensities. Samples collected at REU have a different composition from samples collected at PUY, which is mainly linked to different primary sources, the processing of organic matter in cloud water and the influence of different primary emissions at the two locations.</p

Towards IASI-New Generation (IASI-NG): impact of improved spectral resolution and radiometric noise on the retrieval of thermodynamic, chemistry and climate variables

Besides their strong contribution to weather forecast improvement through data assimilation, thermal infrared sounders onboard polar-orbiting platforms are now playing a key role for monitoring atmospheric composition changes. The Infrared Atmospheric Sounding Interferometer (IASI) instrument developed by the French space agency (CNES) and launched by Eumetsat onboard the Metop satellite series is providing essential inputs for weather forecasting and pollution/climate monitoring owing to its smart combination of large horizontal swath, good spectral resolution and high radiometric performance. EUMETSAT is currently preparing the next polar-orbiting program (EPS-SG) with the Metop-SG satellite series that should be launched around 2020. In this framework, CNES is studying the concept of a new instrument, the IASI-New Generation (IASI-NG), characterized by an improvement of both spectral and radiometric characteristics as compared to IASI, with three objectives: (i) continuity of the IASI/Metop series; (ii) improvement of vertical resolution; (iii) improvement of the accuracy and detection threshold for atmospheric and surface components. In this paper, we show that an improvement of spectral resolution and radiometric noise fulfill these objectives by leading to (i) a better vertical coverage in the lower part of the troposphere, thanks to the increase in spectral resolution; (ii) an increase in the accuracy of the retrieval of several thermodynamic, climate and chemistry variables, thanks to the improved signal-to-noise ratio as well as less interferences between the signatures of the absorbing species in the measured radiances. The detection limit of several atmospheric species is also improved. We conclude that IASI-NG has the potential for strongly benefiting the numerical weather prediction, chemistry and climate communities now connected through the European GMES/Copernicus initiative

Collecting and utilising crowdsourced data for numerical weather prediction: propositions from the meeting held in Copenhagen, 4–December 5, 2018

In December 2018, the Danish Meteorological Institute organised an international meeting on the subject of crowdsourced data in numerical weather prediction (NWP) and weather forecasting. The meeting, spanning 2 days, gathered experts on crowdsourced data from both meteorological institutes and universities from Europe and the United States. Scientific presentations highlighted a vast array of possibilities and progress being made globally. Subjects include data from vehicles, smartphones, and private weather stations. Two groups were created to discuss open questions regarding the collection and use of crowdsourced data from different observing platforms. Common challenges were identified and potential solutions were discussed. While most of the work presented was preliminary, the results shared suggested that crowdsourced observations have the potential to enhance NWP. A common platform for sharing expertise, data, and results would help crowdsourced data realise this potential