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931.
Abstract

We tested some of the key predictions of processing efficiency theory using a simulated rally driving task. Two groups of participants were classified as either dispositionally high or low anxious based on trait anxiety scores and trained on a simulated driving task. Participants then raced individually on two similar courses under counterbalanced experimental conditions designed to manipulate the level of anxiety experienced. The effort exerted on the driving tasks was assessed though self-report (RSME), psychophysiological measures (pupil dilation) and visual gaze data. Efficiency was measured in terms of efficiency of visual processing (search rate) and driving control (variability of wheel and accelerator pedal) indices. Driving performance was measured as the time taken to complete the course. As predicted, increased anxiety had a negative effect on processing efficiency as indexed by the self-report, pupillary response and variability of gaze data. Predicted differences due to dispositional levels of anxiety were also found in the driving control and effort data. Although both groups of drivers performed worse under the threatening condition, the performance of the high trait anxious individuals was affected to a greater extent by the anxiety manipulation than the performance of the low trait anxious drivers. The findings suggest that processing efficiency theory holds promise as a theoretical framework for examining the relationship between anxiety and performance in sport.  相似文献   
932.
Abstract

In this study, we wished to investigate the factors that determine the direction of the spin axis of a pitched baseball. Nineteen male baseball pitchers were recruited to pitch fastballs. The pitching motion was recorded with a three-dimensional motion analysis system (1000 Hz), and the orientations of the hand segment in a global coordinate system were calculated using Euler rotation angles. Reflective markers were attached to the ball, and the direction of the spin axis was calculated on the basis of their positional changes. The spin axis directions were significantly correlated with the orientations of the hand just before ball release. The ball is released from the fingertip and rotates on a plane that is formed by the palm and fingers; the spin axis of the ball is parallel to this plane. The lift force of the pitched baseball is largest when the angular and translational velocity vectors are mutually perpendicular. Furthermore, to increase the lift forces for the fastballs, the palm must face home plate.  相似文献   
933.
Abstract

Pedometers have been identified as a tool for health professionals to promote physical activity. This study, which aimed to evaluate the effectiveness of wearing a pedometer on general practitioners' attitudes to promoting physical activity, was a pragmatic, multi-centred, randomized controlled trial within a primary care trust in England. The participants were 102 general practitioners (GPs). Eighty-five (48 males, 37 females) of the GPs completed pre and post questionnaires, 43 of whom were in the intervention group. Statistical analysis revealed no significant changes between the control and intervention groups for attitude to engage in physical activity (t 83 = 1.13, CI ?0.362 to 0.099) or attitude to promote physical activity in their patients (t 83 = 1.7, CI ?0.593 to 0.045). A higher volume of walking was significantly correlated with a more positive attitude to engage in physical activity (r = 0.58, P < 0.01) but not with a more positive attitude to promoting physical activity. Wearing a pedometer had no significant effect on GPs' attitudes to engaging in physical activity or promoting physical activity in their patients.  相似文献   
934.
Abstract

The purpose of this study was to compare moment-to-moment appraisals and coping strategies of 4 non-elite and 2 elite male trap shooters during competitions and in particular during periods of competition perceived as critical to performance. Appraisals and coping patterns of trap shooters were captured via verbal reports of thinking provided between sets of shots during major competitions. Verbal reports were coded according to an appraisal and coping typology. Coded data as well as shooting performance data were subjected to a sequential analysis of probabilities of pairs of events. Fewer reports of negative appraisals (NEGAs) and more frequent reports of problem-focused coping (PFC) were observed among both elite athletes compared to non-elite athletes. After making a NEGA, non-elite shooters often progressed to the next target without attempting to cope, whereas elite shooters used both PFC and emotion-focused coping (EFC) before proceeding to the next target. After missing a target, the non-elite athletes used more EFC than expected. These results indicate that elite athletes are more likely to cope with NEGAs than non-elite athletes using a wider variety of coping strategies. Athletes might benefit from increased awareness of the potentially detrimental impact of NEGAs on performance and by integrating coping strategies within preparatory routines.  相似文献   
935.
Abstract

The aim of the current study was to investigate the validity and reliability of a radio frequency-based system for accurately tracking athlete movement within wheelchair court sports. Four wheelchair-specific tests were devised to assess the system during (i) static measurements; (ii) incremental fixed speeds; (iii) peak speeds; and (iv) multidirectional movements. During each test, three sampling frequencies (4, 8 and 16 Hz) were compared to a criterion method for distance, mean and peak speeds. Absolute static error remained between 0.19 and 0.32 m across the session. Distance values (test (ii)) showed greatest relative error in 4 Hz tags (1.3%), with significantly lower errors seen in higher frequency tags (<1.0%). Relative peak speed errors of <2.0% (test (iii)) were revealed across all sampling frequencies in relation to the criterion (4.00 ± 0.09 m · sˉ1). Results showed 8 and 16 Hz sampling frequencies displayed the closest-to-criterion values, whilst intra-tag reliability never exceeded 2.0% coefficient of variation (% CV) during peak speed detection. Minimal relative distance errors (<0.2%) were also seen across sampling frequencies (test (iv)). To conclude, the indoor tracking system is deemed an acceptable tool for tracking wheelchair court match play using a tag frequency of 8 or 16 Hz.  相似文献   
936.
Abstract

This study focused on the differences between experienced and inexperienced physical education teachers' approaches to planning, low inference indicators of teaching behavior during instruction, and global variables from the Beginning Teacher Evaluation Study. It was found experienced teachers asked many more questions before they began planning than did inexperienced teachers. Experienced teachers' plans reflected a concern about contingencies that might arise during instruction, whereas inexperienced teachers' plans did not. Interaction analysis and codings of student engagement showed marked differences between experienced and inexperienced teachers. Judging the qualities of experienced and inexperienced teachers also showed important differences. These sources of data are interrelated and give a vivid picture of how experienced and inexperienced teachers differ in accomplishment of instruction. The findings are discussed in terms of what they may mean for teacher development programs.  相似文献   
937.
938.
Abstract

The relationship between organ weight and swimming capacity was determined in 42 male albino rats. Upon completion of a 4-week training program, the animals were forced to swim to exhaustion with 2 percent of the body weight attached. They were sacrificed and specific gravity and organ weights determined. The results warrant the following conclusions: A significant (p < .05) but low correlation exists between the relative weight of the spleen and lungs with swimming performance. The correlation of relative heart weight and swimming performance approached statistical significance (p < .06). Attaching a weight proportional to the body weight to increase the energy cost of swimming penalizes the heavier animals. Correcting for the inverse relationship between body weight and swim time does not alter appreciably the relationships between organ weights and swim time.  相似文献   
939.
Abstract

The experiment was designed to compare the effects of isometric-isotonic (A), dynamic-overload (B), and free swing (C) exercise programs on the speed and strength of a lateral arm movement The 26 college men in each group—three experimental and one control—were given pre- and post-training speed and strength trials. Each experimental group performed its assigned exercise twice a week during the 10-week training period. Reliability coefficients for both strength and speed of movement measurements were found to be high. Following training there were significant speed increases in both the isometric-isotonic and dynamic-overload groups (t=10.06 and 8.10; however, the difference in speed gain between conditions was nonsignificant (F=.10). Also, strength increases in both of these groups were significant (t=8.81 and 3.08), with that of the isometric-isotonic group significantly greater than the dynamic-overload group (F=5.11). No significant speed or strength gains were registered by either the free swing or control group.  相似文献   
940.
Abstract

This study was concerned with the effect of bench-stepping in the Harvard Step Test upon finger and foot reaction time and, secondarily, with ascertaining the relationship, if any, between these reaction times and scores on the Harvard Step Test. The subjects were university freshman males. Reaction times were taken before, immediately after, and four minutes after the stepping exercise for 80 subjects. Thirty-six subjects served as controls, involving the reaction times and pulse counts at the prescribed intervals but without exercise. The findings failed to divulge any discernible effect of stepping exercise upon reaction time, or any apparent relationship between reaction time and the sum of the recovery pulse counts following the exercise. In view of these findings it is suggested that study be directed to two related aspects — the effect of exercise to exhaustion on reaction time, and the effect of strenuous and exhaustive exercise upon speed of movement.  相似文献   
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