Comparison of kinematics in skilled and unskilled arms of the same recreational baseball players     

S. Gray  S. Watts  D. Debicki 《Journal of sports sciences》2013,31(11):1183-1194

Abstract

We examined mechanisms of coordination that enable skilled recreational baseball players to make fast overarm throws with their skilled arm and which are absent or rudimentary in their unskilled arm. Arm segment angular kinematics in three dimensions at 1000 Hz were recorded with the search-coil technique from the arms of eight individuals who on one occasion threw with their skilled right arm and on another with their unskilled left arm. Compared with their unskilled arm, the skilled arm had: a larger angular deceleration of the upper arm in space in the forward horizontal direction; a larger shoulder internal rotation velocity at ball release (unskilled arms had a negative velocity); a period of elbow extension deceleration before ball release; and an increase in wrist velocity with an increase in ball speed. It is suggested that some of these differences in arm kinematics occur because of differences between the skilled and unskilled arms in their ability to control interaction torques (the passive torque at one joint due to motion at adjacent joints). It is proposed that one reason unskilled individuals cannot throw fast is that, unlike their skilled counterparts, they have not developed the coordination mechanisms to effectively exploit interaction torques.  相似文献   

Physiological variables and performance markers of serving soldiers from two “elite” units of the British Army     

Richard J. Simpson  Susan C. Gray 《Journal of sports sciences》2013,31(6):597-604

Abstract

The aim of this study was to compare selected physiological variables and performance markers of soldiers from two “elite” units of the British Army. Ten soldiers from each of the two units were recruited for this study (n = 20). All participants completed three tests while carrying a 20 kg backpack load: (1) a maximal treadmill test using the Bruce protocol; (2) a 2 mile backpack run test specific to Unit A on a consistently flat tarmac road; and (3) a 29 km time-trial over hilly terrain typical of a mountainous area used by Unit B for performance assessment. Heart rate, maximal blood lactate concentration and performance (run time) were assessed during all three tests, with peak oxygen uptake also being measured during the maximal treadmill test. Measurements of anthropometry, isokinetic strength and mental toughness (MT48) were also recorded. There were no significant differences in terms of performance markers between the units (P > 0.05). Performance on the maximal treadmill test correlated with performance on the 2 mile backpack run test (r = ?0.57) and 29 km time-trial (r = ?0.66). Performance on the 2 mile backpack run test in turn correlated with 29 km time-trial performance (r = ?0.77), accounting for 59% of the variance. In conclusion, the maximal treadmill test and the 2 mile backpack run test are useful indicators of performance on the arduous hill march and could be employed in the screening and selection of potential recruits.  相似文献   

The Effect of Climbing Wall Use on the Grip Strength of Fourth-Grade Students     

Cathy D. Lirgg  Ro Dibrezzo  Michelle Gray  Travis Esslinger 《Research quarterly for exercise and sport》2013,84(2):350-354

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Responses to Forces Influencing Cohesion As a Function of Player Status and Level of Male Varsity Basketball Competition     

Joseph J. Gruber  Gary R. Gray 《Research quarterly for exercise and sport》2013,84(1):27-36

Abstract

This exploratory study determined if the responses of male varsity basketball players to six factors influencing cohesion were a function of level of competitive intensity and/or the importance of the players to their team. Players on intact teams from five levels of competition – elementary school, junior high school, senior high school, small college and large college–responded to a cohesion questionnaire at the end of the season. Coaches designated five players with the most game playing time as “starters” and five players with the least game playing time as “reserves.” A team factor score for Team Performance Satisfaction, Self Performance Satisfaction, Task Cohesion, Affiliation Cohesion, Desire for Recognition and Value of Membership was calculated. Each team factor score served as the dependent variable in a 2 (player status) × 5 (level of competition) analysis ofcovariance design, with teams nested in the second factor. The won-loss record served as the covariate. Results indicated that “starters” were more satisfied with their own performance, were more task conscious, had a greater affiliation desire, and valued their membership on the team to a greater degree than the “reserves.” The elementary and junior high school team members were significantly more satisfied with the team's performance, were more satisfied with their own self performance, were more affiliation conscious, and valued their team membership to a greater degree than did college team members. The interaction between player status and level of competition was not significant for any of the factor scores.  相似文献   

Support Base Use in Two Dance Idioms     

Margaret Gray  Margaret Head Skrinar 《Research quarterly for exercise and sport》2013,84(2):184-187

Abstract

Recovery pulse rates following a 3-min. step test were obtained from 686 junior high school and 1,332 high school age subjects who were students in 55 different secondary schools throughout the six districts of the AAHPER. The pulse rates were converted to cardiovasular efficiency scores and from these, national standards were established for the 9–14 age group and for the 15 19 age group. The standards consisted of six categories from excellent to very poor. In addition, it was found that junior high school subjects scored better than high school subjects; that neither temperature nor time of day of testing had a significant effect on test scores; and that at the high school level the senior high school subjects in the Central district achieved the best scores of the six districts while at the junior high level the Central and Southern districts ranked together as best.  相似文献   

School learning resources     

Phyllis Joseph  Bob Gray 《TechTrends》1991,36(6):33-34

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Evidence-based policy-making and exam board insider researchers: creating communicative spaces     

Lena Gray 《Assessment in Education: Principles, Policy & Practice》2020,27(2):142-159

ABSTRACT

This article conceptualises the relationship between exam board insider research and the policy-making context in which they operate. Exam board researchers are constrained by commercial and political interests in disclosing their knowledge. and face pressures in disseminating research, butalso find themselves working in contexts where calls to ‘evidence-based policy-making’ are ubiquitous. This can deprofessionalise and disenfranchise the researcher.. This article will depict the context faced by exam board researchers attempting to influence policy before portraying possible responses, evaluating how these can be applied to exam board research, with reference to research on standard-setting. The article will build on a conceptualisation of successful exam board insider research as the creation of Habermasian ‘communicative spaces’, applying lessons from research–policy interface literature to that conceptualisation. Inapplying those lessons, the article will suggest possible solutions to the problems faced by that group in their attempts to influence policymakers.  相似文献   

The professional learning needs and priorities of higher-education-based teacher educators in England,Ireland and Scotland     

Gerry Czerniawski  Donald Gray  Ann MacPhail  Yvonne Bain  Paul Conway  Ainat Guberman 《师资教育杂志》2018,44(2):133-148

Against a rapidly changing policy landscape for teacher education, exacerbated by ‘Brexit’ in the UK, findings are presented from an electronic survey of 272 higher-education based teacher educators in England, the Republic of Ireland and Scotland about their experiences of, and priorities for, professional learning. While the data generated were mainly quantitative data, qualitative features were embedded within the survey design. Both types of data have been used to draw out complexities that emerge when exploring a professional group of educators responsible for the preparation of a future generation of teachers. The findings are presented and discussed in relation to the professional demographics of the sample, research expectations placed on them and teacher educators’ priorities for professional learning. Given the unique occupational position of teacher educators, their importance in the quality of teacher education and the lack of formal focus on their professional development, our starting point for teacher educators’ professional development lies in their practice situated and positioned within global, regional, national and local policy contexts.  相似文献   

Meaningful interaction: toward a new theoretical approach to online instruction     

Robert Gray 《Technology, Pedagogy and Education》2019,28(4):473-484

ABSTRACT

Taking full advantage of the educative benefits of interaction in digital learning environments will require the development of new theoretical frameworks that can contribute to a richer understanding of interaction. Literary theory provides an excellent place to develop such a framework and advanced understanding. Literary theory enables us to reconceptualise online courses as ‘texts’, thereby equipping us with more sophisticated modes of analysis for the teaching and learning process. By rethinking online courses as texts, and better yet as what Roland Barthes has described as ‘writerly’ texts, we can improve interaction in the online classroom. More importantly, we can move toward a more meaningful form of interaction, where learners interact with course content at the level of meaning and meaning making, where interaction becomes a full participation in the production of a lesson’s meaning. Indeed, this aim of co-producing meaning should be the primary objective of all learning.  相似文献   

The early training project: a seventh-year report   总被引：2，自引：0，他引：2  

S W Gray  R A Klaus 《Child development》1970,41(4):909-924

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