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991.
Patterns of perceptual deficits were investigated in a population of academically deficient juvenile delinquents. Comparisons were made with a group of youthful offenders with adequate academic skills. Auditory perceptual deficits appeared to be a more significant factor in accounting for the severe academic deficiencies observed in the delinquent subjects than did visual-perceptual deficits. However, multiple perceptual deficits involving both auditory and visual perceptual skills formed the basis of the majority of academic deficiencies and social maladaptation. The results indicate the potential ill effects of an undiagnosed and untreated learning disability on subsequent emotional development. Prevention of delinquency may begin with the preschool child who is at high-risk for developing behavioral problems in later years. 相似文献
992.
Laser sailors have to tolerate fatiguing contractions of the lower-body muscles for prolonged periods. The aims of the present study were (1) to evaluate the difference between top-ranked and club sailors, in their capacity to resist fatigue during sustained isometric and maximal power exercise, and (2) to examine the relationships between the above parameters and performance on a Laser simulator and competitive racing performance according to the national ranking list. Eight Greek nationally ranked Laser sailors were compared with eight club sailors. Each sailor performed: (a) an effort to the limit of tolerance on the Laser simulator, (b) an effort to the limit of tolerance of isometric endurance for the right leg on an isokinetic dynamometer, and (c) a Wingate test of maximal lower-body anaerobic power on a cycle ergometer. In the nationally ranked sailors, isometric endurance time (mean 160 s, s = 50) and endurance time on the Laser simulator (1381 s, s = 1354) were significantly (P < 0.05) longer than in the club sailors (101 s, s = 29 and 565 s, s = 367, respectively), whereas the final minute heart rate (in both groups: 149 beats . min(-1), s = 22) and the mean arterial pressure (nationally ranked sailors: 129 mmHg, s = 16; club sailors: 120 mmHg, s = 21) on the Laser simulator were not different between groups. During the Wingate test, the nationally ranked sailors had a significantly lower index of fatigue (42%, s = 5) than the club sailors (49%, s = 6). Isometric endurance time was significantly correlated with the Wingate index of fatigue (r = -0.73; P < 0.001). The nationally ranked sailors' mean and maximal anaerobic powers were significantly correlated with their national ranking positions (r = -0.83 and -0.71, respectively). It is suggested that isometric endurance and anaerobic power are well-developed in Laser class sailors and may influence their sailing performance. Furthermore, compared with club sailors, the nationally ranked sailors are able to sustain the same intensity of lower-limb isometric contractions for much longer with similar cardiovascular responses. 相似文献
993.
Physiological determinants of climbing-specific finger endurance and sport rock climbing performance 总被引:1,自引:1,他引:0
MacLeod D Sutherland DL Buntin L Whitaker A Aitchison T Watt I Bradley J Grant S 《Journal of sports sciences》2007,25(12):1433-1443
The aim of the study was to examine several physiological responses to a climbing-specific task to identify determinants of endurance in sport rock climbing. Finger strength and endurance of intermediate rock climbers (n = 11) and non-climbers (n = 9) were compared using climbing-specific apparatus. After maximum voluntary contraction (MVC) trials, two isometric endurance tests were performed at 40% (s = 2.5%) MVC until volitional exhaustion (continuous contractions and intermittent contractions of 10 s, with 3 s rest between contractions). Changes in muscle blood oxygenation and muscle blood volume were recorded in the flexor digitorum superficialis using near infra-red spectroscopy. Statistical significance was set at P < 0.05. Climbers had a higher mean MVC (climbers: 485 N, s = 65; non-climbers 375 N, s = 91) (P = 0.009). The group mean endurance test times were similar. The force-time integral, used as a measure of climbing-specific endurance, was greater for climbers in the intermittent test (climbers: 51,769 N x s, s = 12,229; non-climbers: 35,325 N x s, s = 9724) but not in the continuous test (climbers: 21,043 N x s, s = 4474; non-climbers: 15,816 N x s, s = 6263). Recovery of forearm oxygenation during rest phases (intermittent test) explained 41.1% of the variability in the force-time integral. Change in total haemoglobin was significantly greater in non-climbers (continuous test) than climbers (P = 0.023--40% test timepoint, P = 0.014--60% test timepoint). Pressor responses were similar between groups and not related to the force-time integral for either test. We conclude that muscle re-oxygenation during rest phases is a predictor of endurance performance. 相似文献
994.
Salo AI Scarborough S 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):155-166
The aim of this study was to understand changes in technique within an athlete's own performance during a sprint hurdles run. Four athletes performed a training session containing four trials each over 10 hurdles. Clearances at hurdles three and nine were videotaped from a side view and manually digitised. All athletes in this study yielded a lower running speed over the hurdle at the ninth hurdle in comparison to the third hurdle in each run. All athletes also showed further signs of potential tiredness in the clearances of the ninth hurdle. Interestingly, these changes in technique varied among the athletes. This poses challenges to coaches, as they need to evaluate individually what changes in training should be introduced to keep the quality of clearances as high as possible throughout training. To match more closely the velocities to those in competitions, consideration could be given in training to shorten gradually the distances between the hurdles more during the latter part of the run, although this should be individually checked, based on the athlete. This way, athletes could learn to clear the hurdle with a higher horizontal velocity, even when fatigue is potentially influencing the performance. 相似文献
995.
Steven I. Pfeiffer 《Psychology in the schools》1980,17(3):346-350
The present study investigated the possible bias of diagnostic labeling on special education placement decisions. Two groups of child study team members were given the task of either placing or both labeling and placing ten exceptional children. Results showed that the labeling process did not lead diagnosticians to place children in more restrictive educational programs. A comprehensive assessment-intervention-follow-through model that would minimize some of the potential dangers and abuses of labeling is proposed. 相似文献
996.
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999.
Objective: To review the principles underlying medical student selection from the perspective of the imperatives of widening access policies. 相似文献
1000.