An analysis of the relationship between the linear hammer speed and the thrower applied forces during the hammer throw for male and female throwers     

Brice SM  Ness KF  Rosemond D 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(3):174-184

The purpose of this study was to investigate the relationship between the cable force and linear hammer speed in the hammer throw and to identify how the magnitude and direction of the cable force affects the fluctuations in linear hammer speed. Five male (height: 1.88 +/- 0.06 m; body mass: 106.23 +/- 4.83 kg) and five female (height: 1.69 +/- 0.05 m; body mass: 101.60 +/- 20.92 kg) throwers participated and were required to perform 10 throws each. The hammer's linear velocity and the cable force and its tangential component were calculated via hammer head positional data. As expected, a strong correlation was observed between decreases in the linear hammer speed and decreases in the cable force (normalised for hammer weight). A strong correlation was also found to exist between the angle by which the cable force lags the radius of rotation at its maximum (when tangential force is at its most negative) and the size of the decreases in hammer speed. These findings indicate that the most effective way to minimise the effect of the negative tangential force is to reduce the size of the lag angle.  相似文献   

Bowling ball dynamics revealed by miniature wireless MEMS inertial measurement unit   总被引：1，自引：1，他引：0  

Kevin King  N. C. Perkins  Hugh Churchill  Ryan McGinnis  Ryan Doss  Ron Hickland 《Sports Engineering》2011,13(2):95-104

This paper presents a novel sensor technology to deduce the dynamics of a bowling ball. The sensor, a miniature wireless inertial measurement unit (IMU), incorporates MEMS accelerometers and angular rate gyros, a microcontroller, a low power RF transceiver, and a rechargeable battery. When embedded in a bowling ball, the IMU transmits the acceleration and angular velocity data that define the dynamics of the ball starting with the bowler’s delivery and its motion in the lane. Example results from professional bowlers illustrate how this technology can be used to assess bowler skill and ball performance. For instance, the IMU accurately measures the spin dynamics of the ball which are crucial to develop the ball “hook.” An analysis of ball dynamics in the lane is distilled to a measurable “hook potential” metric for further assessing bowler skill. Finally, the sensor presented herein is believed to be the world’s smallest, wireless IMU. This highly miniaturized and wireless design will enable parallel training systems for many sports, including basketball, baseball, crew, cricket, golf, fly fishing, soccer, softball, tennis, rowing, among others.  相似文献   

Golf styles and centre of pressure patterns when using different golf clubs     

Ball KA  Best R 《Journal of sports sciences》2011,29(6):587-590

When using a driver, the centre of pressure of a golfer shows a pattern that is characteristic of one of two distinct swing styles: the "front foot" style or the "reverse" style. The aim of this study was to establish whether these two swing styles are also evident when using other clubs, and if so, to determine whether golfers use the same swing style when using different clubs. Forty-six professional, amateur, and recreational golfers performed swings to hit a ball into a net placed 3 m away. Ten swings were performed for each of the driver, 3-iron, and 7-iron while standing on two force plates. The position of the golfer's centre of pressure parallel with the line of shot and relative to the feet was quantified at eight swing events that were identified from 200-Hz video. Cluster analysis confirmed that the front foot and reverse styles were evident in all three clubs, and most of the golfers (96%) used the same swing style for all three clubs. Golfers that used the reverse swing positioned their centre of pressure nearer to their toes at ball contact compared with golfers that used the front foot swing.  相似文献   

The long-term athlete development model: physiological evidence and application   总被引：2，自引：2，他引：0  

Ford P  De Ste Croix M  Lloyd R  Meyers R  Moosavi M  Oliver J  Till K  Williams C 《Journal of sports sciences》2011,29(4):389-402

Within the UK, the "Long Term Athlete Development" (LTAD) model has been proposed by a variety of national governing bodies to offer a first step to considering the approach to talent development. The model, which is primarily a physiological perspective, presents an advancement of understanding of developing athletic potential alongside biological growth. It focuses on training to optimize performance longitudinally, and considers sensitive developmental periods known as "windows of opportunity". However, it appears that there are a number of problems with this theoretical model that are not necessarily transparent to coaches. Principally, the model is only one-dimensional, there is a lack of empirical evidence upon which the model is based, and interpretations of the model are restricted because the data on which it is based rely on questionable assumptions and erroneous methodologies. Fundamentally, this is a generic model rather than an individualized plan for athletes. It is crucial that the LTAD model is seen as a "work in progress" and the challenge, particularly for paediatric exercise scientists, is to question, test, and revise the model. It is unlikely that this can be accomplished using classical experimental research methodology but this should not deter practitioners from acquiring valid and reliable evidence.  相似文献   

Successful Concurrent Programs: An EXCELerate Program in Oklahoma     

Juanita Gamez Vargas  Rick Roach  Kevin M. David 《Community College Journal of Research & Practice》2014,38(2-3):166-173

The article presents the implementation and findings of a successful collaborative effort with the Oklahoma State Regents for Higher Education (OSRHE), Tulsa Community College (TCC), and two local public school districts, Tulsa Public Schools (TPS) and Union Public Schools (UPS). Known as EXCELerate, it's a five-semester dual enrollment pilot program that received state policy exceptions for juniors and seniors to enroll in dual enrollment courses and supportive resources from the participating agencies. Whereas the traditional dual enrollment student is White and college-going, the program's intent was to increase the number of high school students who may be first-generation, lower-socioeconomic, ethnic or non-ethnic. The article identifies three major barriers to successful dual enrollment and completion: state policy, financial issues, and transportation. It also examines how these barriers were eliminated through a collaborative effort. The results demonstrate that over 87% of the juniors and seniors persisted over the semesters, and enrollment tripled among African American and Latino students. The article is constructed to benefit further research and practical application for urban and rural community colleges.  相似文献   

An Investigation of Media Influences on Elementary Students Representations of Scientists     

Donna Farland-Smith  Kevin Finson  William J. Boone  Melissa Yale 《Journal of Science Teacher Education》2014,25(3):355-366

Even long before children are able to verbalize which careers may be interesting to them, they collect and store ideas about scientists. For these reasons, asking children to Draw-A-Scientist has become an accepted method to provide a glimpse into how children represent and identify with those in the science fields. Years later these representations may translate into student’s career choice. Since 1995, children’s illustrations of scientists have been assessed by the Draw-A-Scientist Checklist (DAST-C). The checklist was created from the common aspects or features found in illustrations from previous studies and were based initially on the scientists, broken down into “stereotypical” and “alternative” images shown in the drawings. The purpose of this paper is to describe the development, field test and reliability of the modified Draw-A-Scientist Test (DAST) and The Draw-A-Scientist Rubric designed as an improvement of the DAST-C to provide a more appropriate method of assessing students’ drawings of scientists. The combination of the modified DAST and the DAST Rubric brings more refinement as it enables clarities to emerge and subsequently increased detail to what one could ascertain from students about their mental images of scientists.  相似文献   

Editorial     

Kevin Leander 《Learning, Media and Technology》2014,39(4):405-408

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Anatomy integration blueprint: A fourth‐year musculoskeletal anatomy elective model          下载免费PDF全文

Michelle D. Lazarus  Gordon L. Kauffman Jr.  Milind J. Kothari  Timothy J. Mosher  Matthew L. Silvis  John R. Wawrzyniak  Daniel T. Anderson  Kevin P. Black 《Anatomical sciences education》2014,7(5):379-388

Current undergraduate medical school curricular trends focus on both vertical integration of clinical knowledge into the traditionally basic science‐dedicated curricula and increasing basic science education in the clinical years. This latter type of integration is more difficult and less reported on than the former. Here, we present an outline of a course wherein the primary learning and teaching objective is to integrate basic science anatomy knowledge with clinical education. The course was developed through collaboration by a multi‐specialist course development team (composed of both basic scientists and physicians) and was founded in current adult learning theories. The course was designed to be widely applicable to multiple future specialties, using current published reports regarding the topics and clinical care areas relying heavily on anatomical knowledge regardless of specialist focus. To this end, the course focuses on the role of anatomy in the diagnosis and treatment of frequently encountered musculoskeletal conditions. Our iterative implementation and action research approach to this course development has yielded a curricular template for anatomy integration into clinical years. Key components for successful implementation of these types of courses, including content topic sequence, the faculty development team, learning approaches, and hidden curricula, were developed. We also report preliminary feedback from course stakeholders and lessons learned through the process. The purpose of this report is to enhance the current literature regarding basic science integration in the clinical years of medical school. Anat Sci Educ 7: 379–388. © 2014 American Association of Anatomists.  相似文献   

Identifying Key Features of Effective Active Learning: The Effects of Writing and Peer Discussion     

Debra L. Linton  Wiline M. Pangle  Kevin H. Wyatt  Karli N. Powell  Rachel E. Sherwood 《CBE life sciences education》2014,13(3):469-477

We investigated some of the key features of effective active learning by comparing the outcomes of three different methods of implementing active-learning exercises in a majors introductory biology course. Students completed activities in one of three treatments: discussion, writing, and discussion + writing. Treatments were rotated weekly between three sections taught by three different instructors in a full factorial design. The data set was analyzed by generalized linear mixed-effect models with three independent variables: student aptitude, treatment, and instructor, and three dependent (assessment) variables: change in score on pre- and postactivity clicker questions, and coding scores on in-class writing and exam essays. All independent variables had significant effects on student performance for at least one of the dependent variables. Students with higher aptitude scored higher on all assessments. Student scores were higher on exam essay questions when the activity was implemented with a writing component compared with peer discussion only. There was a significant effect of instructor, with instructors showing different degrees of effectiveness with active-learning techniques. We suggest that individual writing should be implemented as part of active learning whenever possible and that instructors may need training and practice to become effective with active learning.  相似文献   

Nutrition for the sprinter     

Tipton KD  Jeukendrup AE  Hespel P;International Association of Athletics Federations 《Journal of sports sciences》2007,25(Z1):S5-15

The primary roles for nutrition in sprints are for recovery from training and competition and influencing training adaptations. Sprint success is determined largely by the power-to-mass ratio, so sprinters aim to increase muscle mass and power. However, extra mass that does not increase power may be detrimental. Energy and protein intake are important for increasing muscle mass. If energy balance is maintained, increased mass and strength are possible on a wide range of protein intakes, so energy intake is crucial. Most sprinters likely consume ample protein. The quantity of energy and protein intake necessary for optimal training adaptations depends on the individual athlete and training demands; specific recommendations for all sprinters are, at best, useless, and are potentially harmful. However, if carbohydrate and fat intake are sufficient to maintain energy levels, then increased protein intake is unlikely to be detrimental. The type and timing of protein intake and nutrients ingested concurrently must be considered when designing optimal nutritional strategies for increasing muscle mass and power. On race day, athletes should avoid foods that result in gastrointestinal discomfort, dehydration or sluggishness. Several supplements potentially influence sprint training or performance. Beta-alanine and bicarbonate may be useful as buffering agents in longer sprints. Creatine may be efficacious for increasing muscle mass and strength and perhaps increasing intensity of repeat sprint performance during training.  相似文献