Análisis cualitativo de la relación entrenador-deportista en etapas de formación en baloncesto = Qualitative analysis of the coach-athlete relationship in youth basketball

La relación entrenador-deportista estudia, dentro del ámbito de la psicología social en el deporte, la interacción de los comportamientos, sentimientos y emociones de ambos miembros de la pareja. Se entiende como un proceso en el que antecedentes como la edad, el género o las características esperadas en el otro condicionan el desarrollo de diferentes componentes, los cuales determinan la calidad de la relación, obteniéndose diferentes resultados tanto a nivel deportivo como personal. En la presente tesis se han estudiado 12 relaciones positivas entrenador-deportista en categorías de formación en baloncesto con el objetivo de conocer los condicionantes, componentes, estrategias y resultados de relaciones efectivas. Para ello, se ha realizado un estudio cualitativo, cuya muestra (N=24) se ha seleccionado de manera deliberada discriminando variables como el nivel deportivo del equipo, las características del entrenador, la duración y la calidad de la relación. Las 12 díadas participaban en el máximo nivel de su categoría, tenían una duración mínima de dos temporadas y fueron calificadas como positivas por los entrenadores principales. La investigación se ha llevado a cabo desde la perspectiva holística del fenómeno, teniendo en cuenta tanto el punto de vista del entrenador como el del jugador. Para la recogida de datos se utilizó la entrevista semiestructurada y en profundidad. Los resultados señalan la necesidad de desarrollar estrategias que promuevan y mantengan relaciones de calidad en baloncesto, ya que éstas tienen un alto impacto en el progreso deportivo y personal de los jugadores jóvenes en baloncesto. Entre los condicionantes de la relación entrenador-deportista se ha percibido que las expectativas formadas en los primeros contactos pueden determinar la calidad de la relación. Por otro lado, los componentes dan lugar a resultados como el crecimiento a nivel personal por parte de los jugadores o un mayor rendimiento deportivo, producido en gran medida por la satisfacción y el bienestar psicológico tanto del entrenador como del jugador. Por último, los resultados indican la importancia de adecuar el comportamiento del entrenador a las características propias de los jugadores en cada categoría de formación. ABSTRACT The coach-athlete relationship studies, within the field of social psychology in sport, the interaction of behavior, feelings and emotions in both partners. It is understood as a process in which antecedents such as age, gender or expectations develop different components. The quality of the relationship is determined by these three elements, leading to different results in sport performance as in personal variables. This thesis examined 12 positive coach-athlete rapports in youth basketball teams in order to better understand the determinants, components, strategies and outcomes of effective relationships. A qualitative study has been carried out. The sample (N = 24) is selected deliberately discriminating variables such as the team’s sportive level, coach characteristics, duration and quality of the relationship. Twelve dyads participated at the highest level in its category, had a minimum of two seasons and were rated as positive by head coaches. The research was conducted from a holistic perspective of the phenomenon, taking into account the point of view of both the coach and the player. Indepth semi-structured interview was used for data collection. The results report the need to develop strategies to promote and maintain high quality relationships in basketball, because they have an important impact in sport and personal development of young basketball players. Expectations raised through different impression cues in the first contacts can determine the quality of the relationship. On the other hand, the components lead to results such as players’ personal growth or sport performance, largely produced by the satisfaction and psychological well being of both the coach and the player. Finally, the results indicate the importance of adapting the coach’s behavior to the characteristics of the different stages of young athletes’ development.

An engineering modification of the blade element momentum combination applicable in vertical descent flight :fundamentals and validation

An engineering modification of blade element/momentum theory is applied to describe the vertical autorotation of helicopter rotors. A full non‐linear aerodynamic model is considered for the airfoils, taking into account the dependence of lift and drag coefficients on both the angle of attack and the Reynolds number. The proposed model, which has been validated in previous work, has allowed the identification of different autorotation modes, which depend on the descent velocity and the twist of the rotor blades. These modes present different radial distributions of driven and driving blade regions, as well as different radial upwash/downwash patterns. The number of blade sections with zero tangential force, the existence of a downwash region in the rotor disk, the stability of the autorotation state, and the overall rotor autorotation efficiency, are all analyzed in terms of the flight velocity and the characteristics of the rotor. It is shown that, in vertical autorotation, larger blade twist leads to smaller values of descent velocity for a given thrust generated by the rotor in the autorotational state.

An engineering modification of the blade element momentum equation for vertical descent : an autoration case study

An engineering modification of blade element/momentum theory is applied to describe the vertical autorotation of helicopter rotors. A full non-linear aerodynamic model is considered for the airfoils, taking into account the dependence of lift and drag coefficients on both the angle of attack and the Reynolds number. The proposed model, which has been validated in previous work, has allowed the identification of different autorotation modes, which depend on the descent velocity and the twist of the rotor blades. These modes present different radial distributions of driven and driving blade regions, as well as different radial upwash/downwash patterns. The number of blade sections with zero tangential force, the existence of a downwash region in the rotor disk, the stability of the autorotation state, and the overall rotor autorotation efficiency, are all analyzed in terms of the flight velocity and the characteristics of the rotor. It is shown that, in vertical autorotation, larger blade twist leads to smaller values of descent velocity for a given thrust generated by the rotor in the autorotational state.

Study of the influence of actin-binding proteins using linear analyses of cell deformability

The actin cytoskeleton plays a key role in the deformability of the cell and in mechanosensing. Here we analyze the contributions of three major actin cross-linking proteins, myosin II, a-actinin and filamin, to cell deformability, by using micropipette aspiration of Dictyostelium cells. We examine the applicability of three simple mechanical models: for small deformation, linear viscoelasticity and drop of liquid with a tense cortex; and for large deformation, a Newtonian viscous fluid. For these models, we have derived linearized equations and we provide a novel, straightforward methodology to analyze the experiments. This methodology allowed us to differentiate the effects of the cross-linking proteins in the different regimes of deformation. Our results confirm some previous observations and suggest important relations between the molecular characteristics of the actin-binding proteins and the cell behavior: the effect of myosin is explained in terms of the relation between the lifetime of the bond to actin and the resistive force; the presence of a-actinin obstructs the deformation of the cytoskeleton, presumably mainly due to the higher molecular stiffness and to the lower dissociation rate constants; and filamin contributes critically to the global connectivity of the network, possibly by rapidly turning over crosslinks during the remodeling of the cytoskeletal network, thanks to the higher rate constants, flexibility and larger size. The results suggest a sophisticated relationship between the expression levels of actinbinding proteins, deformability and mechanosensing.

Application of the homogenization techniques to the determination of the effective flexure constants of plate structural systems

A Mindlin plate with periodically distributed ribs patterns is analyzed by using homogenization techniques based on asymptotic expansion methods. The stiffness matrix of the homogenized plate is found to be dependent on the geometrical characteristics of the periodical cell, i.e. its skewness, plan shape, thickness variation etc. and on the plate material elastic constants. The computation of this plate stiffness matrix is carried out by averaging over the cell domain some solutions of different periodical boundary value problems. These boundary value problems are defined in variational form by linear first order differential operators on the cell domain and the boundary conditions of the variational equation correspond to a periodic structural problem. The elements of the stiffness matrix of homogenized plate are obtained by linear combinations of the averaged solution functions of the above mentioned boundary value problems. Finally, an illustrative example of application of this homogenization technique to hollowed plates and plate structures with ribs patterns regularly arranged over its area is shown. The possibility of using in the profesional practice the present procedure to the actual analysis of floors of typical buildings is also emphasized.