Fingertip force and electromyography of finger flexor muscles during a prolonged intermittent exercise in elite climbers and sedentary individuals   总被引：1，自引：1，他引：0  

Vigouroux L  Quaine F 《Journal of sports sciences》2006,24(2):181-186

The aim of this study was to characterize forearm muscle fatigue identified by the decrease in electromyogram median frequency and/or fingertip force during intermittent exercise. Nine elite climbers (international competitive level, USA 5.14a on sight) and ten non-climbers were instructed to maintain a fingertip force of 80% of their maximal voluntary contraction force on a dynamometer mimicking a rock climbing grip during a 5 s effort/5 s rest cycle for 36 repetitions (i.e. 6 min of exercise). Elite climbers lasted twice as long as non-climbers (climbers: 3 min; non-climbers: 1 min 30 s) before the force could no longer be maintained (i.e. the failure point). After this moment, fingertip force decreased and stabilized until the end of the exercise around 50% maximum voluntary contraction force in non-climbers and 63% in elite climbers. Electromyogram median frequency showed a greater decrease in non-climbers than in elite climbers before the failure point. No change in median frequency was observed after the failure point in elite climbers or in non-climbers. These results confirm that elite climbers are better adapted than non-climbers for performing the intermittent fingertip effort before the failure point. After this point, the better fingertip force of elite climbers suggests different forearm muscle properties, while the electromyography results do not provide any indication about the fatigue process.  相似文献   

食物蛋白质——神话还是魔术?     

弗雷德里克·F·安德列斯  利萨·凯纳  黄汉升  黎耀东 《体育与科学》1985,(3)

在体育运动领域里是没有通往金牌的捷径的。献身精神、刻苦训练,良好的基因和有益于中康的饮食就是通往金牌的一切道路。 运动员所使用和误用的所有比赛辅助物中,蛋白质居于大多数误用物质的前列。迎合运动员及  相似文献   

The literary styles of Sir William Osler     

Wallis F 《Osler Library newsletter》1986,(51):1-3

  相似文献   

Harold Segall: a memory renewed     

Wallis F 《Osler Library newsletter》1996,(82):4-5

  相似文献   

Application of derivative ratio spectrophotometry for determination of β-carotene and astaxanthin from Phaffia rhodozyma extract     

Ni H  He GQ  Ruan H  Chen QH  Chen F 《Journal of Zhejiang University. Science. B》2005,6(6):514-522

INTRODUCTION Carotenoids are a class of natural fat-solublepigments generally found in plants, algae, and pho-tosynthetic bacteria, where they play a critical role inthe photosynthetic process. Carotenoids also exist insome non-photo-synthetic bacteria, yeasts, and moldswhere they may carry out a protective functionagainst damages by light and oxygen. Although ani-mals can not synthesize carotenoids within theirbodies, they can intake carotenoids from their dietsleading to bright meat col…  相似文献   

我教书是因为……     

彼得·G·F·德勒 《教师博览》1997,(7)

你为什么非要教书不可?这是我谢绝了担任行政管理职务以后,一位朋友迷惑不解地问的一个问题。几乎所有的美国男孩从小都被灌输长大后要追逐金钱和权力,荣任行政管理职务无疑是朝这个方向前进了一大步,我为什么要拒绝呢? 肯定,我教书不是因为干这一行对我来说容易些。较之我尝试过的几种谋生手段——推土机手、  相似文献   

学习领域和教学组织与安排   总被引：1，自引：0，他引：1  

彼德F.E.斯鲁阿纳 《中国职业技术教育》2002,(11):12-14

目前,教育界人士对职业学校的专业课程各持己见。有人认为职业技术培训过于理论化岸生无法在课堂上学到足够的应用性知识。所以,提出一个以  相似文献   

Peer relations across contexts: individual-network homophily and network inclusion in and after school     

Kiesner J  Poulin F  Nicotra E 《Child development》2003,74(5):1328-1343

Peer relations across 2 contexts (in school and after school) were examined for 577 participants, approximately 12 years old, from 3 middle schools in Milan, Italy. The primary research questions were: Do peer networks from different contexts uniquely contribute to explaining variance in individual behavior? Do measures of peer preference and peer network inclusion across contexts uniquely contribute to explaining individual depressive symptoms? Structural equation models showed that both the in-school and the after-school peer networks uniquely contributed to explaining variance in 2 types of individual problem behavior (in-school problem behavior, after-school delinquency), and that similarity with the 2 peer networks varied according to behaviors specific to each context and across gender. Finally, both in-school and after-school peer network inclusion contributed to explaining variance in depressive symptoms, after controlling for classroom peer preference.  相似文献   

Use of laptop computers in an academic medical library     

Atlas MC  Garza F  Hinshaw R 《Medical reference services quarterly》2007,26(2):27-36

Who borrows laptop computers in an academic health sciences library? Why do they choose to check out laptops? In a survey, laptop computer users responded that the laptops were used most frequently to do class-related work. Laptops were most often checked out because they could be taken to a quiet area of the library or to where the user had more room to work. The majority of such borrowers were satisfied or very satisfied with the laptops and the service from the library. The majority of those completing the survey were medical school students and graduate students. The circulation of laptop computers at this academic health sciences library is a very successful and popular program.  相似文献   

A rapid and accurate 3-（4,5-dimethyl thiazol-2-yl）-2,5-diphenyl tetrazolium bromide colorimetric assay for quantification of bacteriocins with nisin as an example     

Wang F  Cao LT  Hu SH 《Journal of Zhejiang University. Science. B》2007,8(8):549-554

The objective of this study is to propose a more accurate and faster MTT 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r2=0.975±0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125～32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7～8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24～28 h for ADA. The MCA provides an accurate and rapid method for quantifi-cation of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.  相似文献