Manuel Sillero Quintana

PERCEPTUAL VISUAL SKILLS IN YOUNG HIGHLY SKILLED BASKETBALL PLAYERS

A simple method was designed to evaluate visual abilities such as distance visual acuity, binocular horizontal visual field, simple and choice visual reaction times, and stereoscopic vision in skilled 11- to 13-yr.-old basketball players participating in a 15-day summer training camp. On a test battery, visual abilities were monitored in 473 players of the Spanish Basketball Federation over a 5-yr. period. The players showed outstanding scores on distance visual acuity and stereoscopic vision, and good visual reaction times and horizontal visual fields. When scores were compared by sex and age, significant differences on certain visual measures were observed. Many players showed crossed eye-hand dominance. Visual screening programs may help promote visual health among junior basketball players and could be used for performance training.

Relación del nivel de actividad física, presión arterial y adiposidad corporal en adolescentes madrileños

Fundamento: La creciente preocupacion por la salud ha suscitado un enorme interes en el estudio de los factores que inciden sobre ella. El objetivo de este trabajo es analizar la influencia del nivel de actividad fisica (NAF) en la salud de los adolescentes y determinar su relacion con la presion arterial (PA) y la composicion corporal. Metodos: La investigacion se realizo entre noviembre de 2002 y febrero de 2003 utilizando el Cuestionario Modificable de Actividad Fisica para Adolescentes que mide el nivel de actividad fisica. Tambien se midieron la composicion corporal y la presion arterial, en una muestra compuesta por 554 adolescentes de 35 centros educativos de Madrid, con edades comprendidas entre 12 y 18 anos. Resultados: Resultaron inactivos el 13,2% de los varones y el 36,4% de las mujeres. Los promedios para las PA sistolica/diastolica fueron de 125,6/71,3 mmHg en los varones y 118/69,4 mmHg en las mujeres, pero solo se detecto influencia del nivel de actividad fisica en la PA diastolica para los varones. Presentaron tendencia al sobrepeso el 48,27% de las mujeres frente al 13,53% de los hombres. En el caso de las mujeres se encontro relacion entre adiposidad corporal y nivel de actividad fisica. Conclusiones: El nivel de actividad fisica se presenta como un factor asociado a la salud de los adolescentes, si bien se manifiesta de forma distinta en cada sexo. En los hombres afecta significativamente a la PA diastolica, mientras que en las mujeres su influencia se detecta en el grado de adiposidad corporal.

Modeling the basin of attraction as a two-dimensional manifold from experimental data: applications to balance in humans.

We present a method of modeling the basin of attraction as a three-dimensional function describing a two-dimensional manifold on which the dynamics of the system evolves from experimental time series data. Our method is based on the density of the data set and uses numerical optimization and data modeling tools. We also show how to obtain analytic curves that describe both the contours and the boundary of the basin. Our method is applied to the problem of regaining balance after perturbation from quiet vertical stance using data of an elite athlete. Our method goes beyond the statistical description of the experimental data, providing a function that describes the shape of the basin of attraction. To test its robustness, our method has also been applied to two different data sets of a second subject and no significant differences were found between the contours of the calculated basin of attraction for the different data sets. The proposed method has many uses in a wide variety of areas, not just human balance for which there are many applications in medicine, rehabilitation, and sport.

Detecting changes in the basin of attraction of a dynamical system: Application to the postural restoring system

A method that provides a three-dimensional representation of the basin of attraction of a dynamical system from experimental data was applied to the problem of dynamic balance restoration. The method is based on the density of the data on the phase space of the system under study and makes use of modeling and numerical curve fitting tools. For the dynamical system of balance restoration, the shape and the size of the basin of attraction depend on the dynamics of the postural restoring mechanisms and contain important information regarding the biomechanical, as well as the neuromuscular condition of the individual. The aim of this work was to examine the ability of the method to detect, through the observed changes in the shape and/or the size of the calculated basins of attraction, (a) the inherent differences between different systems (in the current application, postural restoring systems of different individuals) and (b) induced changes in the same system (the postural restoring system of an individual). The results of the study confirm the validity of the method and furthermore justify its robustness.

Sobre l’expressió “resposta de reacció” i el concepte “temps de resposta”

En l’ambit academic es fonamental una definicio unificada de conceptes i termes que beneficii la comunicacio entre cientifics i les recerques bibliografiques. Tanmateix, en la bibliografia espanyola no hi ha una expressio unificada per anomenar la suma del temps de reaccio i el temps de moviment. La revisio de la bibliografia en castella mostra que l’expressio comunament utilitzada es “resposta de reaccio”, que va ser inicialment utilitzada en el llibre Tiempo de reaccion y deporte de Josep Roca (1983) i que, posteriorment, ha estat traduida a l’angles com reaction response per part d’autors espanyols. No obstant, en la literatura internacional s’utilitza temps de reponse o temps total de reponse en frances i response time o total response time en angles. Realitzant una recerca en bases de dades internacionals, es comprova que l’expressio “resposta de reaccio” no es utilitzada fora de l’ambit castellanoparlant. A mes a mes, en aquest article es discuteix sobre si realment el seu significat s’adapta al concepte que representa. Per ultim, se suggereix l’us de les expressions “temps de resposta” o “temps total de resposta”, que s’adequen millor al seu significat literal i a la bibliografia internacional.