The kinematic differences between off-spin and leg-spin bowling in cricket     

Aaron J. Beach  René E. D. Ferdinands  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(3):295-313

Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.  相似文献   

Observed Implementation of a Science Professional Development Program for K-8 Classrooms     

Becky Barton Sinclair  Gilbert Naizer  Cynthia Ledbetter 《Journal of Science Teacher Education》2011,22(7):579-594

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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   

The application of inertial measurement units and functional principal component analysis to evaluate movement in the forward 3½ pike somersault springboard dive     

Cherie Walker  John Warmenhoven  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(2):146-162

Based on technological and analytical advances, the capability to more accurately and finitely examine biomechanical and skill characteristics of movement has improved. The purpose of this study was to use Inertial Measurement Units (IMUs) and Functional Principal Components Analysis (fPCA) to examine the role of movement variability (assessed via angular velocity), on 2 divers (1 international level; 1 national) performing the forward 3½ pike somersault dive. Analysis of angular velocity curves during ive-flight identified 5 fPCs, accounting for 96.5% of movement variability. The national diver’s scatter plots and standard deviation of fPC scores illustrated larger magnitudes of angular velocity variability across dive flight. For fPC1 and fPC3, magnitudes of SD variability were 282.6 and 201.5, respectively. The international diver illustrated more consistent angular velocity profiles, with clustering of fPCs scores (e.g., fPC1 & 3 = SD’s of 75.2 & 68.0). To account for lower variability in the international diver, the ability to better coordinate movement sequences and functionally utilise feedback in response to initiation of the somersault position is highlighted. Overall, findings highlight how both IMUs and fPCA can more holistically and finitely examine the biomechanical and skill characteristics of movement sequences with the capability to inform athlete development.  相似文献   

Jewish Orientation in the Nursery School Program     

Alex Sinclair 《Journal of Jewish Education》2013,79(1-2):40-50

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Use of clustering techniques in deriving psychoeducational profiles     

Esther Sinclair  Leeka Kheifets 《Contemporary educational psychology》1982,7(1):81-89

This study explores whether a synthesis of clinical and statistical data taken from the psychoeducational reports completed on a group of 42, 9- to 11-year-old boys referred to a Child Psychiatric Outpatient Department for school-learning problems, would yield discrete clinical categories or clusters of children. An amalgamated hierarchical clustering technique which formed clusters by subjects based on a measure of euclidean distance was used. Forty-two reports were evaluated by licensed educational psychologists in five input areas: Developmental History, School History, Cognitive Functioning, Sensorimotor/Perceptual Functioning, and Academic Achievement. One of three educational placement recommendations was identified for each subject: No Educational Placement Intervention Necessary, Special Tutoring or Remediation, and Special Class Placement. Using clinical characteristic ratings given by the evaluators on each variable, a similarity-dissimilarity matrix was formed which classified subjects into four discrete clusters based on their clinical profiles. A χ² test determined that there was a significant association (p < .01) between cluster membership and educational placement recommendations.  相似文献   

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   

Journey around Leadership     

Amanda Sinclair 《Discourse: Studies in the Cultural Politics of Education》2004,25(1):7-19

Ideas about leadership in education, as in other areas of professional practice, increasingly borrow from management and business thinking. In this article I provide a commentary and critique of contemporary leadership in the form of a narrative of my own experience as an educator in a business school. My experience as a woman teacher of largely male, adult management students has underscored my learning about and critique of leadership theory and my own aspirations as teacher and leader. Personal experience is interwoven with theoretical commentary to highlight the limitations of leadership discourses—too often disembodied, de‐gendered and de‐sexualized. By inserting my responses and feelings I also seek to subvert, or at least to add some different dimensions to, intellectualized and inert critiques of leadership. Learning about leadership, including engagement, reaction and contestation, is not just a cerebral undertaking, but emotion laden and thoroughly embodied. I sought to reflect these qualities in this article.  相似文献   

Constructing and understanding of place value in numerical notation     

Anne Sinclair  Anne Garin  Chantal Tièche-Christinat 《European Journal of Psychology of Education - EJPE》1992,7(3):191-207

The purpose of this study was to investigate how children aged five to nine gradually build up an understanding of the characteristics of place-value inherent in the written number system. The task consisted in presenting collections of chips, asking children to produce the corresponding two-digit numerals, and then questioning them in a structured clinical interview about the possible numerical meaning (in terms of correspondence to a number of chips) of each of the digits in the numeral. Results show that the idea that parts of the notation must correspond to mutually exclusive parts of the collection is but slowly built up, and that subsequently it is fleshed out by the use of knowledge concerning oral numeration_— written numeration correspondences. Intuitions concerning «groups of ten» arise later. A fair proportion of eight-year-olds and all nine-years-olds saw the two-digits as corresponding to, on the one hand, a number of units, and on the other, a number of groups of units.  相似文献   

Children in care or in need: educational progress at home and in care     

Ian Sinclair  Nikki Luke  David Berridge 《牛津教育评论》2019,45(4):443-460

ABSTRACT

By age 16 the attainment of most children in or on the edge of out of home care has fallen well behind the average for their age. This paper uses the English National Pupil Database to examine how much of this falling behind occurs before the age of seven, and how any subsequent decline relates to time in care as against time outside it. We compare the previous progress of three groups of 16-year-olds: 5175 looked after by the state (CLA), 17,392 in need but not in care (CIN), and 22,567 children matched with the CLA or CIN on initial attainment, special educational needs, and eligibility for free school meals. We found that the attainment of the CIN and those CLA not yet in care was around one standard deviation below the cohort average at age seven. It then fell relative to their peers while their rate of unauthorised absences and exclusions grew. Removal from home to care appeared to halt or greatly reduce this decline but did not, on average, reverse it. We conclude that educational interventions for CLA should also include CIN, start before seven, target both school and family, and exploit the educational opportunity which care provides.  相似文献