Kinematics,coordination, variability,and biological noise in the prone flutter kick at different levels of a “learn-to-swim” programme     

Ross H. Sanders 《Journal of sports sciences》2013,31(2):213-227

Abstract

The purpose of this study was to establish the characteristics of the movement patterns common to flutter kicking of skilled swimmers and to determine how the movement patterns of swimmers at different levels of a “learn-to-swim” programme differ from those of skilled swimmers. Also, the nature of the skill afforded the opportunity to investigate learning of a cyclical multi-joint task from a motor control perspective. The underwater motion of nine children representing three levels of a “learn-to-swim” programme and 10 skilled swimmers were video-recorded while performing nine cycles of prone flutter kicking. Kinematics including joint angular motion and coordination of joint actions were calculated. Fourier analysis was applied to determine the frequency composition of the vertical undulations of the hip, knee, and ankle and to calculate the velocity of the body wave travelling caudally from hip to ankle. Fourier analysis also enabled investigation of biological noise, as distinct from variability. The results indicated the desired joint angles and coordination towards which learners could be guided. An index based on the ratio of hip – knee and knee – ankle body wave velocities showed that the inter-joint coordination of most learners was not appropriate for effective flutter kicking. There was strong evidence to suggest that skilled performance in flutter kicking is characterized by sequencing of joint actions to produce a single sinusoidal body wave moving caudally with not decreasing and preferably increasing velocity, low biological noise, and small variability.  相似文献   

The effect of periodized resistance training on accelerative sprint performance     

Gavin Moir  Ross Sanders  Chris Button  Mark Glaister 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):285-300

The purpose of this study was to assess the effect of periodized resistance training on accelerative sprint performance. Sixteen physically active men participated in a randomized controlled study. An experimental group (n = 10) completed an 8-week periodized resistance training intervention, while a control group (n = 6) did not train. Pre- and post-training measures of 20-m straight-line sprint time, including a 10-m split, maximum strength, and explosive strength, were recorded. Flight time, stance time, stride length, and stride frequency were quantified from digitized video recordings of the first three strides of the 20-m sprint. Resistance training resulted in significant increases in maximum strength (parallel back squat: 19%) and explosive strength (6–10%). However, both groups increased 0–10 m sprint times (experimental group = 6%; control group = 3%) while 10–20 m times were reduced (experimental group = 7%; control group = 4%), highlighting the mechanical differences between the distinct sprint phases. The change during the 0–10 m interval was accompanied by a reduction in stride frequency during the first three strides. Strength coaches should be aware that the potential benefits of increased muscular strength during short sprints are likely to be affected by mechanical specificity and that improvements in sprinting performance may not occur immediately after a period of resistance training.  相似文献   

Is passive drag dependent on the interaction of kayak design and paddler weight in flat-water kayaking?     

Beatriz B. Gomes  Filipe A.V. Conceição  David R. Pendergast  Ross H. Sanders  Mário A.P. Vaz  João Paulo Vilas-Boas 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):394-403

Abstract

Drag is one of the major factors that influences kayaking performance. To focus on the drag of the kayak’s hull shape and the paddlers’ weight per se, the passive drag (D_p) was measured on a flat-water sprint course for one paddler with added weights. D_p was measured by an electromechanical towing device using a load cell, at incremental and constant velocities from 2.78 to 5.56 m/s. Three kayaks of different sizes and shapes (Nelo® K1 Quattro-M, ML, and L) were used and the paddlers’ body weight was adjusted with weights so the total paddler weight in the kayak was 65, 75, and 85 kg. The mean D_p increased by the power function of D = kvⁿ (mean R² = .990; SD .006). The D_p went from 21.37?±?1.29 N at 2.78 m/s to 89.32?±?6.43 N at 5.56 m/s. For the two lighter weighted kayaks (65 and 75 kg), the lowest D_p was observed with different kayak sizes (M, ML, or L) depending on the target velocity. The manufacturers suggest that paddlers should select a kayak size according to their body weight to minimise drag; however, the results of this study suggest that target velocities, and thus competition distance should also be factored into kayak selection.  相似文献   

Predicting acceptance of diversity in pre-kindergarten classrooms     

Kay Sanders  Jason Downer 《Early childhood research quarterly》2012

This study examined classroom-level contributors to an acceptance of diversity in publicly supported pre-kindergarten classrooms across 11 states. Classroom composition, process quality, and teacher characteristics were examined as predictors of diversity-promoting practices as measured by the ECERS-R, acceptance of diversity construct. Findings reveal that emotional climate, bilingual classrooms, family poverty levels within classrooms, and Latino teacher ethnicity are predictive of diversity-promoting classrooms; while classroom-level ethnic sameness to teacher prohibits diversity-promoting practices in pre-kindergarten classrooms.  相似文献   

Bioinformatics Education in High School: Implications for Promoting Science,Technology, Engineering,and Mathematics Careers     

Dina N. Kovarik  Davis G. Patterson  Carolyn Cohen  Elizabeth A. Sanders  Karen A. Peterson  Sandra G. Porter  Jeanne Ting Chowning 《CBE life sciences education》2013,12(3):441-459

We investigated the effects of our Bio-ITEST teacher professional development model and bioinformatics curricula on cognitive traits (awareness, engagement, self-efficacy, and relevance) in high school teachers and students that are known to accompany a developing interest in science, technology, engineering, and mathematics (STEM) careers. The program included best practices in adult education and diverse resources to empower teachers to integrate STEM career information into their classrooms. The introductory unit, Using Bioinformatics: Genetic Testing, uses bioinformatics to teach basic concepts in genetics and molecular biology, and the advanced unit, Using Bioinformatics: Genetic Research, utilizes bioinformatics to study evolution and support student research with DNA barcoding. Pre–post surveys demonstrated significant growth (n = 24) among teachers in their preparation to teach the curricula and infuse career awareness into their classes, and these gains were sustained through the end of the academic year. Introductory unit students (n = 289) showed significant gains in awareness, relevance, and self-efficacy. While these students did not show significant gains in engagement, advanced unit students (n = 41) showed gains in all four cognitive areas. Lessons learned during Bio-ITEST are explored in the context of recommendations for other programs that wish to increase student interest in STEM careers.  相似文献   

Information sources and voting in a primary and general election     

L. Erwin Atwood  Keith R. Sanders 《广播与电子媒介杂志》2013,57(3):291-301

There is a considerable variance in audience perceptions of media use and credibility between primary and general elections. The authors are in the School of Journalism and the Department of Speech, respectively, at Southern Illinois University, Carbondale. They gratefully acknowledge the assistance of Drs. Robert 0. Hirsch and Larry Kokkeler in the collection of data for this report.  相似文献   

The National Convention     

Frank Knight Sanders D.D. 《Religious education (Chicago, Ill.)》2013,108(1):12-14

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The Training of Teachers of Religion in Universities and Colleges     

Frank K. Sanders Ph. D.  D.D. 《Religious education (Chicago, Ill.)》2013,108(2):55-62

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Exposing Student Teachers' Content Knowledge: Empowerment or debilitation?     

Susan E. Sanders  Heather Morris 《Educational studies》2000,26(4):397-408

Previous governments and other commentators have emphasized the relationship between a teacher's knowledge of the subject material being taught and the quality of learning outcomes. This has been reflected in the entry requirements to Initial Teacher Training (ITT) (primary) of public examination performance in the core subjects. However, disquiet has been expressed as to the efficacy of such qualifications as indicators of knowledge and skills at the entry point. Recent changes to ITT (primary) regulations require students' actual knowledge of the content of the three core subjects to be audited. This paper reports and reflects on the effects that re-examining their knowledge and skills in mathematics has had on the confidence of primary trainee teachers. It presents some key questions that must be addressed if the current audit regulations are indeed to benefit our future teachers and to enhance the learning of our pupils.  相似文献   

Internalizing symptoms and affect of children with emotional and behavioral disorders: A comparative study with an urban African American sample     

Deanna E. Sanders  Kenneth W. Merrell  Harriet C. Cobb 《Psychology in the schools》1999,36(3):187-197

Self‐reported internalizing symptoms of seriously emotionally disturbed (SED) and regular education students in grades 4–6 were compared using the Internalizing Symptoms Scale for Children. All participants were African American and from an urban public school district in the Southeastern United States. Each of the two study groups consisted of 50 participants (35 boys, 15 girls) who were matched by gender and socioeconomic status. The SED group reported significantly higher levels of internalizing distress than the regular education group. In contrast to previous findings, there was no significant gender difference in self‐reported internalizing symptomatology in the present study. A discriminant function analysis found that the ISSC scores were able to correctly classify 91% of the participants into their respective educational group. Results of this study provide additional evidence of the construct validity of the ISSC, a recently developed and unique self‐report measure. Results are discussed in terms of future research needs and educational/clinical practice with students who have emotional and behavioral disorders. © 1999 John Wiley & Sons, Inc.  相似文献