Physiological characteristics of successful mountain bikers and professional road cyclists     

Hamilton Lee  David T. Martin  Judith M. Anson  Damian Grundy  Allan G. Hahn 《Journal of sports sciences》2013,31(12):1001-1008

The aims of this study were to compare the physiological and anthropometric characteristics of successful mountain bikers and professional road cyclists and to re-examine the power-to-weight characteristics of internationally competitive mountain bikers. Internationally competitive cyclists (seven mountain bikers and seven road cyclists) completed the following tests: anthropometric measurements, an incremental cycle ergometer test and a 30 min laboratory time-trial. The mountain bikers were lighter (65.3 - 6.5 vs 74.7 - 3.8 kg, P = 0.01; mean - s ) and leaner than the road cyclists (sum of seven skinfolds: 33.9 - 5.7 vs 44.5 - 10.8 mm, P = 0.04). The mountain bikers produced higher power outputs relative to body mass at maximal exercise (6.3 - 0.5 vs 5.8 - 0.3 W·kg -1 , P = 0.03), at the lactate threshold (5.2 - 0.6 vs 4.7 - 0.3 W·kg -1 , P = 0.048) and during the 30 min time-trial (5.5 - 0.5 vs 4.9 - 0.3 W·kg -1 , P = 0.02). Similarly, peak oxygen uptake relative to body mass was higher in the mountain bikers (78.3 - 4.4 vs 73.0 - 3.4 ml·kg -1 ·min -1 , P = 0.03). The results indicate that high power-to-weight characteristics are important for success in mountain biking. The mountain bikers possessed similar anthropometric and physiological characteristics to previously studied road cycling uphill specialists.  相似文献   

石羊河流域地表干湿变化的时空分布特征     

王莺  李耀辉  姚玉璧  赵福年 《资源科学》2013,35(10):2112-2120

利用1960-2011年石羊河流域及周边12个气象站的逐日气象资料,采用FAO Penman-Monteith公式计算研究区各气象站的潜在蒸散发,并由此计算出各站的相对湿润度指数.在ArcGIS 9.3平台下得到区域相对湿润度指数的时空变化特征,并对影响其变化的气象要素进行了探讨.结果表明: 石羊河流域52年来有微弱变干趋势;该区相对湿润度指数自南向北逐渐增加,与降水量和海拔的空间分布比较一致,与潜在蒸散发的空间分布呈相反关系;流域大部分地区的地表相对湿润度指数倾向率呈增加趋势,增加较明显的区域位于祁连山脉附近,呈下降趋势的区域位于上游古浪县附近;流域地表相对湿润度指数在年内呈单峰型变化,1月、11月和12月最低,8月和9月最高,且随气温变暖,自流域南部向北部逐渐推移增大,当气温开始降低时,该指数又从北到南逐渐减少;石羊河流域地表干湿事件的变化与降水量、风速和相对湿度呈正相关,与潜在蒸散发、平均温度和日照时数呈负相关.  相似文献   

数控加工中相对坐标系的应用     

潘建新 《湖南广播电视大学学报》2004,(2):91-92

结合几个应用实例，介绍了相对坐标系在数控加工中的使用技巧。  相似文献   

A Relative Commitment Approach to Understanding Power in Romantic Relationships     

Christopher J. Carpenter 《Communication Studies》2017,68(1):115-130

In some romantic relationships, one partner has more power over joint decisions than the other. This study examines relative commitment as a key predictor of which partner has more power and developed a model based on classic interdependence theory. A survey was conducted (N = 324) using new measures of the key variables to test the model. When desire for control was high, relative commitment predicted self-perceived power, which predicted major and minor decision making as well as dominant conflict strategies. These results are consistent with the proposed modification of interdependence theory concerning desire for control.  相似文献   

关于“线性空间中集合相对内部性质成立的条件”一文的注记     

晏妮 《毕节学院学报》2016,(1):143-147

指出文章“线性空间中集合相对内部性质成立的条件”中的命题4是错误的,并以Banach空间和连续函数空间中的例子说明闭集的仿射包不一定是闭集。  相似文献   

系统相对平衡条件的确定法     

谭青云 《湖南城市学院学报》1995,(6)

本文介绍用拉格朗日法和变分法来确定系统相对平衡的条件，并举例说明其应用．  相似文献   

法治语境下中国死刑问题分析     

王立志 《安阳师范学院学报》2007,1(6):37-41

死刑作为一种刑罚,尽管具有公正性,功利性,但却因不具有人道性而使其自身充满了矛盾,故此其存在仅具有相对合理性。权利话语的兴起和人权事业的蓬勃发展也使得死刑制度逐渐走向自我消亡的结局。现阶段,中国应该逐步限制死刑的适用从而为在中国最终废除死刑创造条件,以顺应时代和法治精神的要求。  相似文献   

黑线姬鼠内脏器官的生长研究     

施时迪 《台州学院学报》1997,(3)

笔者对浙江省临海市郊区农田的黑线姬鼠内脏器官的生长进行了研究。结果表明,根据内脏器官相对重量、绝对重量与胴体重和体长之间的相关性,可将内脏器官的生长方式分成四类。  相似文献   

Colour measurement of acid-detector strips for the quantification of volatile organic acids in storage conditions     

Stephen Hackney 《文物保护研究》2016,61(1):55-69

Acid-detector (A-D) strips were originally developed to assess the deterioration of acetate film stock, but they can also be used more generally within enclosures to detect volatile acidic pollution. A hand-held reflectance spectrophotometer was used to record the colour of individual strips in order to make consistent and reproducible readings. Calibration was carried out using the yellow-blue axis b*(D65) value in the CIELAB1976 system to measure the colour of A-D strips suspended in enclosed containers over solutions of acetic acid in combinations with glycerol to control the relative humidity (RH). A-D strips were found to be sensitive to changes in high RH (60–90%) but affected little by changes in lower RH or temperatures in the museum display and storage range. A-D strips can be used to establish the presence of volatile acids, record the indication of acid vapour concentration, explore conditions within a container, and to find sources of volatile acidity. They respond very quickly and several can be placed around an object. They therefore show promise for measuring slowly changing conditions, such as seasonal changes and the gradual accumulation of acidity in poorly ventilated containers and spaces. A-D strips proved useful in assessing air quality in storage and display enclosures. Examples and test results are presented. Well-sealed plywood transit frames and storage cases were found to be most polluted with volatile acids. Storage rooms with air filtration systems but filled with wooden objects had significantly reduced air quality.  相似文献   

Start hard,finish better: further evidence for the reversal of the RAE advantage     

Neil McCarthy  Dave Collins  David Court 《Journal of sports sciences》2016,34(15):1461-1465

The relative age effect (RAE) has been highlighted extensively within literature as influencing selection and identification within sports. However, this initial bias appears to not be systemic in some talent development systems. Accordingly, we report an investigation into the initial identification, selection and conversion of academy players from professional Rugby Union and Cricket at national level. Reflecting previous studies, data again demonstrated a reversal of RAE advantage whereby relatively young players from both sports were less likely to be selected into their respective national academy systems but were more likely to transition into senior national squads. On the basis of our observations, we further propose a psychological explanation for the mechanism of such a reversal, based on the influence of additional challenge experienced throughout the development journey. As such, we also highlight the need for further qualitative investigation to explore this phenomenon in greater depth.  相似文献