Postural balance and rifle stability in a standing shooting position after specific physical effort in biathletes     

Dorota Sadowska  Justyna Krzepota  Andrzej Klusiewicz 《Journal of sports sciences》2019,37(16):1892-1898

The aim of the study was to evaluate the effect of maximal specific physical effort on postural balance and rifle stability in biathletes in a standing shooting position. The study included 10 junior elite biathletes. The measurements were taken with the Vicon system and AMTI force platform. Postural balance and rifle stability characteristics were determined at rest as well as 1 and 5 min post maximal specific physical effort which was performed on a ski ergometer and continued until exhaustion. Maximal physical effort exerted a significant effect on all examined postural sway and rifle sway characteristics. The duration of the post-exercise changes was longer than 5 minutes. Higher post-effort rifle sway was observed in the vertical direction than in the across the shooting line direction. Post-effort postural balance impairment in the shooting line was much greater than in the across the shooting line direction. Moreover, a strong correlation was found between postural balance and rifle stability. Maximal physical effort influenced postural balance and rifle stability during aiming. Rifle sway during aiming in a standing shooting position seems to be coordinated with the postural sway of the biathlete’s body. Thus, an increase in postural sway contributes to greater sway and lesser stability of the rifle.  相似文献   

上海女子自行车运动员冲刺骑行中的下肢运动学评价          下载免费PDF全文

何俊良  许以诚  马国强 《体育科研》2018,(2):87-90

对女子短距离自行车运动员45 s全力冲刺骑行进行下肢运动学分析，探讨不同水平运动员速度能力的特点，筛选可评价下肢踏蹬技术的运动学指标。使用三维红外运动捕捉系统及SRM自行车测功仪，采集上海自行车队4名女子短距离运动员场地车滚筒练习台上45 s全力冲刺骑行中的下肢运动学参数和踏频。结果表明，钟××速度能力较好，45 s全力冲刺骑行各阶段平均速度较高，但下肢踏蹬"圆滑度"还需进一步提高；顾××和姚××后程速度下降明显，速度耐力明显不足。在全力冲刺骑行后期，运动水平较高的运动员（钟××）踝关节活动度下降明显小于运动水平较低的运动员（顾××和姚××），提示踝关节活动度下降是影响自行车短距离项目运动员速度耐力的因素之一。  相似文献   

Physical characteristics and resistance parameters of typical urban cyclists     

Simone Tengattini 《Journal of sports sciences》2018,36(20):2383-2391

This study investigates the rolling and drag resistance parameters and bicycle and cargo masses of typical urban cyclists. These factors are important for modelling of cyclist speed, power and energy expenditure, with applications including exercise performance, health and safety assessments and transportation network analysis. However, representative values for diverse urban travellers have not been established. Resistance parameters were measured utilizing a field coast-down test for 557 intercepted cyclists in Vancouver, Canada. Masses were also measured, along with other bicycle attributes such as tire pressure and size. The average (standard deviation) of coefficient of rolling resistance, effective frontal area, bicycle plus cargo mass, and bicycle-only mass were 0.0077 (0.0036), 0.559 (0.170) m², 18.3 (4.1) kg, and 13.7 (3.3) kg, respectively. The range of measured values is wider and higher than suggested in existing literature, which focusses on sport cyclists. Significant correlations are identified between resistance parameters and rider and bicycle attributes, indicating higher resistance parameters for less sport-oriented cyclists. The findings of this study are important for appropriately characterising the full range of urban cyclists, including commuters and casual riders.  相似文献   

城市公共自行车STP策略实证分析     

王从辉  刘玉林 《安阳工学院学报》2016,15(2):76-79

截至2015年3月,城市建设中公共自行车项目攻城略地发展迅猛,但在各城市中效果喜忧参半。对其中公共自行车居民需求分析有助于找准其市场定位,将好事办好,使公共自行车可持续性发展下去。本文以安徽芜湖（国家首批城市建设试点）为例,通过问卷调查和数据分析,进行城市公共自行车市场细分、目标市场选择和市场定位的实证分析,来了解公共自行车的市场需求,为相关的决策和研究提供一定的参考依据。  相似文献   

The validity and reliability of a sample of 10 Wattbike cycle ergometers     

Barney Wainwright  Carlton Brian Cooke  John Paul O’Hara 《Journal of sports sciences》2017,35(14):1451-1458

ABSTRACT

The purpose of the study was to assess the validity and inter-bike reliability of 10 Wattbike cycle ergometers, and to assess the test–retest reliability of one Wattbike. Power outputs from 100 to 1000 W were applied using a motorised calibration rig (LODE) at cadences of 70, 90, 110 and 130 rev · min^?1, which created nineteen different intensities for comparison. Significant relationships (P < 0.01, r² = 0.99) were found between each of the Wattbikes and the LODE. Each Wattbike was found to be valid and reliable and had good inter-bike agreement. Within-bike mean differences ranged from 0.0 W to 8.1 W at 300 W and 3.3 W to 19.3 W at 600 W. When taking into account the manufacturers stated measurement error for the LODE (2%), the mean differences were less than 2%. Comparisons between Wattbikes at each of the nineteen intensities gave differences from 0.6 to 25.5 W at intensities of 152 W and 983 W, respectively. There was no significant difference (P > 0.05) between the measures of power recorded in the test–retest condition. The data suggest that the Wattbike is an accurate and reliable tool for training and performance assessments, with data between Wattbikes being able to be used interchangeably.  相似文献   

Development of a grinding-specific performance test set-up     

C. G. Olesen  B. H. Larsen  E. L. Andresen  M. de Zee 《European Journal of Sport Science》2015,15(3):242-247

Abstract

The aim of this study was to develop a performance test set-up for America's Cup grinders. The test set-up had to mimic the on-boat grinding activity and be capable of collecting data for analysis and evaluation of grinding performance. This study included a literature-based analysis of grinding demands and a test protocol developed to accommodate the necessary physiological loads. This study resulted in a test protocol consisting of 10 intervals of 20 revolutions each interspersed with active resting periods of 50 s. The 20 revolutions are a combination of both forward and backward grinding and an exponentially rising resistance. A custom-made grinding ergometer was developed with computer-controlled resistance and capable of collecting data during the test. The data collected can be used to find measures of grinding performance such as peak power, time to complete and the decline in repeated grinding performance.  相似文献   

模拟高原环境下自行车驴友急性骑行能力研究*     

蓝道忠  翁锡全  胡婧  周柏星  黄丽英 《广州体育学院学报》2015,35(3):86-89

目的:探讨模拟高原环境下急性骑行对自行车驴友运动能力的影响。方法:受试对象为7名华南农业大学一年级男性学生,平均年龄19.80±0.83岁,为自行车驴友,没有高原旅行经历。受试者分别在常氧环境和模拟常压低氧环境(氧含量16.8%)进行踏功率自行车运动,强度从50W(50rpm)开始,每3min递增50W至250W,然后要求受试者以最大能力运动至力竭,测试指标包括运动前、每级负荷后即刻和运动后心率、RPE、血乳酸及力竭时间。结果:两种环境下的心率与RPE均随着运动强度的增大而呈上升趋势,在模拟高原环境下从150W至250W以及力竭后心率上升幅度高于常氧,而RPE从150W后至运动结束时也高于常氧环境,但均无统计学差异(P>0.05),并且力竭时间非常显著性缩短(P<0.01)。结论:高原环境下自行车驴友骑行能力有一定下降,提示自行车驴友初入高原时要适当降低骑行强度及作适当的休息。  相似文献   

小轮车竞速运动的特点及发展对策     

庞建超 《军事体育进修学院学报》2012,31(2):73-74,86

简要分析小轮车竞速项目的特点和技术要求,介绍了小轮车运动的发展历史和现状,并针对我国小轮车运动发展晚等现实,从普及该项运动路径、改进训练方法、提升实战能力和壮大人才队伍等方面提出指导性发展对策。  相似文献   

电动自行车后轮碟刹安装设计     

章文英  李银海  王瑞敏 《金华职业技术学院学报》2009,9(3):34-36

随着电动自行车设计的最高车速的提高，对刹车系统提出更高的要求，为此提出电动车实现后轮碟刹的设想。经对后轮碟刹实现的可能性及后轮碟刹装置安装方法的分析，结果：后轮具有安装碟刹装置的空间。并可以通过改造链条齿轮或电机壳的方法来实现后轮碟刹装置的安装。  相似文献   

城市自行车交通现状及对策浅议     

招晓菊  詹柏斌 《深圳信息职业技术学院学报》2014,(1):67-71,76

针对当前城市自行车交通发展中存在的一些问题,从城市交通可持续发展和绿色交通优先发展的角度出发,探讨了自行车交通的发展前景、存在的主要问题、自行车交通的发展对策等内容,以促进城市自行车交通的健康发展.  相似文献