The kinematic differences between accurate and inaccurate squash forehand drives for athletes of different skill levels     

Benjamin K. Williams  Ross H. Sanders  Joong Hyun Ryu  Philip Graham-Smith  Peter J. Sinclair 《Journal of sports sciences》2020,38(10):1115-1123

ABSTRACT

To maintain the accuracy of squash shots under varying conditions, such as the oncoming ball’s velocity and trajectory, players must adjust their technique. Although differences in technique between skilled and less-skilled players have been studied, it is not yet understood how players vary their technique in a functional manner to maintain accuracy under varying conditions. This study compared 3-dimensional joint and racket kinematics and their variability between accurate and inaccurate squash forehand drives of 9 highly skilled and 9 less-skilled male athletes. During inaccurate shots, less-skilled players hit the ball with a more open racket, demonstrating a difference in this task-relevant parameter. No joint kinematic differences were found for accuracy for either group. Coordinated joint rotations at the elbow and wrist both displayed a “zeroing-in” effect, whereby movement variability was reduced from the initiation of propulsive joint rotation to a higher consistency at ball-impact; potentially highlighting the “functionality” of the variability prior to the impact that enabled consistent task-relevant parameters (racket orientation and velocity) under varying conditions. Further, highly skilled players demonstrated greater consistency of task-relevant parameters at impact than less-skilled players. These findings highlight the superior ability of highly skilled players to adjust their technique to achieve consistent task-relevant parameters and a successful shot.  相似文献   

Evaluating the potential of teacher-designed technology-based tasks for meaningful learning: Identifying needs for professional development     

Ann George  Martie Sanders 《Education and Information Technologies》2017,22(6):2871-2895

With technology increasingly being introduced into classrooms worldwide, stakeholders are asking whether ICT provides educational value. It is not simply having access to technology but how teachers use it that will determine its worth to education. Thirty-three teacher-designed technology-based tasks from eight subject areas were analysed for their effective use of ICT, and their potential to involve students in constructivist learning. Few of the tasks made effective use of ICT for meaningful learning, for reasons associated with teachers’ beliefs, attitudes, and missing TPACK components or competencies. These factors provide the basis for a model of areas to target when structuring professional development courses to help teachers better utilize educational ICT to design meaningful learning tasks.  相似文献   

Self-help groups in illness and bereavement     

Bernardi JM  Sanders CM 《Death education》1978,2(3):311-317

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The ontogeny of the feature-positive effect in young chicks     

James S. Miller  Sanders A. McDougall  James F. Zolman 《Learning & behavior》1988,16(2):195-198

The wide generality of the feature-positive effect (FPE) has caused speculation that the FPE may represent innate biases in the stimulus control of discriminative responding. There is little experimental evidence to date ragarding this possibility. In the present study, 1- or 4-day-old chicks were trained on a feature-positive (FP) or feature-negative (FN) discrimination with heat reinforcement. After the acquisition phase, these subjects received extinction training followed by a reacquisition phase. The FP performance was superior to the FN performance in both age groups. Extinction resulted in improved discrimination performance in both the FP and FN conditions. Unmasking of FN learning by the extinction treatment suggests that the FPE represents a deficit in performance, rather than an inability to learn the FN task. These data demonstrate that adult-like performance on feature discriminations is evident as early as the first day post-hatch.  相似文献   

The reading rate and comprehension of adults with impaired reading skills or visual discomfort     

Elizabeth Conlon  Mary Sanders 《Journal of Research in Reading》2011,34(2):193-214

The purpose of this study was to investigate the effect of impaired reading skills and visual discomfort on the reading rate and comprehension of university students when reading texts presented at a high school (Grade 9) or university (Grade 12) level of difficulty. Groups included impaired readers (n=18) and normal readers with (n=13) or without visual discomfort (n=19). Regardless of text difficulty the impaired reader group had a significantly slower reading rate and poorer comprehension than the normal reader control group. However, when reading rate and comprehension were compared at the assessed reading level of each group, no group differences were found. The normal reading visual discomfort group had poorer reading comprehension than other normal readers with presentation of university‐level text only. It was concluded that poor word decoding skills may exacerbate comprehension difficulties in impaired readers. In contrast, the comprehension difficulties found for normal readers with visual discomfort occurred because of the somatic and perceptual difficulties induced with exposure to the repetitive striped patterns found on text pages. The types of strategy needed to increase the reading efficiency and produce greater academic success in university students with impaired reader skills or visual discomfort are discussed.  相似文献   

Reliability and validity of field-based fitness tests in youth soccer players     

James H. Dugdale  Calum A. Arthur  Dajo Sanders  Angus M. Hunter 《European Journal of Sport Science》2019,19(6):745-756

This study aimed to establish between-day reliability and validity of commonly used field-based fitness tests in youth soccer players of varied age and playing standards, and to discriminate between players without (“unidentified”) or with (“identified”) a direct route to professional football through their existing club pathway. Three-hundred-and-seventy-three Scottish youth soccer players (U11–U17) from three different playing standards (amateur, development, performance) completed a battery of commonly used generic field-based fitness tests (grip dynamometry, standing broad jump, countermovement vertical jump, 505 (505COD) and T-Drill (T-Test) change of direction and 10/20 m sprint tests) on two separate occasions within 7–14?days. The majority of field-based fitness tests selected within this study proved to be reliable measures of physical performance (ICC?=?0.83–0.97; p?p?2 (7)?=?101.646, p?相似文献   

Static and dynamic accuracy of a magnetic-inertial measurement unit used to provide racket swing kinematics     

Benjamin Kane Williams  Ross H. Sanders  Joong Hyun Ryu  Pitre C. Bourdon  Philip Graham-Smith  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(2):202-214

Magnetic-inertial measurement units (MIMUs) are becoming more prevalent in sports biomechanics and may be a viable tool to evaluate kinematic parameters. This study examined the accuracy of a MIMU to estimate orientation angles under static conditions and dynamically from a squash racket during a forehand drive shot. A MIMU was mounted onto a goniometer and moved through 0–90°, with static data collected at 10° increments during 10 repetitions of all three axes. Typical error analyses showed the MIMU to be very reliable (TE ≤ 0.03°). MIMU accuracy was determined via intraclass correlation coefficients (ICC) (r > 0.999, p < 0.001). An ordinary least products regression showed no proportional bias and minimal fixed bias for all axes. Dynamic accuracy was assessed by comparing MIMU and optical motion capture data of squash racket swing kinematics. A MIMU was fixed onto a racket and 10 participants each hit 10 forehand shots. Mean orientation angle error at ball impact was <0.50° and ICC showed very high correlations (r ≥ 0.988, p < 0.001) for all orientations. Swing phase root mean squared errors were ≤2.20°. These results indicate that a MIMU could be used to accurately and reliably estimate selected racket swing kinematics.  相似文献   

Almost Astronauts and the Pursuit of Reliability in Children’s Nonfiction     

Joe Sutliff Sanders 《Children‘s Literature in Education》2015,46(4):378-393

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Students selling sex: marketisation,higher education and consumption     

Teela Sanders  Kate Hardy 《British Journal of Sociology of Education》2015,36(5):747-765

Robust academic research on the topic of students involved in the sex industry is in its infancy, yet the relationship appears consistent and permanent. This paper draws on findings from the largest study into the stripping industry in the United Kingdom to explore the relationships between students, sex work and consumption. To make sense of the relationship between students and participation in the sex industry, a deeper understanding of other social and cultural processes is needed. In this discussion we argue that the following points are relevant and interlinked: changes to the nature of sexual commerce and sexual consumption as they become part of the marketplace; changes in social attitudes and the rise of ‘respectability’ in sexual commerce; the ‘pleasure dynamic’ amongst students; and changes in the higher education structure that place students as consumers as well as financially fragile. We set out a future research agenda given that this relationship is set to grow as the individual bares the cost of higher education.  相似文献   

Small Robot Projects: Before You Start     

Robert McCartney  Kathryn E. Sanders 《Computer Science Education》2013,23(1):56-63

Working with robots is an attractive possibility for educators at many levels. The price and availability of robotic hardware are favorable, there are often examples in the media of school groups doing robotic projects, and the projects support group design and co-operative activity. Still, these projects cannot be organized without considerable effort. In this article, we look at some of the opportunities and pitfalls that are encountered when working with robots in an educational setting, illustrating them with anecdotes from our experience with eight small robot-building projects, with participants ranging in age from nine to adult, and duration ranging from a single day to a full semester. We suggest some of the benefits of these projects and outline the problems organizers and participants will be likely to face.  相似文献