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Six male cricket bowlers (mean +/- s(mean): age 23.5 +/- 1.3 years; height 1.83 +/- 0.04 m; body weight 826 +/- 20 N) performed their typical bowling action at a set of stumps positioned at standard pitch length (20.1 m). A specially designed force platform rig allowed the correct positioning of two force platforms to be achieved beneath an outdoor polyflex runway (0.017 m depth) for each player's delivery stride pattern. For the back foot, the peak vertical ground reaction force was 1.95 +/- 0.08 kN (2.37 +/- 0.14 BW) and the braking force was 0.77 +/- 0.12 kN (0.94 +/- 0.16 BW). For the front foot, the peak vertical force was 4.80 +/- 0.92 kN (5.75 +/- 0.98 BW) and the braking force was 2.93 +/- 0.56 kN (3.54 +/- 0.67 BW). The mean peak vertical loading rate for front foot contact was 205 +/- 52.8 kN x s(-1) (249 +/- 64 BW x s(-1)) with mean values ranging from 81 to 446 kN x s(-1) (98 to 540 BW x s(-1)). The range for back foot contact was much smaller, 25-70 kN x s(-1) (30-85 BW x s(-1)), with a mean of 41.7 +/- 7.10 kN x s(-1) (50.6 +/- 8.6 BW x s(-1)). Mean peak impact occurred 24 ms after touchdown for the back foot and 16 ms after touchdown for the front foot. At impact, mean peak loading rates were greater for the front foot at 246 kN x s(-1) (298 BW x s(-1)), with a range of 80-483 kN x s(-1) (98-534 BW x s(-1)), than for the back foot at 65 kN x s(-1) (79 BW x s(-1)), with a range of 40-84 kN x s(-1) (49-110 BW x s(-1)). 相似文献
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Separation of fluoxetine enantiomers on five chiral stationary phases (chiralcel OD-H, chiralcel OJ-H, chiralpak AD-H, cyclobond 1 2000 DM and kromasil CHI-TBB) was investigated. The optimal mobile phase compositions of fluoxetine separation on each column were hexane/isopropanol/diethyl amine (98/2/0.2, v/v/v), hexane/isopropanol/diethyl amine (99/1/0. l, v/v/v), hexane/isopropanol/diethyl amine (98/2/0.2, v/v/v), methanol/0.2% triethylamine acetic acid (TEAA) (25/75, v/v; pH 3.8) and hexane/isopropanol/diethyl amine (98/2/0.2, v/v/v), respectively. Experimental results demonstrated that baseline separation (Rs〉1.5) of fluoxetine enantiomers was obtained on chiralcel OD-H, chiralpak AD-H, and cyclobond I 2000 DM while the best separation was obtained on the last one. The eluate orders of fluoxetine enantiomers on the columns were determined. The first eluate by chiralcel OJ-H and kromasil CHI-TBB is the S-enantiomer, while by chiralpak AD-H and cyclobond 12000 DM is the R-enantiomer. 相似文献
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In the present study, we evaluated the effects of a brief bout of exercise on executive function, short-term memory, and long-term memory tests. Eighteen young adults (mean age 22.2 years, s = 1.6) performed a set-switching test, a Brown-Peterson test, and a free-recall memory test before and after 40 min of moderate aerobic exercise on a cycle ergometer, and two control conditions. Exercise did not facilitate set switching or short-term memory, which suggests that exercise-induced arousal does not influence executive function processes involved in the reconfiguration of information in working memory. Exercise did alter specific aspects of delayed long-term memory. Free recall of items in the primacy and recency portions of the word list declined following the rest and non-exercise conditions, but was maintained after exercise, which suggests that exercise-induced arousal may facilitate the consolidation of information into long-term memory. 相似文献
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Moore DS Ellis R Allen PD Cherry KE Monroe PA O'Neil CE Wood RH 《Research quarterly for exercise and sport》2008,79(1):42-50
The purpose of this study was to establish validity evidence of four physical activity (PA) questionnaires in culturally diverse older adults by comparing self-report PA with performance-based physical function. Participants were 54 older adults who completed the Continuous Scale Physical Functional Performance 10-item Test (CS-PFP10), Physical Activity Scale for the Elderly (PASE), HAMPS Physical Activity Questionnaire for Older Adults, Yale Physical Activity Survey (YPAS), and modified Baecke questionnaire. The total PASE score, three outcome scores for the CHAMPS, and three summary indices for the YPAS were significantly correlated with total CS-PFP10 score. The modified Baecke exhibited no correlations with CS-PFP10 scores. The PASE, CHAMPS, and YPAS appear to be the most valid PA self-report questionnaires for culturally diverse older adults. 相似文献
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Comparison of anthropometry to dual energy X-ray absorptiometry: a new prediction equation for women
The purpose of this study was to assess the accuracy of three recommended anthropometric equations for women and then develop an updated prediction equation using dual energy x-ray absorptiometry (DXA). The percentage of body fat (%BF) by anthropometry was significantly correlated (r = .896-.929; p < .01) with DXA, but each equation underestimated %BF (3.2-5.6 %BF; p < .01). The following DXA criterion (DC) equation was created: %BF= -6.40665 + 0.41946(S3SF) - 0.00126(S3SF)2 + 0.12515(hip) + 0.06473 (age); (S3SF = sum of triceps, suprailiac, thigh; hip = circumference in cm; age = years). The predicted residual sum of squares (PRESS) R2 was high (0.86), and the PRESS standard error of estimate (SEE) was low (2.5 %BF) for our sample of 150 women. The DC equation was further crosschecked on a separate sample of women (n = 25) and again showed excellent agreement. The DC equation appears to be a more accurate estimation of %BF in women. 相似文献
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Parental socialization, vagal regulation, and preschoolers' anxious difficulties: direct mothers and moderated fathers 总被引:1,自引:0,他引:1
Hastings PD Sullivan C McShane KE Coplan RJ Utendale WT Vyncke JD 《Child development》2008,79(1):45-64
Parental supportiveness and protective overcontrol and preschoolers' parasympathetic regulation were examined as predictors of temperamental inhibition, social wariness, and internalizing problems. Lower baseline vagal tone and weaker vagal suppression were expected to mark poorer dispositional self-regulatory capacity, leaving children more susceptible to the influence of parental socialization. Less supportive mothers had preschoolers with more internalizing problems. One interaction between baseline vagal tone and maternal protective overcontrol, predicting social wariness, conformed to the moderation hypothesis. Conversely, vagal suppression moderated several links between paternal socialization and children's anxious difficulties in the expected pattern. There were more links between mothers' self-reported parenting and child outcomes than were noted for direct observations of maternal behavior, whereas the opposite tended to be true for fathers. 相似文献