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901.
The relationship between first name desirability and popularity was studied using 780 boys and 768 girls from six elementary schools. Girls' popularity, as demonstrated by positive sociometric choices, was significantly related to the desirability of their first names. There is also a slight indication that boys' popularity with girls was influenced by the boys' first names. Sociometric rejections were not related to first name desirability for either boys or girls. The findings for girls remained significant when the effects of parental education and ethnicity were partialled out; the single finding for boys did not. 相似文献
902.
We examined variations in dart-throwing performance during the daytime in 12 participants. Two distances from the dartboard were investigated - the normal distance (short throws) and another 50% further away than this (long throws). Intra-aural temperature and subjective fatigue were measured, and errors in performance were assessed as the radial distances of throws from the bulls-eye and the standard deviation of these distances. Long-distance throws improved significantly throughout the daytime and correlated positively with intra-aural temperature (r= -0.49, P=0.002 and r= -0.49, P=0.002 for errors and standard deviation of errors, respectively), but not with subjective fatigue (r= -0.10, P=0.56 and r= -0.05, P=0.74 for errors and standard deviation of errors, respectively). Short-distance throws were associated less with intra-aural temperature (r= -0.46, P= 0.005 and r= -0.17, P=0.31 for errors and standard deviation of errors, respectively), and worsened with fatigue (r=+0.34, P= 0.040 for errors). Compared with the short-distance throws, the long-distance throws were performed significantly less well than could be accounted for by the increased distance (mean errors were increased 1.67-2.78 times and standard deviation of errors of errors 1.58-3.68 times), supporting the concept of a trade-off between force of contraction and accuracy of performance. Throwing darts can be used as a model for investigating factors that influence motor performance, and our results indicate that the effects of time of day upon performance depend upon the relative importance of force and accuracy. 相似文献
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Biomechanical validation of a specific upper body training and testing drill in cross-country skiing 总被引:1,自引:0,他引:1
Stöggl T Lindinger S Müller E 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(1):23-46
The aim of this study was to perform a biomechanical validation of a double poling imitation drill on a rollerboard. Six elite cross-country skiers performed three imitation drill trials at maximal speed at 13 degrees inclination and in double poling on roller skis on a paved road of 3 degrees. Pole and strap forces, elbow and hip angles and EMG activity of eight upper body muscles were measured. Force curves showed similar characteristics, except for impact force occurring only at pole plant in double poling on roller skis. Double poling on a rollerboard includes an eccentric roll-down phase not appearing in double polling on roller skis. Forces on the rollerboard were similar to those on roller skis. Courses of the elbow angles indicated similar shapes, except for the angle at the start of the propulsion phase and, consequently, during flexion (p < 0.01). Propulsion time and cycle duration were longer and frequency lower on the rollerboard (all p < 0.001). Muscle activities were not significantly different, except for stronger biceps brachii (p < 0.01) and weaker erector spinae activation (p < 0.05) on the rollerboard. Muscle coordination patterns showed similar onset and offset points of each muscle and comparable activations in both activities, except for biceps brachii. Two movement strategies on the rollerboard were found, which led to small differences in measured variables. The biomechanical validity of double poling on a rollerboard can be judged as moderately high, being aware of the differences in some variables that might be considered in training sessions on the rollerboard, particularly when using intervals with high number of repetitions. 相似文献
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Are variations in test-preparation practices from school to school undermining the meaningfulness of achievement test results? Is there pressure to raise achievement test scores by the use of educationally unsound practices? What uses of achievement test scores are most common? Do teachers and administrators have reasonably accurate views of test score uses? 相似文献
910.