The relationship between inertial measurement unit-derived ‘force signatures’ and ground reaction forces during cricket pace bowling     

Samuel J. Callaghan  Robert G. Lockie  Warren A. Andrews  Robert F. Chipchase  Sophia Nimphius 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(3):307-321

Abstract

This study assessed the reliability and validity of segment measured accelerations in comparison to front foot contact (FFC) ground reaction force (GRF) during the delivery stride for cricket pace bowlers. Eleven recreational bowlers completed a 30-delivery bowling spell. Trunk- and tibia-mounted inertial measurement units (IMUs) were used to measure accelerations, converted to force, for comparisons to force plate GRF discrete measures. These measures included peak force, impulse and the continuous force–time curve in the vertical and braking (horizontal) planes. Reliability and validity was determined by intra-class correlation coefficients (ICC), coefficient of variation (CV), Bland–Altman plots, paired sample t-tests, Pearson’s correlation and one-dimensional (1D) statistical parametrical mapping (SPM). All ICC (0.90–0.98) and CV (4.23–7.41%) were acceptable, except for tibia-mounted IMU braking peak force (CV = 12.44%) and impulse (CV = 18.17%) and trunk vertical impulse (CV = 17.93%). Bland–Altman plots revealed wide limits of agreement between discrete IMU force signatures and force plate GRF. The 1D SPM outlined numerous significant (p < 0.01) differences between trunk- and tibia-located IMU-derived measures and force plate GRF traces in vertical and braking (horizontal) planes. The trunk- and tibia-mounted IMUs appeared to not represent the GRF experienced during pace bowling FFC when compared to a gold-standard force plate.  相似文献   

汽车变速器CAE仿真与试验分析     

赖俊  梅自元 《清远职业技术学院学报》2020,(1):51-54

变速器作为汽车动力总成系统的关键部件,其功能的可靠、耐久的长短等性能直接影响到汽车的整体功能。CAE仿真与试验是变速箱性能验证的重要手段,通过结合设计阶段的CAE仿真与样件阶段的试验验证进行对比研究,能够使变速器在量产前完善设计,减少试验的样本量,从而实现缩短变速器设计周期和降低成本的目的。  相似文献   

Reference power values for the jump squat exercise in elite athletes: A multicenter study     

Pedro L. Valenzuela  Michael McGuigan  Guillermo Sánchez-Martínez  Elaia Torrontegi  Javier Vázquez-Carrión  Zigor Montalvo 《Journal of sports sciences》2020,38(19):2273-2278

ABSTRACT

The present study aimed to provide reference values for lower-limb muscle power assessed during the incremental jump squat (JS) test in elite athletes (i.e., professional athletes competing at international level). We pooled data from all JS tests performed by elite athletes of different sports in two high-performance centres between 2015 and 2019, and computed reference values (i.e., terciles) for mean power (MP), mean propulsive power (MPP), and peak power (PP). Reference values were obtained from 684 elite athletes (458 male and 226 female) of 16 different sports (boxing, judo, karate, fencing, taekwondo, wrestling, basketball, soccer, futsal, handball, rugby union, badminton, tennis, long distance running, triathlon, and sprinting). Significant differences (p < 0.001) were found between male and female athletes for MP (7.47 ± 1.93 and 6.15 ± 1.68 W·Kg^?1, respectively), MPP (10.50 ± 2.75 and 8.63 ± 2.43 W·Kg^?1), and PP (23.64 ± 6.12 and 19.35 ± 5.49 W·Kg^?1). However, the velocity at which these power measures was attained seemed to be independent of sex (~0.95, 1.00 and 2.00 m·s^?1 for mean, mean propulsive, and peak velocity, respectively) and homogeneous across different sport disciplines (coefficient of variation <10%). These data can be used to classify athletes’ power capabilities, and the optimum velocity ranges provided here could be useful for training purposes.  相似文献   

可用性测试方法在IA研究中的应用   总被引：9，自引：1，他引：9  

甘利人  王晓蓉 《情报理论与实践》2004,27(4):415-417,443

企业进行信息构建时必须研究用户，而可用性测试作为信息构建的重要组成部分，是一种研究用户的有效手段，通过规范的可用性测试过程，可了解用户行为并指导网站设计。作为可用性测试方法的一种，卡片分拣法可以探索用户对于网站信息如何分类，以此提高用户搜索成功率。  相似文献   

大型应用软件白盒测试的组织与管理模式研究     

彭浩  贾国柱 《中国科技信息》2007,(4):113-116,119

针对国内软件企业在软件测试的管理方面存在的问题，结合一个实际的第三方大型软件白盒测试项目，从项目管理的角度提出了一套针对大型应用软件的白盒测试的组织和管理模式，为软件测试管理的规范化提供参考。  相似文献   

机载无线电设备检测系统硬件设计方案     

隋秀玉 《中国科技信息》2006,(5):84-84,87

为了保障机载无线电设备的正常工作，完成对机载无线电设备进行定期检测和维修，我们提出了机载无线电设备测试系统的一种优化设计，配合软件系统以后，使大部分信号分析比较，以及对输入信号，电源控制等方面充分实现智能化，本文主要介绍了用Protel99来实现此机载无线电设备综合检测系统的硬件设计方案以及基本设计框图。  相似文献   

运化三元能量程度不同者的智力比较研究     

王极盛  赫尔实  刘玉珠 《人天科学研究》1996,(6)

为了探索元极学在实际中的应用,采用智力测验方法,对学习元极学的深浅程度不同者进行了测试和研究,结果表明,学习元极学对开发智力的某些方面如记忆、动作协调、注意分配等有一定作用,学习的程度越深,对智力的开发越大。  相似文献   

What Do We Really Know About the edTPA? Research,PACT, and Packaging a Local Teacher Performance Assessment for National Use     

Cristyne Hébert 《The Educational forum》2017,81(1):68-82

This article calls attention to the overreliance on research about the Performance Assessment for California Teachers (PACT)—often labeled edTPA's predecessor—as justification for the edTPA. The article argues that the distinctions between the assessments are too vast to rely on PACT data to support the edTPA, given the localized nature of PACT and the way in which it is scored.  相似文献   

The emergence of the quantified child     

Rebecca Smith 《Discourse: Studies in the Cultural Politics of Education》2017,38(5):701-712

Using document analysis, this paper examines the historical emergence of the quantified child, revealing how the collection and use of data has become normalized through legitimizing discourses. First, following in the traditions of Foucault's genealogy and studies examining the sociology of numbers, this paper traces the evolution of data collection in a range of significant education policy documents. Second, a word count analysis was used to further substantiate the claim that data collection and use has been increasingly normalized through legitimizing discourses and routine actions in educational settings. These analyses provide evidence that the need to quantify educational practices has been justified over long periods of time through a variety of documents and that the extent to which data governs educators’ thoughts, discourses, and actions has dramatically increased during the past century.  相似文献   

Introductory statistics in the garden          下载免费PDF全文

John C. Wagaman 《Teaching Statistics》2017,39(2):52-56

This article describes four semesters of introductory statistics courses that incorporate service learning and gardening into the curriculum with applications of the binomial distribution, least squares regression and hypothesis testing. The activities span multiple semesters and are iterative in nature.  相似文献