Perception of kinematic characteristics of tennis strokes for anticipating stroke type and direction     

Shim J  Les Carlton G  Kwon YH 《Research quarterly for exercise and sport》2006,77(3):326-339

The purpose of this study was to determine the sources of visual information used by highly skilled tennis players in anticipating their opponent's shots. In Experiment 1, motion analysis of the strokes showed that the relative motion between the racquet and forearm was different between the ground strokes and lobs, but there were no reliable kinematic differences when shot direction was varied. In Experiment 2, 12 skilled tennis players observed the opponent hitting strokes in a normal video or in a point-light display with different segments occluded. Players' anticipation accuracy was not degraded by the use of the point-light display. Occluding the racquet and forearm significantly reduced the participant's ability to determine the type of stroke produced.  相似文献   

幼鸽日益消瘦的问题     

J·P·杜夏尔  刘正光 《环球赛鸽科技》2006,(1)

每年春季,比利时各地的鸽友都在抱怨一种疾病,一般称其为鸽腺病毒病。这究竟是种什么疾病呢?有些科研人员把这种疾病规为圆环病毒 (circovirus),一种极少有人知道的病毒。为了使问题更明确一些,我们把这问题转告了吉恩·皮埃尔·杜夏尔(Jean Pierre Duchatel),他在列日大学兽医系工作。需告诉大家的是,吉恩·皮埃尔·杜夏尔先生也是位鸽友,而且自1974年以来就是鸟类医学系的成员,一直与文德夫格教授(Vindevogel)共事。他们一起深入研究感染鸽子的各类病毒,并为Fort Dodge公司研制了多种疫苗,如 Colombovac PMV(副粘病毒疫苗),Colombovac Pox (鸽痘病毒)和Colombovac Paratyphus (副伤寒病毒)。目前,杜夏尔先生正负责一项由FCI(国际赛鸽联合总会)出资扶植的研究项目,研究可传染给信鸽的圆环病毒。  相似文献   

奥运冠军米斯蒂·海曼的训练特点     

J·R·罗萨尼亚 《体育科研》2003,24(3):62

美国运动员米斯蒂·海曼在悉尼奥运会女子200m蝶泳比赛中击败了该项世界纪录保持者澳大利亚苏珊 ?奥尼尔,爆出了2000年一大新闻。米斯蒂的成功,首先在于确立训练目标:增强肌肉力量,改善身体组成成份。虽然,那时她的体魄已经非常健康、匀称了,体内只有16%的脂肪,但计划要她降到12%。教练员探索她发展肌肉的突破口,为她制订了符合饮食习惯的各组食谱。训练中,主要做带有力量性、平衡性、多关节的和全身的练习,如:下蹲,静力举重,大步行进中的扩胸等练习,以增大肺活量。教练员还为她设计了提高肩后部和上背部的力量、提高腰腹部的力量和改善四头…  相似文献   

Pathogenic Vibrio spp. in the Sea Bream, Sparus sarba     

N.Y.S.Woo  J.M.L.Ling  K.M.Lo 《中山大学学报论丛》1995,(3)

VibriosisisacommonandseriousdiseasecausedbybacterialspeciesofthegenusVibrioinalargenumberofmarinefishes.Thediseaseischaracterisedbygeneralsepticaemia,superficialskinlesionsandextensivehaemorrhages[1].Upuntilaround1980,VibrioanguillarumwastheonlyVibriospecieswhichhadbeenshowntobethecausativeagentofvibriosis.However,recentstudieshaverevealedthatseveralotherVibriospeciessuchasV.alginolyticus,V.ordalli,V.damsela,andV.salmonicchwerealsoPOtentialfishpathogens.V.alginolyticus,V.porahaemolyticusa…  相似文献   

图书馆大趋势：2000年展望   总被引：1，自引：0，他引：1  

凯拉斯  E 田宏 《国外图书情报工作》1991,(2):1-7

  相似文献   

青少年参加体育训练运动处方运动负荷水平的研究     

崔巴特尔贾富池  胡晓彦 《少年体育训练》2006,(5):11-11

一、不同年龄阶段的青少年适宜运动负荷水平的判断1对于正处在生长发育阶段的儿童少年而言,由于在进行运动的过程中对氧的需要量大、能量的动用受到一定的限制,其大强度运动中的工作能力不如成人。有研究表明,在进行3m in最大强度运动时,假如20～30岁成人的工作能力为100%,那么9岁少儿的工作能力仅为成人的40%,12岁为69%,15岁为90%。2儿童、青少年的最大氧债的承受能力较差,并且有明显的阶段性和性别差异。表现为男性:7～8岁小于1/6;9～10岁约为1/4;11～12岁约为1/3;13～15岁可达到2/3(进入高增长期,每年分别递增10%、14%);16～18岁可达到3/…  相似文献   

感悟、鉴赏和探究：文学作品教学的三种重要方法——关于文学作品教学的几点浅思     

周红阳． 《教学月刊》2004,(11):9-12

笔者以为，文学作品教学与非文学作品教学有许多共通之处，当以“文本”为依托、“语言”为核心、“理解”为基础、“能力”为目标，换言之，要紧扣文本，揣摩语言，理解内容，发展能力。但“以艺术形象的方式对以人为中心的社会生活的整体作审美反映”㈨是文学与其他社会科学的主要区别，可见文学的特点在于形象和审美，故文学作品的教学又必须通过对形象的感悟(体验)、鉴赏(品味)和探究(发现)等方式，以达到培养和提升学  相似文献   

The relationship between peak height velocity and physical performance in youth soccer players   总被引：1，自引：1，他引：0  

Philippaerts RM  Vaeyens R  Janssens M  Van Renterghem B  Matthys D  Craen R  Bourgois J  Vrijens J  Beunen G  Malina RM 《Journal of sports sciences》2006,24(3):221-230

Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time.  相似文献   

The angiogenetic effect of intramuscular administration of b-FGF and a-FGF on cardiac muscle: the influence of exercise on muscle angiogenesis     

Efthimiadou A  Asimakopoulos B  Nikolettos N  Giatromanolaki A  Sivridis E  Lialiaris TS  Papachristou DN  Kontoleon E 《Journal of sports sciences》2006,24(8):849-854

Although angiogenetic therapy using recombinant growth factors holds much hope for the treatment of ischaemic diseases, there are still many unanswered questions, including the method of administration, the correct dose of these factors, and the duration of the therapeutic approach. Exercise has also been suggested to induce neovascularizaiton in muscles. We evaluated the angiogenetic effects of the intramuscular administration of basic-fibroblast growth factor (b-FGF) and acidic-fibroblast growth factor (a-FGF) in rat heart, compared with rats who exercised daily. In conclusion, both the intramuscular administration of b-FGF and exercise increased significantly angiogenesis in the heart in contrast to the intramuscular administration of a-FGF, which was ineffective.  相似文献   

将健身运动进行到底     

布莱恩·J.萨克 《出版参考》2003,(15)

要想将新采纳的健身运动坚持下去是很困难的。有50％的人在参加健身的第一年就打了退堂鼓。根据泰勒和米勒的理论,有些特定的方法可以用来弥补成功的差距。健身运动是可以得以继续  相似文献