Development and validation of a method to directly measure the cable force during the hammer throw   总被引：1，自引：0，他引：1  

Brice SM  Ness KF  Rosemond D  Lyons K  Davis M 《Sports biomechanics / International Society of Biomechanics in Sports》2008,7(2):274-287

The development of cable force during hammer-throw turns is crucial to the throw distance. In this paper, we present a method that is capable of measuring cable force in real time and, as it does not interfere with technique, it is capable of providing immediate feedback to coaches and athletes during training. A strain gauge was mounted on the wires of three hammers to measure the tension in the wire and an elite male hammer thrower executed three throws with each hammer. The output from the gauges was recorded by a data logger positioned on the lower back of the thrower. The throws were captured by three high-speed video cameras and the three-dimensional position of the hammer's head was determined by digitizing the images manually. The five best throws were analysed. The force acting on the hammer's head was calculated from Newton's second law of motion and this was compared with the force measured via the strain gauge. Qualitatively the time dependence of the two forces was essentially the same, although the measured force showed more detail in the troughs of the force-time curves. Quantitatively the average difference between the measured and calculated forces over the five throws was 76 N, which corresponds to a difference of 3.8% for a cable force of 2000 N.  相似文献   

Preordained science and student autonomy: the nature of laboratory tasks in physics classrooms     

Timothy P. Olsen  Peter W. Hewson  Lyman Lyons 《International Journal of Science Education》2013,35(7):775-790

The central question facing humankind is 'What kind of society are we to have?' We argue that in order to begin to answer this question, citizens need to recognize that one of the driving forces determining our society is that science is a human social activity like any other. This flies in the face of much of the rhetoric and ideology about science - the stories and myths of formal and informal education. We wish to encourage both a socially responsible science and a public mindful of its strengths and weaknesses. We explore two case studies to illustrate our concerns. These are the construction of knowledge about Acquired Immune Deficiency Syndrome (AIDS), and the social construction of safety standards for exposure to low-level ionizing radiation. These two health-related controversial scientific issues illustrate the problematic nature of much of science and the implications for the public at large.  相似文献   

Academic performance and self-regulatory skills in elite youth soccer players     

Laura Jonker  Marije T. Elferink-Gemser  Tynke T. Toering  James Lyons  Chris Visscher 《Journal of sports sciences》2013,31(14):1605-1614

Abstract

Although elite athletes have been reported to be high academic achievers, many elite soccer players struggle with a stereotype of being low academic achievers. The purpose of this study was to compare the academic level (pre-university or pre-vocational) and self-regulatory skills (planning, self-monitoring, evaluation, reflection, effort, and self-efficacy) of elite youth soccer players aged 12–16 years (n = 128) with those of 164 age-matched controls (typical students). The results demonstrate that the elite youth soccer players are more often enrolled in the pre-university academic system, which means that they are high academic achievers, compared with the typical student. The elite players also report an increased use of self-regulatory skills, in particular self-monitoring, evaluation, reflection, and effort. In addition, control students in the pre-university system had more highly developed self-regulatory skills than those in the pre-vocational system, whereas no difference was observed within the soccer population. This suggests that the relatively stronger self-regulatory skills reported by the elite youth soccer players may be essential for performance at the highest levels of sport competition and in academia.  相似文献   

Foot strike patterns of recreational and sub-elite runners in a long-distance road race     

Peter Larson  Erin Higgins  Justin Kaminski  Tamara Decker  Janine Preble  Daniela Lyons 《Journal of sports sciences》2013,31(15):1665-1673

Abstract

Although the biomechanical properties of the various types of running foot strike (rearfoot, midfoot, and forefoot) have been studied extensively in the laboratory, only a few studies have attempted to quantify the frequency of running foot strike variants among runners in competitive road races. We classified the left and right foot strike patterns of 936 distance runners, most of whom would be considered of recreational or sub-elite ability, at the 10 km point of a half-marathon/marathon road race. We classified 88.9% of runners at the 10 km point as rearfoot strikers, 3.4% as midfoot strikers, 1.8% as forefoot strikers, and 5.9% of runners exhibited discrete foot strike asymmetry. Rearfoot striking was more common among our sample of mostly recreational distance runners than has been previously reported for samples of faster runners. We also compared foot strike patterns of 286 individual marathon runners between the 10 km and 32 km race locations and observed increased frequency of rearfoot striking at 32 km. A large percentage of runners switched from midfoot and forefoot foot strikes at 10 km to rearfoot strikes at 32 km. The frequency of discrete foot strike asymmetry declined from the 10 km to the 32 km location. Among marathon runners, we found no significant relationship between foot strike patterns and race times.  相似文献   

Movement profiles of elite women soccer players during international matches and the effect of opposition’s team ranking     

Adam Hewitt  Kevin Norton  Keith Lyons 《Journal of sports sciences》2014,32(20):1874-1880

Abstract

Movement patterns in elite men’s soccer have been reported in depth, but less research exists for women’s soccer. Aims of the study were to identify the movement profiles of elite women soccer players in international competition and examine the effect the level of opposition, based on Federation Internationale de Football Association (FIFA) rankings, had on the physical demands of the game. MinimaxX athlete tracking devices were used by 15 players during 13 international matches against opponent teams of varying ability. Total distance covered averaged 9292 ± 175 m. There was a decrease in high-intensity running (HIR) in the 60- to 75-min and 75- to 90-min periods compared to the 0- to 15-min period of 22.4% and 26.1%, respectively (P = 0.022, P = 0.004) although sprint distances remained unchanged across game periods. HIR distances covered were significantly greater for midfielders versus defenders, while defenders had lower sprinting compared to both midfielders and attackers. Stronger opponents elicited less HIR and greater low-speed activity (LSA) compared to playing teams of similar or lower ranking. These results are important to coaches to prepare players for international competition and show the differing demands required depending on the ability of the opponents.  相似文献   

The Impact of Human Capital and Selected Job Rewards on Community College Faculty Job Satisfaction     

Frankie W. Lyons  Duane Akroyd 《Community College Journal of Research & Practice》2014,38(2-3):194-207

Community colleges accommodate nearly half of all United States college students. Increased reliance upon community colleges is driven by the current economic downturn, rising costs of higher education, and changing expectations for today's workforce requiring advanced skill sets. Community colleges offer more affordable options for broader spectrums of students including traditional and nontraditional college students and dual-enrolled high school students.

Community college faculty facilitate student learning and program completion. A shortage of community college faculty will likely emerge as numerous faculty retire. Community college administrators need strategies for retaining and recruiting faculty amid increasing retirements. One effective strategy is to offer a work environment that cultivates positive work-related attitudes (e.g., job satisfaction). This study examines the ability of select human capital investments, intrinsic rewards, extrinsic rewards, and sociodemographics to predict overall job satisfaction for full-time community college faculty. A cross-sectional predictive design was used with secondary analysis of the 2004 National Study of Postsecondary Faculty (NSOPF:04) dataset.

Logistic Regression was utilized to determine predictive ability of the independent variables on overall job satisfaction. Results indicated that faculty were more likely to be satisfied with their work if they were satisfied with their salary, benefits and workload; were satisfied with the teaching support they received from their institutions; and if they perceived that females and minorities were treated fairly by the organization. Conversely, minority faculty were less likely to be satisfied, as were faculty who indicated they would again choose a career in academe if given the choice.  相似文献   

Nutritional, lifestyle, and weight control practices of professional jockeys   总被引：1，自引：1，他引：0  

Dolan E  O'Connor H  McGoldrick A  O'Loughlin G  Lyons D  Warrington G 《Journal of sports sciences》2011,29(8):791-799

In this study, we describe diet and lifestyle practices of professional jockeys. Participants completed a 59-item nutrition, lifestyle, and health questionnaire (n = 21) and a 7-day estimated food diary (n = 18). Acute weight loss strategies included the use of saunas (86%), exercising to induce sweating (81%), and restricted energy intake (71%). Of the smokers (38%), 56% used smoking to control weight. Most (86%) jockeys reported attaining a 2-kg weight loss for racing (if required) 24-48 h before or on the designated race-day. Mean daily energy intake (1803 ± 564 kcal) was low and appeared to provide an insufficient availability of energy for sustainment of usual daily and metabolic processes. Carbohydrate intake (3.7 ± 1.3 g · kg?1) was below recommendations for athletes. A substantial proportion of jockeys failed to meet the estimated average requirement and lower threshold intake for a number of micronutrients. Jockeys consumed well below (0-2) the recommended five daily servings of fruit and vegetables set by the World Health Organization. Pressures of the jockey lifestyle and rigid weight limits appear to encourage unhealthy weight management practices in this group and may risk long term-health.  相似文献   

Business Library Web Sites Revisited: An Updated Review of the Organization and Content of Academic Business Library Web Sites     

Charles Lyons  Hal Kirkwood 《Journal of Business & Finance Librarianship》2013,18(4):333-347

This article updates the findings from a study by Hal Kirkwood in 2000 of the organization and content of academic business library Web sites. The authors examined 75 sites, focusing on five general aspects of the sites: organization, terminology, instructional elements, integration of resources across formats, and annotations. Results of the study show that business library Websites have dramatically improved in the 7 years since the original study.  相似文献   

Print Media     

Oscar Ogg  Douglass McMurtrie  John Adamson  Jim Allee Hart  Louis M. Lyons  Michael L. Johnson 《Communication Booknotes Quarterly》2013,44(5):74-76

Oscar Ogg, The 26 Letters (New York: Crowell, 1971—$7.50)

Douglass McMurtrie with the assistance of John Adamson (eds) The Invention of Printing: A Bibliography (New York: Burt Franklin, 1970—price not known)

Jim Allee Hart, Views on the News: The Developing Editorial Syndrome 1500-1800 (Carbondale: Southern Illinois University Press, 1970—$7.95)

Louis M. Lyons, Newspaper Story: One Hundred Years of the Boston Globe (Cambridge: Harvard University Press, 1971—$9.95)

Michael L. Johnson, The New Journalism: The Underground Press, the Artists of Nonfiction, and Changes in the Established Media (Lawrence: University Press of Kansas, 1971—$6.95/2.95)  相似文献   

BOOK REVIEW     

Frank M. Flanagan  Tony Lyons 《Irish Educational Studies》2013,32(2-3):267-274

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