228 research outputs found
An improved atatistical method for measuring reliability with special reference to rocket engines
Imperial Users onl
An expertise approach to training anticipation using temporal occlusion in a natural skill setting
Anticipation skill was trained through temporal occlusion using vision occlusion spectacles. A with-movement training group had vision occluded as they batted against bowlers, while the without-movement training group’s vision was occluded as they stood behind a net and made a verbal prediction of ball types. Intervention groups and a control group also participated in sports-specific practice. Training benefits, assessed using video simulation and in-situ anticipation tests, were found for the anticipation of short length but not full length deliveries. The with-movement group performed better on the video simulation test than the control group after training. In the in-situ test, both training groups showed improvements from pre- to post-test of foot movements made when vision of ball flight was deprived. This enhanced body positioning translated into an improvement in quality of bat-ball contacts for only the with-movement group. Temporal occlusion training appears to have some selective benefits to improve anticipation expertise
Perceptual strategies of experts and novices in a fast ball sport
This thesis examined the perceptual strategies of expert and novice badminton players in an attempt to test notions of visual selective attention within applied, ecologically valid, sport settings. In keeping with established premises from information-processing theory it was
hypothesized that the expert players would be characterized by a greater ability to extract advance information from the display (to facilitate anticipation), by the allocation of attention to the most pertinent cues available in the display (to promote search efficiency and to avoid distractions) and by the utilization of a relatively low visual search rate (as indicative of processing efficiency).
In Experiment 1 the perceptual strategies of 20 elite and 35 novice badminton players were compared using a series of tasks in which the perceptual display of a badminton player was simulated using film. When the film display was manipulated using variable temporal occlusion points it was found that experts showed a consistently greater ability to predict the landing position of the shuttle from early advance cues than did novices, with the time period between 170 and 85 msec prior to racquet-shuttle contact being a critical one for the establishment of skill group differences. For both skill groups greatest improvements in prediction accuracy arose in the subsequent time period from 85 msec prior to contact to 85 msec after contact implying the criticality of cues arising in this period to the normal decision-making process. When specific spatial cues were selectively occluded from the film display the racquet and the playing side arm were found to be the principal cues upon which experts based their anticipatory prediction of shuttle direction whereas novices appeared to rely only upon racquet cues. These proficiency-related differences in cue usage were capable of explaining, in part, the differences ln anticipatory performance observed on the temporal occlusion task.
Eye movements recorded during the performance of the film task (Experiment 2) were consistent with the notion of the racquet region containing the anticipatory cues of highest informational content with over 70% of all fixations occurring on that section of the display. The visual search sequence was found to normally progress from an early orientation of fixations upon gross bodily features of the opponent (such as trunk, head or lower body) to a later, more precise orientation to the region of the racquet with this apparent proximal-to-distal shift of the fixation distributions matching closely the emergent biomechanical characteristics of the stroke. Both the location and sequence of the fixations however, appeared relatively uninfluenced by the task conditions suggesting that the search patterns adopted were relatively inflexible as if pre-determined by some over-riding perceptual framework. Contrary to some earlier sport-specific investigations of the visual search process no significant differences In fixation location, duration or sequence were observed between experts and novices suggesting that the differences In anticipatory performance observed on the film task were not a consequence of differences In overt visual search characteristics. Advantages of the film task approach over the eye movement recording approach in terms of assessing actual information extraction rather than merely visual orientation were therefore apparent.
Experiments 3 to 7 sought to establish the validity and reliability of the paradigm tor the assessment of individual differences in perceptual strategy used in Experiments 1 and 2. The film task was shown, using dual task methods, to provide comparable attention demands to actually playing and it was shown that concurrent eye movement recording could take place without interference with the subject's response to the film task. Prediction error measures derived from the film task were found to have high reliability with identical conclusions being reached regarding individual subject's perceptual strategies on each occasion the test was administered. Visual search parameters appeared somewhat less reliable with the same anticipatory performance being apparently possible through the use of different search rates, although fixation location and order characteristics remained consistent over time. When the ski II group distinction was reduced and an alternative form of error analysis was adopted the characteristic earlier extraction of information and greater utilization of arm cues by experts again emerged, suggesting that the proficiency-related differences observed in Experiment 1 were robust ones
Disguise and Deception of Action Outcomes Through Sports Garment Design Impair Anticipation Judgments.
The ability to disguise and deceive action outcomes was examined by manipulating sports garments. In Experiment 1, those with higher and lower skill levels in anticipation predicted the throw direction of an opponent who wore a garment designed to disguise kinetic-chain information. Higher skill anticipators were more adversely affected by the disguise garment than the lower skill anticipators, demonstrating that disguise removed the anticipation advantage. In Experiment 2, using the same occlusion methodology, the effect of deception was examined using 2 garments designed to create visual illusions of motion across the proximal-to-distal sequence of the thrower's action and compared with a white-garment control. Performances for the deceptive garments were reduced relative to the control garment at the earliest occlusion points for the rightmost targets, but this effect was reversed for the leftmost targets at the earliest occlusion point, suggesting that the visual illusion garments were deceiving participants about motion information from the proximal-to-distal sequence of the action
Modified perceptual training in sport:A new classification framework
Objectives: To overview a framework that provides a theoretically-grounded approach to predicting the types of modified perceptual training tasks that will stimulate transfer of improved perceptual skills to sport performance environments. Modified perceptual training (MPT) collectively describes on- or off-field sports training tasks that are specifically designed to develop visual and perceptual-cognitive skill. Traditional training approaches in sport include sports vision training and perceptual-cognitive training, while recently, new technologies have enabled a broad range of additional MPT tools to become available to coaches and athletes. Design: Short literature review and opinion article. Methods: Literature in the fields of sports vision training and perceptual-cognitive training are summarised and contrasted. A selection of emerging MPT technologies are then overviewed. This leads to the identification of three interacting factors of MPT task design that may influence the task's capacity to transfer improved training performance to actual competition: (i) the targeted perceptual function, (ii) stimulus correspondence, and (iii) response correspondence, which are assimilated with key tenets of representative learning design. Results: These three theoretically-grounded differences are adopted to support and justify the structure of the Modified Perceptual Training Framework which sets out predictions for future research to test in order to clarify the transfer effect of MPT tools. Conclusions: The application of the Modified Perceptual Training Framework may assist in future testing, design and selection of beneficial training tools in sport and as such, is predicted to have significant impact in empirical and practical settings
Avaliação do programa de rastreio do cancro do colo do útero na região Alentejo
O cancro do colo do útero é um dos mais frequentes no sexo feminino em todo o
mundo, com impactos diretos na mortalidade e morbilidade associada a esta patologia.
A implementação de medidas de prevenção, nomeadamente de programas de rastreios,
potencia o controlo da doença ainda em fase assintomática, antevendo um tratamento
mais eficaz. O presente estudo analisa os dados referentes ao Programa de Rastreio do
Cancro do Colo do Útero na Região Alentejo e estabelece os seguintes objetivos: i)
monitorizar os parâmetros relativos ao planeamento do rastreio e resultados clínicos
gerais; ii) avaliar os resultados citológicos referentes às primeiras citologias de cada
mulher; iii) avaliar os resultados aos testes de deteção do Vírus Papiloma Humano
(HPV); iv) avaliar a relação entre os resultados citológicos e os testes ao HPV. A
operacionalização deste estudo possibilitou traçar uma primeira panorâmica do rastreio
e avaliar os resultados a partir dos objetivos propostos. Aproximadamente 39% da
população elegível foi rastreada. A presença de alterações celulares foi identificada em
1.5% do total de citologias realizadas num primeiro momento. Estes resultados estão
associados a idades mais baixas, ainda que o grau de severidade da lesão seja mais
elevado com o aumento da idade da mulher. Uma elevada prevalência de infeção por
HPV + foi observada em diagnósticos citológicos referentes a LSIL: Evaluation of Cervical Cancer Screening Program in Alentejo Region
Abstract:
Cervical Cancer is one of the most frequent oncologic diseases in women
worldwide, with direct effects in mortality and morbidity rates related to this disease.
The development of preventive measures, including screening programs, enhances
disease control even in the asymptomatic phase, anticipating a more effective treatment.
This study analyzes data regarding Cervical Screening Program in Alentejo and
establishes the following aims: i) track the parameters related to screening planning and
to general clinical results; ii) evaluate first cytological results of each woman; iii)
evaluate the human papilloma virus (HPV) tests results; iv) evaluate the relationship
between cytologic results and HPV tests. The operationalization of this study enabled us
to draw a first overview of the Screening Program, assessing the main findings,
regarding this study’s aims. About 39% of the eligible population was screened. The
presence of cellular changes was observed in 1.5% of all smear tests performed at first.
These results are associated with younger age, although the degree of lesion severity is
higher with increasing age of the woman. A high prevalence of HPV infection was
observed in cytological diagnostics LSIL
Sport-Specific Practice and the Development of Expert Decision-Making in Team Ball Sports
Assessing decision-making in elite academy footballers using real-world video clips
The aim of this experiment was to investigate whether there were differences in decision-making skills between different age groups (Under 16, 18 and 23) of elite academy footballers on a video-based task of real-life football scenarios. It also explored the relationship between individual performance on the task and the performance of the footballers on the pitch, as rated by three independent expert football coaches. This allowed us to examine whether this task is useful in predicting real-world decision-making skills. The results show that there was a significant difference in response times between response time was statistically significantly lower in U23 compared to U18 and U16 and there was no statistically significant difference between the U16 and the U18 groups, but no significant difference between age groups on the accuracy of response. The under 23 age group responded significantly quicker when compared to the under 18 and under 16 age group most quickly, then the U18, and finally, U16 footballers were the slowest on the task. In terms of comparing coaches' opinion about the players' decision-making skills and players performance on the task, there was a positive correlation between accuracy on the task and general decision-making skills rated by the coaches, suggesting that coaches have a good insight on what players can actually do as. However, coaches ratings of decision-making skills and response times on the task did not correlate suggesting that coaches are not aware of the speed of decision-making, and that this is only measurable by a representative task
Developmental Biographies of Olympic Super-Elite and Elite Athletes: A Multidisciplinary Pattern Recognition Analysis
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