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Cullen, BD, Roantree, M, McCarren, A, Kelly, DT, O'Connor, PL, Hughes, SM, Daly, PG, and Moyna1, NM. Physiological profile and activity pattern of minor Gaelic football players. J Strength Cond Res 31(7): 1811-1820, 2017-The purpose of this study was to evaluate the physiological profile and activity pattern in club- and county-level under-18 (U-18) Gaelic football players relative to playing position. Participants (n = 85) were analyzed during 17 official 15-a-side matches using global positioning system technology (SPI Pro X II; GPSports Systems, Canberra, Australia) and heart rate (HR) telemetry. During the second part of this study, 63 participants underwent an incremental treadmill test to assess their maximal oxygen uptake (V[Combining Dot Above]o2max) and peak HR (HRmax). Players covered a mean distance of 5,774 ± 737 m during a full 60-minute match. The mean %HRmax and %V[Combining Dot Above]O2max observed during the match play were 81.6 ± 4.3% and 70.1 ± 7.75%, respectively. The playing level had no effect on the distance covered, player movement patterns, or %HRmax observed during match play. Midfield players covered significantly greater distance than defenders (p = 0.033). Playing position had no effect on %HRmax or the frequency of sprinting or high-intensity running during match play. The frequency of jogging, cruise running, striding (p = 0.000), and walking (p = 0.003) was greater in the midfield position than in the forward position. Time had a significant effect (F(1,39) = 33.512, p-value = 0.000, and (Equation is included in full-text article.)= 0.462) on distance covered and %HRmax, both of which showed a reduction between playing periods. Gaelic football is predominantly characterized by low-to-moderate intensity activity interspersed with periods of high-intensity running. The information provided may be used as a framework for coaches in the design and prescription of training strategies. Positional specific training may be warranted given the comparatively greater demands observed in the midfield playing position. Replicating the demands of match play in training may reduce the decline in distance covered and %HRmax observed during the second half of match play.
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Fútbol Americano/fisiología , Carrera/fisiología , Adolescente , Rendimiento Atlético/fisiología , Australia , Sistemas de Información Geográfica , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Consumo de Oxígeno/fisiología , Factores de Tiempo , Caminata/fisiologíaRESUMEN
Current knowledge of sensory processing in the mammalian auditory system is mainly derived from electrophysiological studies in a variety of animal models, including monkeys, ferrets, bats, rodents, and cats. In order to draw suitable parallels between human and animal models of auditory function, it is important to establish a bridge between human functional imaging studies and animal electrophysiological studies. Functional magnetic resonance imaging (fMRI) is an established, minimally invasive method of measuring broad patterns of hemodynamic activity across different regions of the cerebral cortex. This technique is widely used to probe sensory function in the human brain, is a useful tool in linking studies of auditory processing in both humans and animals and has been successfully used to investigate auditory function in monkeys and rodents. The following protocol describes an experimental procedure for investigating auditory function in anesthetized adult cats by measuring stimulus-evoked hemodynamic changes in auditory cortex using fMRI. This method facilitates comparison of the hemodynamic responses across different models of auditory function thus leading to a better understanding of species-independent features of the mammalian auditory cortex.
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Corteza Auditiva/anatomía & histología , Corteza Auditiva/fisiología , Gatos/anatomía & histología , Gatos/fisiología , Imagen por Resonancia Magnética/métodos , Animales , Corteza Auditiva/irrigación sanguínea , Hemodinámica , Imagen por Resonancia Magnética/instrumentación , Modelos AnimalesRESUMEN
When conducting auditory investigations using functional magnetic resonance imaging (fMRI), there are inherent potential confounds that need to be considered. Traditional continuous fMRI acquisition methods produce sounds >90 dB which compete with stimuli or produce neural activation masking evoked activity. Sparse scanning methods insert a period of reduced MRI-related noise, between image acquisitions, in which a stimulus can be presented without competition. In this study, we compared sparse and continuous scanning methods to identify the optimal approach to investigate acoustically evoked cortical, thalamic and midbrain activity in the cat. Using a 7 T magnet, we presented broadband noise, 10 kHz tones, or 0.5 kHz tones in a block design, interleaved with blocks in which no stimulus was presented. Continuous scanning resulted in larger clusters of activation and more peak voxels within the auditory cortex. However, no significant activation was observed within the thalamus. Also, there was no significant difference found, between continuous or sparse scanning, in activations of midbrain structures. Higher magnitude activations were identified in auditory cortex compared to the midbrain using both continuous and sparse scanning. These results indicate that continuous scanning is the preferred method for investigations of auditory cortex in the cat using fMRI. Also, choice of method for future investigations of midbrain activity should be driven by other experimental factors, such as stimulus intensity and task performance during scanning.
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Mapeo Encefálico , Imagen por Resonancia Magnética , Corteza Visual/irrigación sanguínea , Estimulación Acústica , Animales , Gatos , Femenino , Procesamiento de Imagen Asistido por Computador , Oxígeno/sangre , Psicoacústica , Corteza Visual/fisiologíaRESUMEN
The purpose of this study was to evaluate the anthropometric characteristics and fitness levels of elite level under 18 (U-18) Gaelic football players to establish normative centile scores for selected fitness parameters and to compare the physical and fitness characteristics relative to each playing position. A total of 265 male U-18 Gaelic football players (age: 16.96 ± 0.7 years; height: 178.11 ± 6.27 cm; weight: 72.07 ± 8.68 kg) participated in the study. According to positional roles, players were categorized as goalkeepers (n = 13), defenders (n = 113), midfielders (n = 30), and forwards (n = 109). Height and weight were measured, and skinfolds were taken before participants sequentially performed a sit and reach test (S&R), countermovement jump (CMJ), standing long jump (SLJ), 5- and 20-m speed test, and the Yo-Yo Intermittent Recovery Test Level 1 (YYIRT1). The percentage body fat was higher (p < 0.01) in goalkeepers than the other playing positions. Goalkeepers had a higher body mass index than defenders (p < 0.05) and forwards (p < 0.01). Midfielders and goalkeepers were taller (p < 0.01) and heavier (p < 0.01) than defenders and forwards. The total distance covered in the YYIRT1 was significantly lower (p < 0.01) in goalkeepers than the other playing positions. There was no significant positional difference in the performance scores in the S&R test, CMJ, SLJ, and 5- and 20-m running speed. The study findings indicate minimal differences in the anthropometric and physiological characteristics between playing positions in elite youth level Gaelic football players. The norm-referenced percentile scores will enable conditioning coaches to benchmark elite performance and design training programs.
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Rendimiento Atlético/fisiología , Aptitud Física/fisiología , Carrera/fisiología , Fútbol/fisiología , Adolescente , Estatura , Peso Corporal , Prueba de Esfuerzo , Humanos , Irlanda , Masculino , Descanso/fisiología , Rol , Grosor de los Pliegues CutáneosRESUMEN
Much of what is known about the cortical organization for audition in humans draws from studies of auditory cortex in the cat. However, these data build largely on electrophysiological recordings that are both highly invasive and provide less evidence concerning macroscopic patterns of brain activation. Optical imaging, using intrinsic signals or dyes, allows visualization of surface-based activity but is also quite invasive. Functional magnetic resonance imaging (fMRI) overcomes these limitations by providing a large-scale perspective of distributed activity across the brain in a non-invasive manner. The present study used fMRI to characterize stimulus-evoked activity in auditory cortex of an anesthetized (ketamine/isoflurane) cat, focusing specifically on the blood-oxygen-level-dependent (BOLD) signal time course. Functional images were acquired for adult cats in a 7 T MRI scanner. To determine the BOLD signal time course, we presented 1s broadband noise bursts between widely spaced scan acquisitions at randomized delays (1-12 s in 1s increments) prior to each scan. Baseline trials in which no stimulus was presented were also acquired. Our results indicate that the BOLD response peaks at about 3.5s in primary auditory cortex (AI) and at about 4.5 s in non-primary areas (AII, PAF) of cat auditory cortex. The observed peak latency is within the range reported for humans and non-human primates (3-4 s). The time course of hemodynamic activity in cat auditory cortex also occurs on a comparatively shorter scale than in cat visual cortex. The results of this study will provide a foundation for future auditory fMRI studies in the cat to incorporate these hemodynamic response properties into appropriate analyses of cat auditory cortex.