A robust numerical framework for the analysis of material failure of fibre reinforced soft tissue

In this work, robustness and stability of continuum damage models applied to material failure in soft tissues are addressed. In the implicit damage models equipped with softening, the presence of negative eigenvalues in the tangent elemental matrix degrades the condition number of the global matrix, leading to a reduction of the computational performance of the numerical model. Two strategies have been adapted from literature to improve the aforementioned computational performance degradation: the IMPL-EX integration scheme [Oliver,2006], which renders the elemental matrix contribution definite positive, and arclength-type continuation methods [Carrera,1994], which allow to capture the unstable softening branch in brittle ruptures. The IMPL-EX integration scheme has as a major drawback the need to use small time steps to keep numerical error below an acceptable value. A convergence study, limiting the maximum allowed increment of internal variables in the damage model, is presented. Finally, numerical simulation of failure problems with fibre reinforced materials illustrates the performance of the adopted methodology

Planning the contents of training in early age basketball teams

El objetivo del presente trabajo es conocer cómo es el proceso de entrenamiento de baloncesto en categorías de iniciación. De forma específica cómo se planifican los contenidos de este deporte a lo largo de una temporada deportiva. Para ello se analizaron las tareas de entrenamiento planificadas por un entrenador que realiza su labor en un equipo de iniciación al baloncesto. Se examinaron 846 tareas de entrenamiento correspondientes a dos temporadas. Todas las sesiones de entrenamiento se introdujeron en el programa PYC-Basket, para cuantificar el entrenamiento. Las variables del estudio fueron los contenidos de entrenamiento y medios de entrenamiento. Se realizó un primer análisis descriptivo de los datos para conocer cómo es el proceso de planificación. Posteriormente, se realizó un análisis inferencial para estudiar la relación entre las dos variables y profundizar en la forma en que se plantea el desarrollo de cada contenido. La planificación y registro de los elementos que definen la situación de entrenamiento permitió el control de la programación de los contenidos de entrenamiento. Los resultados muestran un predominio de los contenidos técnicos, en concreto de los gestos individuales de ataque. Igualmente los contenidos evolucionan en su tratamiento durante las temporadas analizadas. Los gestos técnico-tácticos individuales se incrementan a lo largo de la temporada. Las conductas táctico-técnicas individuales se van reduciendo conforme se incrementan las conductas táctico-técnicas grupales y colectivas. En las tareas planificadas se combina la utilización de medios como los ejercicios y los juegos para el entrenamiento de cada tipo de contenido. Se emplean los ejercicios para desarrollar la técnica y los juegos para la táctica.The aim of this study was to determine how basketball process training was in initation stage. Specifically how to plan the contents of this sport over a season. For that, training activities planned by a coach who performed their work in a initation team were analyzed. 846 training activities for two seasons were studied. All training sessions were introduced in the PYC-Basket program to quantify the training. The study variables were the contents of training and media training. An initial descriptive analysis of the data to understand how the planning process was carried out. Subsequently, an inferential analysis was performed to study the relationship between two variables and examine the way it presents the development of each content. The planning and recording of the elements that define the coaching situation allowed the control of the programming content of training. The results show a predominance of technical contents, particularly of the individual gestures of attack. Contents also evolve in their treatment during the analyzed seasons. The individual technical and tactical gestures increase over the season. The individual technical and tactical behaviors were reduced with increasing tactical behaviors and collective group techniques. In the planned tasks, the use of means such as exercises and training games for each type of content were combined. Exercises were used to develop the technique and tactics games.peerReviewe

Incidence of type of game mode in player participation in minibasket

Young basketball players have unique development features that make it necessary to adapt the competition techniques to them. Minibasket competition must provide a high level of participation, many 1-on-1 situations and opportunities to shoot and score. The aim of this research was to compare, in Benjamin minibasket players (aged between 8 and 10 years old) in Extremadura, the competition game mode 4-on-4 with the 3-on- 3 game mode and to compare how player ́s participation is in each game mode. The design of this research is classified as an empirical study with quantitative methodology, with an independent variable and random groups. Results showed that in 3-on-3 game mode, a significantly higher number of possessions and 1-on-1 situations were produced as well as more efficient at the end of possessions than in the 4-on-4 game mode (p < .05). Furthermore, weighted average (weighted by the number of players who play for each team) of players ́s contacts with the ball and players involved in each possession suggested a greater participation in the 3-on-3 game mode. According to these results, it was concluded that the 3-on-3 game mode is more formative and adapted to the features of minibasket players in Benjamin category.Los jugadores jóvenes de baloncesto tienen unas características evolutivas propias que hacen necesario que la competición sea debidamente modificada para ajustarse a las mismas. La competición en minibasket debe proporcionar un alto nivel de participación además de un número elevado de situaciones de 1 contra 1 y de oportunidades de lanzar a canasta y anotar. El propósito del presente estudio fue comparar, en jugadores de minibasket de categoría benjamín (8-10 años), la modalidad de juego de competición de 4 contra 4, con una modalidad de juego más reducida, el 3 contra 3, para estudiar la incidencia que el número de jugadores tiene sobre la participación de estos en el juego. El diseño de esta investigación se clasifica como un estudio empírico con metodología cuantitativa, con una variable independiente y grupos aleatorios. Los resultados mostraron que en la modalidad de 3 contra 3 se produjeron un mayor número de posesiones de los equipos y de situaciones de 1 contra 1 así como una mayor eficacia en la finalización de las posesiones de forma significativa (p < .05) respecto a la modalidad de 4 contra 4. Además, las medias ponderadas del número de contactos por posesión y del número de jugadores que entran en contacto con el balón por cada posesión sugieren que hay una mayor participación de los jugadores en la modalidad de 3 contra 3. Sobre la base a estos resultados se concluye que la modalidad de 3 contra 3 es más formativa y adaptada a las características de los jugadores de minibasket en categoría benjamín

Differences in basketball training loads between comprehensive and technical models of teaching/training

Researchers analyze differences between models of sport training in order to identify the most suitable one. In basketball studies are focused on finding out differences amongst the processes of sport learning and taking decisions. The basketball training load includes the total sum of stimulus to which players are subjected during the preparation process. The aim of this research was to identity differences in training loads amongst the different tasks designed by basketball coaches who used different comprehensive and technical models of teaching/training. Two expert coaches of each training model participated in the study. All tasks performed during 10 training sessions were analyzed. In each task several aspects were studied: opposition, density/intensity, number of performers, competitive load, game area, cognitive involvement, mean heart rate, total time and useful time of the task. After that, the load of the task, value of training, and utilization of the task were calculated. There are statistically significant differences (p < .05) between the proposed tasks under the Comprehensive and Technical Model in the level of opposition, the number of performers, the load of the task, total time, useful time and utilization of tasks. The Comprehensive Model of training increases training load compared to the Technical Model, increasing the level of opposition and the number of players participating in the tasks. It also provides better utilization of tasks. The training process is more effective in practice time under the comprehensive model.Los investigadores analizan las diferencias entre los modelos de entrenamiento deportivo para identificar cual es el más idóneo. En baloncesto los estudios se orientan a descubrir las diferencias en el aprendizaje deportivo y en la toma de decisiones. La carga de entrenamiento en baloncesto se considera como la suma total de estímulos a los que el jugador se ve sometido durante el proceso de preparación. El objetivo de esta investigación fue identificar la existencia de diferencias en la carga de entrenamiento en las tareas diseñadas por entrenadores de baloncesto posicionados en modelos de entrenamiento-aprendizaje comprensivo y técnico. Participaron en el estudio dos entrenadores expertos posicionados en cada uno de los modelos de entrenamiento. Se examinaron las tareas realizadas durante 10 sesiones de entrenamiento. En cada tarea se analizó el grado oposición, densidad/intensidad, número de ejecutantes, carga competitiva, espacio de juego, implicación cognitiva, frecuencia cardíaca media, tiempo total y tiempo útil de la tarea. Posteriormente se calculó la carga de la tarea, valor del entrenamiento, y el aprovechamiento de la tarea. Existen diferencias estadísticamente significativas (p < .05), entre las tareas propuestas bajo el Modelo Comprensivo y Técnico en el grado de oposición, el número de ejecutantes, la carga de la tarea, tiempo total, tiempo útil y el aprovechamiento de las tareas. El Modelo Comprensivo de entrenamiento incrementa la carga de entrenamiento frente al Modelo Técnico, al aumentar el grado de oposición y el número de jugadores que participan en las tareas. Además, ofrece un mayor aprovechamiento de las tareas. El proceso de entrenamiento es más eficaz en el tiempo de práctica bajo el modelo comprensivo

Coherent structures and bubble-particle velocity in 2-D fluidized beds

This work presents an experimental study to characterize ascending bubbles and granular velocity in the dense phase of a 2-D fluidized bed. Three different non-intrusive techniques based on images obtained with a high speed camera are developed, and applied to the images. First the bubble paths are characterized with time-average concentration maps and the bubble velocities are obtained, using a tracking algorithm over the mass centers of the bubbles. Finally, a PIV (particle image velocimetry) method is used to characterize the particle velocity vectors. This procedure is repeated for different bed aspect ratios, and different superficial gas velocities. This study analyzes the superficial gas velocity influence on the bed behavior, and how the bubble path configuration depends on the bed aspect ratio. The PIV measurements give us information on the location of the recirculation regions and the influence of the superficial gas velocity.Publicad

Differential Effects of Simulated Neural Network's Lesions on Synchrony and EEG Complexity

Brain function has been proposed to arise as a result of the coordinated activity between distributed brain areas. An important issue in the study of brain activity is the characterization of the synchrony among these areas and the resulting complexity of the system. However, the variety of ways to define and, hence, measure brain synchrony and complexity has sometimes led to inconsistent results. Here, we study the relationship between synchrony and commonly used complexity estimators of electroencephalogram (EEG) activity and we explore how simulated lesions in anatomically based cortical networks would affect key functional measures of activity. We explored this question using different types of neural network lesions while the brain dynamics was modeled with a time-delayed set of 66 Kuramoto oscillators. Each oscillator modeled a region of the cortex (node), and the connectivity and spatial location between different areas informed the creation of a network structure (edges). Each type of lesion consisted on successive lesions of nodes or edges during the simulation of the neural dynamics. For each type of lesion, we measured the synchrony among oscillators and three complexity estimators (Higuchi’s Fractal Dimension, Sample Entropy and Lempel-Ziv Complexity) of the simulated EEGs. We found a general negative correlation between EEG complexity metrics and synchrony but Sample Entropy and Lempel-Ziv showed a positive correlation with synchrony when the edges of the network were deleted. This suggests an intricate relationship between synchrony of the system and its estimated complexity. Hence, complexity seems to depend on the multiple states of interaction between the oscillators of the system. Our results can contribute to the interpretation of the functional meaning of EEG complexity. </jats:p

¿Baloncesto sin fronteras? Similitudes y diferencias entre los Campeonatos Continentales de baloncesto

El estudio de los indicadores de rendimiento técnico-tácticos son una gran herramienta para los entrenadores, pues proporciona información objetiva sobre las acciones del deportista y del equipo. El objetivo de esta investigación fue estudiar los indicadores de rendimiento en los últimos Campeonatos Continentales de Baloncesto. Se analizaron los 5 campeonatos continentales del año 2015, un total de 231 partidos. Las variables analizadas fueron: posesiones de balón, diferencia de puntos, puntos anotados, lanzamientos de uno, dos y tres puntos anotados y lanzados, rebotes totales, defensivos y ofensivos, asistencias, robos, pérdidas, tapones a favor y en contra, faltas cometidas y recibidas, y valoración. Se llevaron a cabo un análisis descriptivo y de perfiles de rendimiento para caracterizar la muestra. La ANOVA de un factor con la corrección de Bonferroni se utilizó para identificar las diferencias entre campeonatos. El análisis discriminante permitió identificar los indicadores de rendimiento que mejor caracterizan a cada uno de los campeonatos continentales. Los resultados ponen de manifiesto que existen diferencias entre todos los campeonatos en todos los indicadores de rendimiento, salvo en los tiros de 3 puntos anotados y en los tapones. Se identifica un perfil de juego específico para cada campeonato. Las mayores diferencias en los perfiles de rendimiento se encuentran entre el Eurobasket y Africabasket, mientras que los campeonatos con un perfil más parecido en los indicadores de rendimiento son el FIBA América y Asiabasket. Estos hallazgos son de utilidad para los entrenadores a la hora de preparar los diferentes escenarios posibles en función del campeonato y rival al que se enfrenten.The analysis of technical-tactical performance indicators is an excellent tool for coaches, because it provides objective information on the actions of players and teams. The aim of this investigation was to study the performance indicators for the last continental basketball championships. Five continental championships played in 2015 were analysed for a total of 213 matches. The variables analysed were: ball possessions, point difference, points scored, one, two and three point throws attempted and scored, total and defensive and offensive rebounds, assists, steals, turnovers, blocks for and against, fouls committed and received, and evaluation. A descriptive analysis and performance profiles were carried out to characterise the sample. A one-way ANOVA and Bonferroni correction were used to identify the differences among championships. A discriminant analysis was performed to identify the performance indicators best characterising each analysed championship. The results show that there are differences among all the championships and all the performance indicators, except in three point throws scored and blocks. A specific play profile has been identified for each championship. The greatest performance profile differences were found between the Eurobasket and the Afrobasket championships, while the championships with the most similar performance indicator profiles were FIBA America and Asia Cup. These findings are useful for coaches when preparing the different possible scenarios depending on the championship and their respective opponent.• Junta de Extremadura y Fondos FEDER. Ayuda GR15122peerReviewe

Scoring coordination patterns in basketball international championships of national teams

The performance of two basketball teams can be analysed by exploring their different scoring dynamics on the basis of the two time series representing the scoring process of each team throughout the game. Existing studies following this approach focused mainly on regular season and playoff games in different basketball leagues. The aim of this study was to conduct this type of analysis on games of National Teams championships, focusing specifically on final round close games, as those in which medals are decided and teams perform in a very similar level. The study considers the final round games (i.e. semi-finals games, third-place game and final game) of the main men's professional basketball International Championships of National Teams (i.e. European Championships, World Championships and Olympic Games) played during the period 2005-2013. Different methods of time series analysis were used (i.e. autocorrelation and cross-correlation functions, double backward moving averages, Hilbert transform). The results revealed an increasing scoring coordination pattern between the teams as the games unfolded, showing extremely high coordinated behaviours in the 3rd and 4th quarters (i.e. similar scoring streaks by the two teams; back-and-forth scoring patterns). This suggests that are the first two quarters of the games those leading to major fluctuations on the scoreboard (i.e. game periods in which one team's scoring performance is very successful whilst the other team's is not). This study may be matter of interest to coaches and performance analysts in the field of basketball, providing practical information for specific games preparations in International Championships of National Teams.El rendimiento de dos equipos de baloncesto se puede analizar mediante la exploración de sus diferentes dinámicas de anotación sobre la base de las dos series temporales que representan el proceso anotador de cada equipo durante todo el partido. Los estudios existentes siguiendo este enfoque se han centrado principalmente en partidos de temporada regular y de playoff en diferentes ligas de baloncesto. El objetivo de este estudio fue llevar a cabo este tipo de análisis en partidos de campeonatos de selecciones nacionales, centrándose específicamente en los partidos ajustados de las rondas finales, como aquellos en los que se deciden las medallas y en los que los equipos desempeñan en un nivel muy similar. El estudio considera los partidos de las rondas finales (semifinales, tercer y cuarto puesto, y final) de los principales campeonatos internacionales de baloncesto de selecciones nacionales en categoría masculina (Campeonatos Europeos, Campeonatos del Mundo y Juegos Olímpicos) disputados durante el período 2005-2013. Se utilizaron diferentes métodos de análisis de series temporales (funciones de autocorrelación y correlación cruzada, doble media móvil, transformada de Hilbert). Los resultados revelaron un patrón creciente de coordinación anotadora entre los equipos a medida que los partidos avanzaban, mostrando patrones de coordinación extremadamente altos en el tercer y último cuarto (rachas de anotación similares para los dos equipos, patrones de anotación de ida y vuelta). Esto sugiere que son los dos primeros cuartos de los partidos aquellos que conducen a mayores fluctuaciones en el marcador (períodos de juego en los que el rendimiento anotador de un equipo es muy exitoso, mientras que el del otro equipo no lo es). Este estudio puede ser de interés para los entrenadores y analistas de rendimiento en baloncesto, proporcionando información práctica para la preparación específica de partidos en los campeonatos internacionales de selecciones nacionales

Editorial: performance analysis in sport

Performance analysis is a sub-discipline of Sport Science research (Borms, 2008) that has attained great interest for many stakeholders (i.e., coaches, technical staff, performance analysts, managers, media, fans, and players) at different levels of performance (i.e., youth, semiprofessional, or professional players). The development and implementation of new technologies to measure individual or team’s performances (e.g., tracking systems such as local positioning systems, LPS; video tracking, or observational video analysis systems) with multiple practical applications have intensified the focus of performance analysis in sport (Hughes and Franks, 2007). Traditional approaches have included static analysis focused on retrospective performances; however, dynamic and complex analyses (i.e., non-linear Multi-Dimensional Scaling, classification and regression tree, logistic regression, etc.) have become increasingly utilized by researchers for a deeper understanding of sport performance during training and competition (O’Donoghue, 2009). In particular, a holistic and multidisciplinary perspective such as the Grand Unified Theory analyses (GUT, see Glazier, 2017) has been suggested to be fundamental for sports performance. This approach, provides a framework to examine the inter- and intra-athlete’s behavior dimensions under the environmental and task-related (ecological) factors that affect the performance. Specifically, isolated approaches have been suggested to be avoided with the integration of the biomechanical, physiological, psychological, technical, tactical, positional, motor development and/or strength and conditioning perspectives recommended when evaluating match-related contexts and training tasks (Glazier, 2017). Additionally, Woods et al. (2020) highlighted the importance of ecological dynamics to guide the control, preparation and assessment of athletes and teams. Subsequently, the use of interdisciplinary research designs would provide clear and well-described rationales, powerful data collection and analyses, resulting in robust findings. Innovative sports performance analyses that incorporate new technologies to understand individual’s behaviors within real-based and ecological contexts would provide a greater understanding of how players and teams act and react for greater performance development and application (Bertollo et al., 2020). In fact, as Robertson (2020) argued, the development of professionalism and data gathering in sport had lead to a new scenario for coaching staff, athletes, and performance analysts where adaptative tools are essentially required to understand the needs of sports performance (e.g., human-machine interaction, perspective, innovation, versatility, visualization, evaluation, feedback, generalization, and future planning