Evaluación comparativa de la distribución corporal de tejido adiposo entre jugadores de fútbol profesionales, semiprofesionales y amateurs

La preparación física en el ámbito del fútbol ha adquirido una gran importancia en los últimos años. El objetivo de este estudio es evaluar la distribución corporal de tejido graso en 150 futbolistas, divididos por igual en las categorías profesionales (2ª A División), semiprofesionales (2ªB División) y no profesionales (3ª División) de la liga de fútbol española. Se valora peso, talla y 9 pliegues cutáneos grasos, además del sumatorio de 6 y 9 pliegues, relación grasa troncal / extremidades y porcentaje de grasa (Carter). Se obtuvo el correspondiente consentimiento informado del deportista y se utilizó el análisis de la varianza (ANOVA) para la comparación entre los grupos (p < 0.05). Los resultados muestran que a medida que disminuye la categoría profesional los jugadores tienen un mayor acumulo de tejido adiposo corporal, que se manifiesta en un mayor porcentaje de grasa corporal, indicando una tendencia a aumentar su depósito en las extremidades respecto al tronco. La preparación deportiva y la exigencia física son directamente proporcionales a la categoría profesional, con tendencia a un aumento del depósito graso en las extremidades en las divisiones no profesionales.Peer Reviewe

Morfotipo del futbolista profesional de la Comunidad Autónoma de Madrid. Composición corporal

La composición corporal es dentro del estudio cineantropométrico de la población de atletas la que se utiliza con mayor frecuencia, ya que permite de manera inmediata tener una visión global del morfotipo del futbolista sobre el cual se puede actuar modificándolo fácilmente por medio de una adecuada preparación física. Se estudiaron 56 jugadores de fútbol profesional que desarrollan su actividad física en la Comunidad Autónoma de Madrid, de manera voluntaria, obteniéndose el consentimiento informado previo de cada uno de ellos de acuerdo a la legislación vigente. La composición corporal se realizó mediante la segmentación del cuerpo humano en cuatro componentes. El análisis estadístico se realizó utilizando el programa de software compatible con PC SPSS 11.5. La edad media de los jugadores estudiados es de 26.087 (edad decimal) ± 3.48 años, la talla media es de 177.87 ± 6.78 cm., el peso medio es de 77.24 ± 5.60 Kg., el porcentaje de grasa medio es de un 10.42 ± 0.70%, el porcentaje muscular es de un 50,04 ± 0.79%, el porcentaje óseo es de un 15.44 ± 0.73% y el peso residual de un 24.10%

Cambios de la proporcionalidad corporal durante el crecimiento en edades adolescentes

La adolescencia es una etapa crítica de la ontogenia caracterizada por importantes cambios en la velocidad de crecimiento de los tejidos que afectan al tamaño, forma y composición corporal, lo que origina profundas diferencias alométricas entre los individuos según el sexo y estadío madurativo. El presente estudio aborda la valoración del grado de madurez, como índice de salud del adolescente, en función de los índices Z del modelo estándar de proporcionalidad corporal conocido como «Phantom», que representa al promedio poblacional adulto. Aplicando el método antropométrico, se analiza una muestra de 360 adolescentes, entre 10 y 15 años y se encuentra que hacia edades más avanzadas los índices Z de las distintas variables antropométricas se aproximan mejor a los valores del Phantom, hallándose diferencias en la progresión de dichos índices según el sexo, por lo que se debate la adecuación de éste modelo a la interpretación de la realidad cambiante del cuerpo humano

Estudio de dos propuestas sobre el modelo «phantom» de proporcionalidad de Ross y Wilson

El modelo «Phantom» de proporcionalidad de Ross y Wilson (1974) plantea dificultades cuando se trata de evaluar la proporcionalidad de individuos cuyos patrones normales se alejan de los promedios estándar poblacionales; muy especialmente en deportistas de élite o individuos en fase de crecimiento. Por este motivo, en los últimos años han aparecido propuestas de variación sobre el modelo «Phantom», como el Método Combinado propuesto por Lentini (2004) y el Método Escalable propuesto por nuestro grupo de investigación en 2005. En el presente artículo se hace un estudio comparativo de ambos métodos. The proportionality «Phantom» model of Ross and Wilson (1974) creates difficulties for evaluate the proportionality of individuals whose normal patrons are outside the population averages standard; very especially for elite athlete or individuals in growth phase. For this reason, in the last years, proposals of variation on the «Phantom» model have appeared, such as the Combined Method proposed by Lentini (2004) and the Scalable Method proposed by our rechearch team in 2005. The present article is a comparative study of both methods

Estimación del grado de desarrollo de la composición corporal en deportistas púberes y prepúberes

Un valioso elemento en la vigilancia de la salud pediátrica es la gráfica de recimiento, que relaciona en curvas de percentil la edad con el peso y la talla. Bastante útiles en edades preescolares, son poco representativas de los cambios producidos en etapas adolescentes en las que se añade al crecimiento normal, los cambios fisiológicos propios del desarrollo puberal y factores ambientales tales como la practica de actividades deportivas, que pueden inducir un desarrollo diferente de cada componente corporal. Aplicando el método antropométrico se calcula la composición corporal de 300 escolares entre 10 y 15 años, estudiando el fraccionamiento del peso corporal en 4 componentes. Los objetivos del presente estudio son: conocer cómo cambian los distintos componentes corporales durante las etapas preadolescente y adolescente de los individuos que realizan deporte extraescolar y obtener gráficas de crecimiento para cada componente similares a las existentes para la correlación edad/peso, edad/talla, peso/talla aceptadas por la OMS y de idéntico manejo, que muestren las variables en percentiles por edad, no en términos de proporción del peso total, sino en valor absoluto para cada componente, de modo que permitan monitorizar el desarrollo de cada individuo, resultando así de utilidad en la práctica clínica diaria.Los resultados de la artroplastia de codo han mejorado sustancialmente coincidiendo con el mejor conocimiento de la biomecánica del codo. El diseño y los resultados clínicos de las prótesis de codo se basan en un conocimiento preciso de la cinemática, los estabilizadores y las fuerzas que atraviesan esta articulación.A valuable element in the vigilance of the pediatric health is the graph of growth which relates in curves of percentile the age with the weight and the height. Very useful in preschool ages, they are not very representative in the changes of the adolescent stages in which, to the normal growth, it adds the physiologic changes characteristic of the development puberal and environmental factors just as practice of sport activities that can induce a different development in each corporal component. Applying the anthropometric method, the body composition of 300 scholars, between 10 and 15 years old, is calculated, studying the division of the corporal mass according to four compartment model. The objectives of the present study are: to know the change of the different corporal components during the preadolescent and adolescent stages of the people whom practice extra-school sport and to obtain graphics of growth for each component similar to the existent ones for the correlation age/weight, age/height, weight/height accepted by the WHO and of identical handling that show the variables in percentiles for age, not in terms of proportion of the total weight, but in absolute value for each component, so they allow to monitor the development of each person, being that utility in the everyday clinical practice

Left wind forward in football (soccer). Khinanthropometry and footprint analysis

Kinanthropometry is the study of size, shape, proportionality, body composition, biological maturation and body function with the objective of understanding the process of growth, exercise, sport performance and nutrition. It has been accepted measurements in the right side of the subject as equivalent of the overall sportsman. Right and left side variations therefore have not been sufficiently studied, particularly in left handed football players. Materials and Methods: Analysis of 5 professional footballers from the C.D. Leganés, S.A.D. was carried, being left dominant and by their team position considered as left wing forwards. The method selected to study kinanthropometric variables was established by Heath-Carter and followed by the ISAK-GREC (International Society for the Advancement of Kinanthropometry and Grupo Español de Cineantropometría-Spanish Group of Kinanthropometry-). Footprint obtained by the simplified Hernandez-Corvo methodology, being classified as: flat, flat-normal, normal, normal-high arch, high arch, strong high arch and extreme high arch, prior and subsequent to a football match. Informed consent attained as established by local legislation. Statistics analysed by t-Student with a significance of 95% (p<0.05) and the results processed by the PC statistical software SPSS 11.5. Results: Football players have a mean height of 174.02 cm. and a mean weight of 75.32 Kg. Right foot mean length is 24.84 cm. and left foot mean length is 24.96 cm., while right foot mean width is 9.73 cm. and left foot mean width is 9.60 cm.; the footprint varies from normal prior to match to normal- high arch after the game, whereas left foot remains normal-high arch all along. Total number of lesions accounted for 9 sprains in the right ankle and 12 sprains in left ankle, 1 anterior cruciate ligament rupture and 1 menisectomy in the right knee with 1 interior lateral ligament rupture and 1 menisectomy in the left knee. Discussion: Data in variation of right and left side related to football is missing in international bibliography, which may be important due to the fact of the general belief in football environment that left dominant footballers are of better technique and therefore will have more chance of success in a world ruled by financial interests. Notice to analysis remarks the fact whereas the mean left foot is longer than the mean right foot, the mean right foot is wider than the mean left foot. Statistical significant differences arise between left and right footprint prior and subsequent to a football match, associated to statistical significant changes in various anthropometric measurements: ileospinal, throcanteric and tibial heights; total superior extremity, arm, forearm, hand, thigh, leg and foot lengths; subescapular, axillary, ileocrestal, supraspinal, thigh, leg and abdominal skinfolds; epicondyle of humerus diameter and ankle perimeter. Conclusion: 1) Footprint modifies with football practice. 2) Footprint differs in a football player in left and right feet prior and subsequent to a football match, associated with statistical discrepancies between various right and left kinanthropometric variables. 3) Broader population must be studied to better value the repercussion of football practice in footprint. 4) Research must be completed in order to analyse modification in right handed football players. 5) Research must be completed in order to analyse modification of footprint because of sport practice. 6) Research must be completed to observe differences with similar population detailing in certain sportive gestures (running, jumping, swimming, etc.)

Local Carrier PWM for Modular Multilevel Converters with Distributed PV Cells and Circulating Current Reduction

Producción CientíficaA new topology has been recently proposed for grid-connected photovoltaic (PV) systems, using modular multilevel converters (MMCs) and distributing PV panels throughout the MMC cells. This topology has two main advantages: it reduces the power losses related to moving the energy into the MMC capacitors from an external source, and it removes the losses and costs related to the DC to DC converters used to track the maximum power point on string converters or central converters, because that task is delegated to MMC cells. However, traditional pulse width modulation (PWM) techniques have many problems when dealing with this application: the distortion at the output increases to unacceptable values when MMC cells target different voltages. This paper proposes a new modulation technique for MMCs with different cell voltages, taking into account the measured cell voltages to generate switching sequences with more accurate timing. It also adapts the modulator sampling period to improve the transitions from level to level, an important issue to reduce the internal circulating currents. The proposed modulation has been validated using simulations that show a consistent behavior in the output distortion throughout a wide operation range, and it also reduces the circulating currents and cuts the conduction losses by half. The behavior of this new topology and this new modulation has been compared to the mainstream topology with external PV panels and also to a fixed carrier modulation

MMC-based topology for grid connection of wind generators with phase and arm power balancing

Producción CientíficaA new topology of a wind farm wherein the wind generators are integrated into the structure of a modular multilevel converter (MMC) is presented. It allows connecting a group of small/medium size wind turbines to the grid, replacing all the grid side converters of the wind generators by the MMC. The different power generated by each wind generator causes power imbalances that can lead to circulating currents; this paper addresses this problem by analyzing it in a simple way. The analysis shows that power differences between phases are naturally balanced by the DC component of circulating current, without the need to use a specific regulator. However, the power differences between the arms result in a high 50 Hz circulating current. This paper presents the design of a new regulator that corrects these power imbalances by generating a phase difference between the upper and lower arm voltages resulting in an optimal 50 Hz circulating current. The operation of the MMC-based wind farm topology has been tested when all the turbines generate the same power and when they generate significantly different powers. Numerical and real-time simulation results show that the proposed regulator keeps the powers of the MMC phases and arms balanced

Search for Tidal Dwarf Galaxies Candidates in a Sample of Ultraluminous Infrared Galaxies

(ABRIDGED) Star-forming small galaxies made out of collisional debris have been found in a variety of merging systems. So far only a few of them are known in ULIRGs although they show clear signs of interactions. Whether external star formation may take place in such objects is an open question. The aim of this paper is to identify and characterise the physical and kinematic properties of the external star forming regions in a sample of ULIRGs, including TDG candidates, using optical IFS and high angular resolution HST imaging. We have found that the presence of external star-forming regions is common with 12 objects being identified in 5 ULIRGs. These regions show a large range of dynamical mass up to 1x10^{10} M_sun, with average sizes of ~750 pc. In addition, the line ratios, metallicities and H\alpha equivalent widths are typical of young bursts of star formation (age ~ 5-8 Myr), and similar to those of other TDG candidates. Their extinction corrected H\alpha luminosities lead to masses for the young stellar component of ~2x10^6 - 7x10^8 M_sun. The likelihood of survival of these regions as TDGs is discussed based on their structural and kinematic properties. Most of these systems follow the relation between effective radius and velocity dispersion found for globular clusters and Ellipticals, which suggests they are stable against internal motions. The stability against forces from the parent galaxy have been studied and a comparison of the data with the predictions of dynamical evolutionary models is also performed. Five regions out of twelve show High-Medium or High likelihood of survival. Our best candidate, which satisfy all the utilized criteria, is located in the advanced merger IRAS15250+3609 and presents a velocity field decoupled from the relatively distant parent galaxy.Comment: 14 pages, 7 figures; A&A accepte

Factores estructurales, bioquímicos y moleculares de la simbiosis Bradyrhizobium sp. (Lupinus)-Lupinus

The present revision summarises some of the original works carried out in our Department to study different aspects of the peculiar symbiosis Bradyrhyzobium sp. Lupinus, by integrating structure and function. The first part of the revision is focused to a structural study on the infection mechanisms, since differ of other legumes. This study was realized by applying immunofluorescent techniques with the green fluorescent protein, immunocytochemistry and different microscopies. It could be observed that the infection by the Bradyrhizobium follows the intercellular way. The infection study includes the presence of enzymatic components, as MAPKs (Mitogen-Activated Protein Kinase) and aldehyde oxidase in the first steps of the symbiosis. Both enzymes are very much related with auxins and cell multiplication. The second part takes up the physiological, biochemical and genetic mechanisms that regulates nitrogen fixation, speccially those related to oxygen diffusion, since nitrogenase activity is very sensible to oxygen and needs a microaerobic atmosphere for its function. Between these mechanisms, the leghemoglobine and the oxygendiffusion resistance barrier have been considered the more important in oxygen regulation. Finally it is included the results of a genetic study carried out to know the genes implicated in nodule oxygen diffusion as: lenod 2, leghemoglobin and nifH.La presente revisión es un resumen de algunos trabajos originales realizados en nuestro Departamento para el estudio de diferentes aspectos de esta peculiar simbiosis, siempre integrando estructura y función. La primera parte está dedicada a un estudio estructural llevado a cabo con el fin de conocer los mecanismos de infección, que difieren de la mayoría de las leguminosas estudiadas. Para este fin se aplicaron técnicas de immunofluorescencia con la green fluorescent protein (GPT), técnicas de inmunocitoquímica y de hibridación in situ. Mediante estos estudios se ha observado que la infección se realiza por vía intercelular. Junto al estudio estructural se describen algunos componentes enzimáticos del nódulo, MAPKinasas (Mitogen-activated protein kinase) y aldehído oxidasa, presentes en estadios tempranos del reconocimiento bacteria-planta. Ambos enzimas están relacionados con la mitosis y la multiplicación de las células radicales. La segunda parte se refiere a los mecanismos fisiológicos, bioquímicos y moleculares que regulan la simbiosis, especialmente los relacionados con la regulación de oxígeno en el nódulo, de gran importancia para la fijación de N2, ya que la nitrogenasa necesita una atmósfera microaeróbica para fijar nitrógeno. Se describen algunos mecanismos de regulación, como la leghemoglobina y la barrera de resistencia a la difusión de O2. Por último también se incluye el estudio genético que realizamos para conocer los genes que regulan la difusión de O2 en el nódulo: lenod 2, leghemoglobin y nifH