Análisis de las demandas de Sprint en competición por puestos específicos en el rugby 7 femenino (Analysis of the Sprint demands during competition by playing positions in women’s rugby 7)

Resumen. El objetivo de este estudio es analizar las manifestaciones de sprint, la capacidad de repetir sprint y las posibles diferencias entre los periodos de juego de jugadoras de rugby 7, teniendo en cuenta su puesto específico de juego. Fueron monitorizadas 21 jugadoras (edad 21.2 ± 2.4) agrupadas por puestos específicos: delanteras (n=9; 166.3 ± 12.6 cm; 65.4 ± 7.2 kg) y línea ¾ (n=12; 163.4 ± 9.8cm; 61.7 ± 4.1 kg) en torneos de competición oficial, utilizando un sistema de posicionamiento global (GPS). Para determinar un sprint se consideró umbral individualizado del 61% de la velocidad máxima de cada jugadora. Los resultados muestran que existen diferencias significativas al analizar los grupos de jugadoras (p <.05), en la velocidad máxima (27.0 ± 2.10 vs 24.7 ±1.65), en velocidad máxima en competición (25.9 ± 2.34 vs 21.9 ± 2.59), umbral de sprint (16.4 ± 1.29 vs 15.0 ± 1.0), número de sprint (6.83 ± 1.88 vs 4.54 ± 1.44), distancia recorrida a sprint (166.0 ± 15.64 vs 135 ± 13.94) y sprint repetidos (1.82 ± .76 vs 1.11 ± .31). Se encontraron diferencias significativas entre ambos periodos de juego (p <.05), observándose una disminución considerable en el segundo tiempo de la velocidad máxima en competición, el número de sprints, distancia recorrida a sprint y sprints repetidos. Podemos concluir que el uso de umbrales relativos incrementa el registro del número de sprint. Las diferencias por puestos específicos puede ayudarnos a una mejor comprensión de las demandas de competición y optimizar la planificación del entrenamiento. Abstract. The aim of this study is to analyze sprint demands, the ability to repeat sprints and the possible differences between the playing periods of rugby-7 players, considering their playing position. A total of 21 players (age 21.2 ± 2.4) grouped by specific positions (forwards: n = 9; 166.3 ± 12.6 cm; 65.4 ± 7.2 kg; and backs :n = 12; 163.4 ± 9.8cm; 61.7 ± 4.1 kg) were monitored in official competition tournaments, using a global positioning system (GPS). To determine a sprint, an individual threshold of 61% of the maximum speed of each player was considered. The results show that, when analyzing the group of players (p <.05), there are significant differences in the maximum speed (27.0 ± 2.10 vs 24.7 ± 1.65), in maximum speed in competition (25.9 ± 2.34 vs 21.9 ± 2.59), threshold of sprint (16.4 ± 1.29 vs 15.0 ± 1.0), sprint number (6.83 ± 1.88 vs 4.54 ± 1.44), distance traveled to sprint (166.0 ± 15.64 vs 135 ± 13.94), and repeated sprint (1.82 ± .76 vs. 1.11 ± .31). Significant differences were found between both periods of play (p <.05), observing a considerable decrease of the maximum speed in competition, the number of sprints, distance traveled to sprints, and repeated sprints during the second half. The use of relative thresholds increases the number of sprints. The differences in playing positions can help us to better understand the demands of competition and optimize training planning.

Bootstrap Percolation in Directed Inhomogeneous Random Graphs

Bootstrap percolation is a process that is used to describe the spread of an infection on a given graph. In the model considered here each vertex is equipped with an individual threshold. As soon as the number of infected neighbors exceeds that threshold, the vertex gets infected as well and remains so forever. We perform a thorough analysis of bootstrap percolation on a novel model of directed and inhomogeneous random graphs, where the distribution of the edges is specied by assigning two distinct weights to each vertex, describing the tendency of it to receive edges from or to send edges to other vertices. Under the mild assumption that the limiting degree distribution of the graph is integrable we determine the typical fraction of infected vertices. Our model allows us to study a variety of settings, in particular the prominent case in which the degree distribution has an unbounded variance. As a second main contribution, we quantify the notion of "systemic risk", that is, we characterize to what extent tiny initial infections can propagate to large parts of the graph through a cascade, and discover novel features that make graphs prone/resilient to initially small infections.

Feasibility Study on Fabric-Sheet Unified Sensing Electrode for Non-Contact In-Bed Measurements of ECG, Body Proximity and Respiratory Movement

In a recent article, we have reported that a fabric-sheet unified sensing electrode (FUSE) can detect electrocardiogram (ECG), body proximity at the chest and abdomen (BPxchest, BPxabd) and respiratory movement at the abdomen (RMabd) via worn clothes and bedsheet simultaneously from recumbent human subject. We conducted feasibility study involving 21 subjects to assess the influence of individual difference on this FUSE system. Results revealed that individual difference of physical constitution had little impact on both accuracies of ECG R wave and RMabd under the current FUSE configuration, but had some influence on the voltage changes in BPxchest and BPxabd caused by postural change. We deemed to revise some dimensions of the FUSE to avoid individual threshold setting for sitting up detection.

Individualized thresholds to analyze acceleration demands in soccer players using GPS (Umbrales individualizados para analizar las demandas en la aceleración en futbolistas usando GPS)

The aim of the present study was to analyze the number and the % of maximum accelerations, and the distance covered among different soccer players’ positions, classifying them with GPS technology according to an individual threshold based on the maximum acceleration capacity. 20 players were observed during four matches (n=80). All players undertook a maximal running speed test to determine the maximal acceleration. Players’ activities during the matches were classified into four individual acceleration thresholds: acceleration starting from 0 to 13 km·h-1 and never reaching 18 km·h-1 (A1); acceleration starting from 0 to 13 km·h-1 and reaching 18 km·h-1 (A2); acceleration starting from 13 to 18 km·h-1 (A3); and acceleration starting above 18 km·h-1 (A4). During A1, Full-Backs performed a higher number of accelerations compared to other playing positions and reached a ~95% of the maximum acceleration. During A2, Full-Backs and Wide Midfielder performed a higher number of accelerations than Central Defenders and Forwards, and Central Midfielders reached an estimated intensity of 95% of the maximum acceleration. During A3, CM performed the highest number of accelerations compared to the rest of the groups, while F reached an estimated intensity of 78% of their maximum acceleration. This individualized threshold could help coaches assess players’ physical performance and improve it, or to avoid injuries.Resumen. El objetivo del presente estudio fue analizar el número, % de la aceleración máxima y la distancia recorrida por las diferentes posiciones de juego, clasificándolos según un umbral individual para cada jugador basado en la máxima capacidad de aceleraración usando la tecnología GPS. Un total de 20 jugadores fueron evaluados durante 4 partidos (n=80). Todos los participantes realizaron un sprint a la máxima velocidad de carrera para determinar su capacidad máxima de aceleración. La actividad de los jugadores durante los partidos fue dividida en 4 categorías individuales de aceleración: A1, aceleración de 0 a 13 km·h-1 y sin llegar a 18 km·h-1; A2, aceleración desde 0 hasta 13 km·h-1 y alcanzando 18 km·h-1; A3, aceleración que inicia desde los 13 km·h-1 hasta los 18 km·h-1; A4, aceleración que comienza a una velocidad >18 km·h-1. En A1, los defensas laterales realizaron un mayor número de aceleraciones en comparación con las otras demarcaciones de juego y logrando una intensidad ~ 95% de su aceleración máxima. En A2, los defensas laterales y centrocampistas laterales realizaron un mayor número de aceleraciones que los defensas centrales y delanteros, consiguiendo los centrocampistas una intensidad aproximada del 95% de su máxima aceleración. En A3, los centrocampistas realizaron una cantidad superior de aceleraciones que el resto de grupos, mientras que los delanteros lograron una intensidad aproximada del 78% de su máxima aceleración. Estos umbrales individualizados podrían ser de gran utilidad para permitir evaluar a los técnicos de forma más precisa el rendimiento físico de los jugadores, permitiéndoles con ello mejorar su rendimiento y prevenir lesiones en futbolistas.

Effects of Ear-Canal Static Pressure on Pure-Tone Thresholds and Wideband Acoustic Immittance

Background: Wideband acoustic immittance (WAI) measures provide information about middle-ear function across the traditional audiometric frequency range from 0.25 to 8.0 kHz. Recent studies have found that WAI is effective in predicting the presence of conductive hearing loss (CHL). It is not known whether WAI can accurately estimate the degree of threshold shift caused by CHL. Purpose: The purpose of the present study was to evaluate the relationship between changes in pure-tone threshold and changes in wideband absorbance and acoustic conductance levels induced by positive and negative ear-canal static pressure. Study Sample: Twenty young adult subjects with normal hearing and a negative history of middle-ear disorders participated in the study. Data Collection and Analysis: Experimental pure-tone thresholds at 0.5 and 2.0 kHz were estimated by using a three-interval, three-alternative forced-choice adaptive psychometric procedure under three conditions: ambient ear-canal pressure, +200 daPa static pressure, and −200 daPa static pressure. Wideband absorbance and conductance were obtained in the same subjects by using a Welch Allyn prototype diagnostic middle ear analyzer. Changes in pure-tone threshold from the ambient pressure condition to the static pressure condition were evaluated by using a paired-samples t test and Pearson product-moment correlation. Results: Wideband middle-ear absorbance and conductance at ambient pressure in this study were consistent with published data in adults with normal hearing. The mean change in threshold at 0.5 and 2.0 kHz with +200 daPa or −200 daPa ear-canal static pressure was similar to the mean change in absorbance and conductance levels in the same conditions. However, there was one statistically significant difference between the shift in pure-tone threshold and the change in conductance level for the +200 daPa pressure condition for 2.0 kHz, with the change in threshold being 1.5 dB greater than the change in conductance level (t = 2.39, p = 0.03). In contrast to the good performance of WAI measures in predicting mean threshold shifts caused by ear-canal pressure, the shifts in WAI were not correlated with threshold shifts. Thus WAI was not well suited to predict individual threshold changes caused by ear-canal static pressure. Conclusions: For the conditions of this study, results suggest that mean change in absorbance or conductance level caused by ear-canal static pressure of +200 daPa or −200 daPa provides a good estimate of the change in pure-tone threshold in the same conditions. However, individual threshold change was not accurately predicted by the change in absorbance or conductance level.

Nurses’ perspectives on the suffering of preterm infants

The concept of suffering is discussed among those who are cognitively aware and verbally capable to express their suffering. Due to immaturity, preterm infants’ abilities to express suffering are limited. Relieving suffering is an ethical and juridical demand of good nursing care. The purpose of this study is to describe nurses’ perceptions of the suffering of preterm infants. A descriptive qualitative approach was selected. Data were collected from essays written by nurses (n = 19) working in the neonatal intensive care unit. Inductive content analysis guided by the research question was performed. The nurses described individually determined suffering of the preterm infants according to four categories: suffering ruled by maturation, existence of suffering, individual threshold of suffering and interpreting the cues of suffering. Suffering of preterm infants is manifested by population-specific features, emphasising the need to develop sensitive interventions for relieving their suffering.