Measurement Errors in Modified Pull-Ups Testing     

Jo Ann Kollath  Margaret J. Safrit  Weimo Zhu  Long-Guang Gao 《Research quarterly for exercise and sport》2013,84(4):432-435

In a review of 46 meta-analyses of gender differences, overhand throwing had the largest gender difference favoring boys (ES > 3.0). Expectations for gender-specific performances may be less pronounced in female Australian Aborigines, because historical accounts state they threw for defense and hunting. Overhand throwing velocities and kinematics were recorded in 30 female and male Aboriginal Australian children 6-10 years old. Results indicated the Aboriginal girls and boys were more similar in horizontal ball velocities than U.S. girls and boys. Throwing kinematics between girls and boys were also more similar in Australian Aborigines than U.S. children. Aboriginal girls threw with greater velocities than U.S., German, Japanese, and Thai girls, while the boys were similar across cultures.  相似文献   

Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise     

E. V. Lambert  J. A. Hawley  J. Goedecke  T. D. Noakes  S. C. Dennis 《Journal of sports sciences》2013,31(3):315-324

Carbohydrate ingestion before and during endurance exercise delays the onset of fatigue (reduced power output). Therefore, endurance athletes are recommended to ingest diets high in carbohydrate (70% of total energy) during competition and training. However, increasing the availability of plasma free fatty acids has been shown to slow the rate of muscle and liver glycogen depletion by promoting the utilization of fat. Ingested fat, in the form of long-chain (C 16-22 ) triacylglycerols, is largely unavailable during acute exercise, but medium-chain (C 8-10 ) triacylglycerols are rapidly absorbed and oxidized. We have shown that the ingestion of medium-chain triacylglycerols in combination with carbohydrate spares muscle carbohydrate stores during 2 h of submaximal (< 70% VO 2 peak) cycling exercise, and improves 40 km time-trial performance. These data suggest that by combining carbohydrate and medium-chain triacylglycerols as a pre-exercise supplement and as a nutritional supplement during exercise, fat oxidation will be enhanced, and endogenous carbohydrate will be spared. We have also examined the chronic metabolic adaptations and effects on substrate utilization and endurance performance when athletes ingest a diet that is high in fat (> 70% by energy). Dietary fat adaptation for a period of at least 2-4 weeks has resulted in a nearly two-fold increase in resistance to fatigue during prolonged, low- to moderate-intensity cycling (< 70% VO 2 peak). Moreover, preliminary studies suggest that mean cycling 20 km time-trial performance following prolonged submaximal exercise is enhanced by 80 s after dietary fat adaptation and 3 days of carbohydrate loading. Thus the relative contribution of fuel substrate to prolonged endurance activity may be modified by training, pre-exercise feeding, habitual diet, or by artificially altering the hormonal milieu or the availability of circulating fuels. The time course and dose-response of these effects on maximizing the oxidative contribution of fat for exercise metabolism and in exercise performance have not been systematically studied during moderate- to high-intensity exercise in humans.  相似文献   

Young people,social media and health     

Jo Hickman Dunne 《Sport, Education and Society》2013,18(9):1019-1022

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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   

Training priority: Positive suggestions     

Jo Kuykendall 《Early Childhood Education Journal》1992,19(4):25-27

“Keep the sand low, Mike, so it doesn't accidentally get in someone's eyes. That would hurt. Yes, like that — you and Jonathan are building some very long roads. Would a little water help you pack them smoothly?” This teacher's tone of voice is accepting, and her words show understanding of the lifelong learning process.  相似文献   

世界著名沉船事件之一玛丽号     

Andrew Lambert 《海外英语》2006,(3):8-9

1545年“玛丽·罗斯”号在海港沉没。然而, 50年前,她却是亨利八世舰队的骄傲。  相似文献   

Validation and profile of Chinese pre-service teachers’ technological pedagogical content knowledge scale     

Guoyuan Sang  Jo Tondeur  Ching Sing Chai 《Asia-Pacific Journal of Teacher Education》2016,44(1):49-65

Researchers state that teachers in different contexts reported different technological pedagogical content knowledge (TPACK). This phenomenon may partially be explained by cultural differences. Based on this consideration, the development and validation of the Chinese pre-service teachers’ technological pedagogical content knowledge (CTPCK) scale is described in this article. The sample was split into two subsamples on random basis (n1 = 229, n2 = 207) for the purpose of conducting (1) exploratory factor analysis (EFA) and (2) confirmatory factor analysis (CFA), respectively. After the EFA, the CTPCK scale excluded six items and included eight factors with 42 items. Reliability and correlations were discussed. The findings revealed that the CTPCK scale was a valid and reliable instrument for measuring the TPACK of Chinese pre-service teachers’ knowledge with or without linking educational technology.  相似文献   

Essential Conditions for Technology-Supported,Student-Centered Learning: An Analysis of Student Experiences With Math Out Loud Using the ISTE Standards for Students     

Mary Jo Dondlinger  Julie McLeod  Sheri Vasinda 《Journal of Research on Technology in Education》2016,48(4):258-273

This article explores links between student experiences with technology-rich mathematics instruction and the ISTE Standards for Students. Research methods applied constructivist grounded theory to analyze data from student interviews against the ISTE Standards for Students to identify which elements of the design of this learning environment seemed to support the attainment of both mathematics content objectives and the ISTE Standards for Students. Researchers then identify guiding principles for the effective design of technology-supported, student-centered learning environments based on analysis of the results. (Keywords: ISTE standards, mathematics education, student- created work, technology-rich learning)  相似文献   

Volume contents     

Jo Boaler 《Educational Studies in Mathematics》2002,50(3):347-348

Volume Contents

Volume contents  相似文献   

Attitude items and low ability students: the need for a cautious approach to interpretation     

Michela Gnaldi  Ian Schagen    Jo Morrison 《Educational studies》2005,31(2):103-113

The results of the Progress in International Reading Literacy Study (PIRLS 2001) were published in 2003. In addition to data about the reading achievements of 10‐year‐olds in 35 countries, PIRLS 2001 also collected questionnaire information from children, their teachers, headteachers and parents. The results showed not just how well students can perform in various reading tasks, but also the relationship between reading abilities and other characteristics, including the characteristics of their homes and schools, the students' attitudes to reading, reading enjoyment, self‐confidence, engagement and perceptions of their reading abilities. Surprisingly enough, children in England were reported as having poor attitudes to reading, compared to children in many other countries, despite high achievement on the reading tests. This paper raises some concerns about the interpretation of results from the study, suggesting a more complex picture than that presented in the summary index published in 2003. Our secondary analysis of the attitude and achievement data from PIRLS shows that pupils with low ability levels have misunderstood the questions which tested their attitudes towards reading. The authors point out that caution is needed when making cross‐country comparisons to avoid naïve approaches to interpretation.  相似文献