The biomechanical characteristics of high-performance endurance running     

Stephen J. Preece  Christopher Bramah  Duncan Mason 《European Journal of Sport Science》2019,19(6):784-792

The biomechanical profile of high-level endurance runners may represent a useful model that could be used for developing training programmes designed to improve running style. This study, therefore, sought to compare the biomechanical characteristics of high-performance and recreational runners. Kinematic and kinetic measurements were taken during overground running from a cohort of 14 high-performance (8 male) and 14 recreational (8 male) runners, at four speeds ranging from 3.3 to 5.6?m?s^?1. Two-way ANOVA analysis was then used to explore group and speed effects and principal component analysis used to explore the interdependence of the tested variables. The data showed the high-performance runners to have a gait style characterised by an increased vertical velocity of the centre of mass and a flight time that was 11% longer than the recreational group. The high-performance group were also observed to adopt a forefoot strike pattern, to contact the ground with their foot closer to their body and to have a larger ankle moment. Importantly, although observed group differences were mostly independent of speed, the tested variables showed a high degree of interdependence suggesting an underlying unitary phenomenon. This is the first study to compare high-performance and recreational runners across a full range of kinematic and kinetic variables. The results suggest that high-performance runners maintain stride length with a prolonged aerial phase, rather than by landing with a more extended knee. These findings motivate future intervention studies that should investigate whether recreational runners could benefit from instruction to decrease shank inclination at foot contact.  相似文献   

Validity and reliability of a low-cost dynamometer to assess maximal isometric strength of upper limb     

Natalia Romero-Franco  Juan C Fernández-Domínguez  Juan A Montaño-Munuera  Javier Romero-Franco  Pedro Jiménez-Reyes 《Journal of sports sciences》2019,37(15):1787-1793

Muscle imbalance and deficit are key parameters for guiding rehabilitation and sports sessions and avoiding injuries. However, the high cost and non-portable nature of most instruments employed for muscle strength assessment frequently hamper an affordable evaluation in field conditions. This study evaluated the validity and reliability of a low-cost digital dynamometer to assess the maximal isometric strength of upper limb muscles. Fourteen physically active volunteers performed the main movements of the upper limb at maximal isometric strength: flexion-extension, internal-external rotation and abduction-adduction of the shoulder; and flexion-extension of both elbow and wrist. Validity was examined by comparing the strength values from the low-cost digital dynamometer and those measured by an isokinetic dynamometer, assumed as the gold standard. The correlation between both devices was perfect (r > 0.913), while Bland-Altman plots showed absolute agreement between both devices, the maximum range of the values of bias was ?0.99–1.00 N in wrist extension. Inter-tester and intra-tester reliability were excellent for all movements (ICC ≥ 0.855). The low-cost digital dynamometer showed strong validity and excellent reliability in assessing maximal isometric strength during the main movements of the upper limb. Professionals may use it for an affordable isometric muscle strength assessment in field situations.  相似文献   

基于单向流固耦合的不同风速下帆板帆翼空气动力性能仿真     

雷晓珊  马勇  蔺世杰 《武汉体育学院学报》2019,53(11):95-100

目的：探究不同风速对帆板帆翼结构以及周围流场的影响。方法：以奥运女子级别的Neil Pryde RS：X帆板帆翼为研究对象,考虑空气动力与结构的流固耦合效应,利用ANSYS Workbench进行单向流固耦合分析。结果：Realizable模型适合计算帆翼周围的流场湍流度,在风速为2m/s时帆翼升阻比最大;随着风速的增大,帆翼面发生变形和振动会导致风激振现象、背风面产生明显的涡脱现象,且帆翼表面应力区增大,全帆的应变逐步增加。结论：不同风速下的帆翼迎风面和背风面的压力分布、帆翼整体空气动力有一定差异,运动员比赛中应该根据当时风况调整帆翼参数。  相似文献   

不同步行和跑步速度对后足角度和足偏角的影响          下载免费PDF全文

赵滢  陆阿明 《体育科研》2017,(6):93-100

通过进行zebris步态测试和后足角度拍摄,采集和分析速度变化对步行和跑步时后足角度和足偏角的影响,从而科学指导广大健身爱好者进行合理的步行和跑步运动,预防运动损伤。实验结果显示：（1）相较于自身步行偏好速度,采用实验步行设定速度时左右足后足角度均显著增大,左右足足偏角均显著减小（1.33 m/s例外）;（2）实验步行设定速度之间,相较于1.33 m/s速度步行,以1.56 m/s和1.78 m/s步行时左足后足角度显著增大,以1.56 m/s步行时右足足偏角显著减小;（3）相较于自身跑步偏好速度,当以慢于自身跑步偏好速度跑步时,左右足后足角度和足偏角均无显著性差异,而当以快于自身跑步偏好速度跑步时,左右足的足偏角显著减小,后足角度无显著性差异;（4）快于自身跑步偏好速度时比慢于自身跑步速度时左右足的足偏角显著减小（以3.61 m/s跑步时比1.78 m/s跑步时左足后足角度增大）;（5）快于自身跑步偏好速度时,以3.61 m/s跑步时比2.78 m/s跑步时左右足足偏角显著减小。实验结果表明：（1）相较于其他实验设定速度,以自身偏好速度步行时,后足角度较小,足偏角较大,可以有效预防运动损伤;（2）从后足角度和足偏角考虑,当步行速度较快时,保持步长,适当减小足偏角可以减少踝关节损伤。  相似文献   

腰痛羽毛球运动员的功能评估          下载免费PDF全文

李男  檀志宗  叶晶龙  刘新宇  任雪 《体育科研》2017,(6):82-86

研究目的：对腰痛羽毛球运动员的部分功能进行测试,观察其活动范围、肌肉力量、肌电活动以及相应对称性。为了解羽毛球运动员损伤机制发生提供科学依据。研究对象：6名腰痛羽毛球运动员（男运动员4名,女运动员2名）。研究方法：对研究对象分别进行日本矫正外科协会（JOA）评分量表、躯干旋转、胸椎旋转、髋关节内外旋活动度、躯干等速旋转力量、等长背伸活动的肌电活动测试,并观察两侧差异比的平均值。研究结果：（1）腰痛运动员的躯干旋转、胸椎旋转以及髋关节外旋活动度平均差异比为（31.98±21.53）%,（19.8±17.08）%,（13.81±4.43）%大于10%,仅髋关节内旋活动度平均差异比为（5.62±5.63）%小于10%。胸椎和髋关节旋转动度有减小的趋势;（2）等速躯干旋转两侧峰力矩和平均功率差异没有显著性意义,峰力矩平均差异比为（5.45±1.78）%小于10%,而平均功率平均差异比为（12.78±11.40）%大于10%;（3）在等长背伸活动中,竖脊肌肌电活动的平均两侧差异比为（14.18±9.84）%大于10%,而多裂肌肌电活动的平均两侧差异比（9.90±7.92）%接近10%;竖脊肌和多裂肌的中位频率斜率（Median Frequency slope,MFs）均出现下降的趋势,但两侧差异比为（4.68±3.17）%,（5.35±5.40）%小于10%。结论：（1）腰痛羽毛球运动员躯干旋转、胸椎旋转、髋关节外旋活动范围存在对称性问题,且胸椎旋转、髋关节旋转有减少趋势;（2）躯干等速旋转平均功率存在对称性问题;（3）等长背伸任务中,竖脊肌和多裂肌出现疲劳,肌电活动存在对称性问题。  相似文献   

Optimal sampling frequency in recording of resistance training exercises     

Paolo Bardella  Irene Carrasquilla García  Marco Pozzo  Julio Tous-Fajardo  Eduardo Saez de Villareal 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):102-114

The purpose of this study was to analyse the raw lifting speed collected during four different resistance training exercises to assess the optimal sampling frequency. Eight physically active participants performed sets of Squat Jumps, Countermovement Jumps, Squats and Bench Presses at a maximal lifting speed. A linear encoder was used to measure the instantaneous speed at a 200 Hz sampling rate. Subsequently, the power spectrum of the signal was computed by evaluating its Discrete Fourier Transform. The sampling frequency needed to reconstruct the signals with an error of less than 0.1% was f_99.9 = 11.615 ± 2.680 Hz for the exercise exhibiting the largest bandwidth, with the absolute highest individual value being 17.467 Hz. There was no difference between sets in any of the exercises. Using the closest integer sampling frequency value (25 Hz) yielded a reconstruction of the signal up to 99.975 ± 0.025% of its total in the worst case. In conclusion, a sampling rate of 25 Hz or above is more than adequate to record raw speed data and compute power during resistance training exercises, even under the most extreme circumstances during explosive exercises. Higher sampling frequencies provide no increase in the recording precision and may instead have adverse effects on the overall data quality.  相似文献   

短道速滑运动员选材要素分析     

马健 《冰雪运动》2008,30(2):7-10

通过查阅相关文献的方法,结合短道速滑项目实际情况,讨论短道速滑运动员选材的相关问题及意义,认为体能、心理、智力等因素是短道速滑运动员选材中的核心要素,把体能、心理、智力等指标因素与短道速滑运动相结合并加以分析,从实践的角度对其内容进行了筛选与界定,为教练员在进行短道速滑运动员科学选才时,提供一定的参考。  相似文献   

垂直初速度对提高跳远成绩的影响   总被引：2，自引：0，他引：2  

王伟光 《广州体育学院学报》1999,(3)

依据中外优秀跳远选手的比赛数据统计和对比分析,运用运动生物力学原理和方法,论述了垂直初速度对跳远成绩的影响及其意义,揭示了一次成功跳远所应具备的主要技术指标。  相似文献   

我国速滑冬奥会选手改进有氧训练的个性化研究——第20届冬奥会速滑科研攻关思考之一   总被引：1，自引：1，他引：0  

严力  赵滨杰  米博  李欣 《冰雪运动》2008,30(1):1-6

研究目的：针对冬季奥运会速度滑冰500m项目比赛规程变化的新情况,为提高我国奥运选手有氧代谢能力与血乳酸清除的效率,以适应比赛规则的变化,探索适合优秀速滑短距离选手个人特点的有氧训练新途径。研究方法：采用血乳酸控制训练负荷的方法,对2名参加冬奥会选手改进后的有氧训练过程进行实时监控,并通过不同赛季的比较对有氧训练改进的效果进行判定。研究结果：有氧训练改进后,2005～2006赛季与2004～2005赛季相比,王曼利500m成绩提高0.75s,15min血乳酸峰值浓度下降了2mmol/L,30min血乳酸峰值浓度下降了0.6mmol/L;于凤桐500m成绩提高了0.51s,15min血乳酸峰值浓度下降了1.8mmol/L,30min血乳酸峰值浓度下降了1.4mmol/L。研究结论：有氧训练的改进,提高了运动员机体血乳酸清除效率,使其能在最短时间将血乳酸降至较低水平,达到了适应冬奥会比赛日程变化的目的。  相似文献   

我国速滑运动员科学选材现状分析   总被引：2，自引：1，他引：1  

滕海坤  柏连龙 《冰雪运动》2008,30(3):1-4

为了使我国速滑运动员选材阶段的划分更加合理、指标更加科学、评价方法更加规范,采用对近年来我国速滑运动员科学选材文献资料进行收集、分析、整理和各地速滑运动员选材情况进行调查的方法,发现我国速滑运动员科学选材工作现状处于缺乏科学系统性的停滞状态,速滑选材仍以经验选材为主;提出速滑运动员的选材应以生物年龄划分为4个阶段,且应在充分考虑遗传因素的前提下,对各阶段进行不同的身体形态、身体机能、身体素质、心理因素和专项成绩等方面的测试,并参考教练员对运动员的评价;建议尽快完善我国速滑运动员科学选材机构,提高基层教练员科学选材的基本知识和技能。  相似文献