Relative shank to thigh length is associated with different mechanisms of power production during elite male ergometer rowing

The effect of anthropometric differences in shank to thigh length ratio upon timing and magnitude of joint power production during the drive phase of the rowing stroke was investigated in 14 elite male rowers. Rowers were tested on the RowPerfect ergometer which was instrumented at the handle and foot stretcher to measure force generation, and a nine segment inverse dynamics model used to calculate the rower's joint and overall power production. Rowers were divided into two groups according to relative shank thigh ratio. Time to half lumbar power generation was significantly earlier in shorter shank rowers (p = 0.028) compared to longer shank rowers, who showed no lumbar power generation during the same period of the drive phase. Rowers with a relatively shorter shank demonstrated earlier lumbar power generation during the drive phase resulting from restricted rotation of the pelvic segment requiring increased lumbar extension in these rowers. Earlier lumbar power generation and extension did not appear to directly affect performance measures of the short shank group, and so can be attributed to a technical adaptation developed to maximise rowing performance.     

Throwing and catching movements exhibit post-activation potentiation effects following fatigue

Many sport and exercise activities require powerful movements of the upper body. Despite their importance, there is a paucity of research examining stretch-shortening cycle (SSC) activities occurring in the upper limbs. The purpose of this study was to examine the effect of fatigue on throwing performance (height of throw) and biomechanical factors of the upper limbs (reactive strength index; hand contact time) using a specially constructed sledge apparatus for the upper body. Ten male subjects aged between 19 and 21 years performed a series of rebound throws (RBT) in a non-fatigued state to obtain a maximal baseline throw score. Subjects then performed a RBT fatiguing protocol on the upper body sledge followed by further RBT, at 15, 45, 120 and 300-seconds post fatigue. Markers on the subjects' limb and the sledge were analysed using Motion Analysis Corporation 3-D kinematic analysis system (200 Hz). Throwing height, contact time and reactive strength index were determined. Mean throwing height and reactive strength index showed significant decreases following fatigue and increases during recovery (p < 0.05). The results confirm the presence of post-activation potentiation (PAP) in RBT performance. This finding could be useful when optimising recovery periods in training or implementing complex training methods.     

Effect of Hand Spacing and Rear Knee Angle on the Sprinter's Start

Abstract

Twelve male subjects with no specialized training in sprint running were used to study effects upon the sprinter's start when hand spacing and rear knee angle were systematically altered. Results indicated that hand spacing had an effect on the start during the first 10 yd. of the sprint. The effect of rear knee angle was present at 10 yd. and the advantage gained at 10 yd. was still present at 30 yd.     

Effects of Two Instructional Approaches on Skill Development,Knowledge, and Game Performance

Two instructional approaches that have been of interest in promoting sport have been the Sport Education Model (SEM) and the Traditional Style (TS) of teaching physical education. The purpose of this study was to investigate how SEM and TS would affect skill development, knowledge, and game performance for volleyball at the secondary level. A 2 × 3 (group × time) research design was utilized on 47 secondary students testing volleyball skills, knowledge, and game performance. Participants were placed in either the SEM or the TS via stratified randomization, and then were tested pre, mid, and post intervention through the 20-lesson volleyball unit. The 2 × 3 repeated measures Analysis of Variances (ANOVAs) with Bonferroni correction revealed no significant difference between models for skills and knowledge, but there was for game performance for group [F(1, 45) = 10.27, p < .008, η² = .19], time [F(2, 90) = 8.62, p < .008, η² = .16], and group × time interaction [F(2, 90) = 8.43, p < .008, η² = .16]. If the goal of the physical education program is to promote quality game play, the SEM may be more effective than the TS.     

Sport and Racial Discrimination in Colonial Zimbabwe: A Reanalysis

The British colony of Southern Rhodesia, later governed by a white settler minority as unilaterally-independent Rhodesia, practiced racial segregation in many spheres, including education, health care access and political participation. Though racial segregation tended to exist on a less formal level than in Rhodesia's neighbour, apartheid South Africa, segregationist policies were nonetheless invasive and virtually complete in some areas. Sport was a heavily contested sphere, in which pockets of black African autonomy and advancement existed alongside near-complete white domination, largely, but not entirely, free of government intrusion. This article is an effort to develop a working hypothesis of racial discrimination in Rhodesian sport, discrimination that was never as formal or complete as in South Africa but which nonetheless provided a firm foundation for Rhodesia's exclusion from international sporting competition in the 1970s.     

“冰球”在哪里:高级体育媒体学术的十大主题

从消费、碎片化、变迁三个关键词入手,提出了未来美国体育与传播研究的十个主题,即消费分层背景下的体育与体育节目、体育赛事之外的主要消费、多视角的体育事件中的身份研究、关注传播效果研究、对媒介"妖魔化"的再思考、保持体育媒介研究身份前提下的多学科研究、学术研究成果的传播、决定什么是新方向、时间对消费行为的影响和关注被忽视的领域。报告认为从不同社会阶层的角度分析体育节目的观看行为、体育消费行为和媒介体育的传播效果是最重要的研究领域,体育事件中的性别身份研究、球迷身份研究、种族、民族和国家主义等多学科的交叉研究以及新技术、新媒介出现对体育新闻与传播的影响也将继续是美国体育新闻与传播研究的方向。     

Conceptualizing climate change in the context of a climate system: implications for climate and environmental education

Today there is much interest in teaching secondary students about climate change. Much of this effort has focused directly on students’ understanding of climate change. We hypothesize, however, that in order for students to understand climate change they must first understand climate as a system and how changes to this system due to both natural and human influences result in climatic and environmental changes and feedbacks. The purpose of this article is to articulate a climate system framework for teaching about climate change and to stimulate discussion about what secondary students should know and understand about a climate system. We first provide an overview of the research on secondary students’ conceptions of climate and climate change. We then present a climate system framework for teaching about climate and climate change that builds on students’ conceptions and scientific perspectives. We conclude by articulating a draft conceptual progression based on students’ conceptions and our climate system framework as a means to inform curriculum development, instructional design, and future research in climate and environmental education.     

Fan culture and motivation in the context of successful women’s professional team sports: a mixed-methods case study of Portland Thorns fandom

Abstract

By the metric of average home attendance, the Portland Thorns of the National Women’s Soccer League are the most popular women’s professional sports team in the world. This paper investigates that distinct sports context through a mixed-methods case study of Thorns fandom, asking what fans themselves perceive to be salient elements of a successful fan culture for women’s professional soccer and what motivates their fandom. Drawing on survey data that are contextualized by ethnographic observations and interviews, we offer an interpretive analysis of ways Thorns fandom hybridizes elements of traditional and alternative sports fandom. Our findings highlight the emphasis Thorns fans put on quality soccer in a professional atmosphere where fans themselves create the supporters culture, along with the symbolic importance to fans of identifying with values such as gender empowerment, diversity and inclusion. We discuss ways these themes might offer and inform alternative models of sports fandom.     

A cross‐sectional study of prosodic sensitivity and reading difficulties

In this cross‐sectional study, we explore the relationship between prosodic sensitivity (suprasegmental phonology) and phonological awareness (segmental phonology) and investigate whether a group of poor readers display significant suprasegmental phonological deficits in comparison to chronological age‐matched controls and younger, reading age‐matched controls. Phonological awareness assessments were administered along with a battery of prosodic sensitivity assessments drawn from recent literature. The results showed that poor readers were outperformed by their chronological age‐matched counterparts on all measures of prosodic sensitivity. A significant main effect of group was found on the revised stress mispronunciations task and the stress assignment task from the prosodic assessment battery, the former of which remained even after controlling for individual differences in receptive vocabulary and measures of phonological awareness. Significant relationships were also found between measures of prosodic sensitivity and phonological awareness (especially phoneme awareness). These findings emphasise the importance of both segmental and suprasegmental phonological skills in children's reading development.