Energy cost of different skating techniques in cross-country skiing     

Millet GP  Boissiere D  Candau R 《Journal of sports sciences》2003,21(1):3-11

The aims of this study were to compare the aerobic energy cost of four 'on-snow' skating techniques in cross-country skiing and to examine the relationships between performance and aerobic energy cost. Twelve male skiers from recreational to national standard performed four level skating trials of 6 min duration in random order, each at the same submaximal velocity but with a different skating technique: (1) 'offset' (V1), using a double asymmetrical and asynchronous pole plant as weight is transferred to one ski; (2) 'two-skate' (V2A), where the pole plant is symmetrical; (3) 'one-skate' (V2), where there is a pole plant as weight is transferred to each ski; and (4) 'conventional', without poles. Oxygen uptake (VO2), pulmonary ventilation, the respiratory exchange ratio and heart rate were measured using a K4(b2) portable gas analyser. The aerobic energy cost (VO2/mean speed) and heart rate were higher (P < 0.05) in the one-skate than in the offset condition. This may be explained by the greater and more efficient use of the upper body and the lower variation in centre of gravity velocity in the offset condition. The aerobic energy cost was 5-9% higher (P < 0.01) in the conventional than in the other techniques, probably because of the shorter duration of propulsive forces within a cycle in the conventional skating condition. Moreover, in ski skating, the mechanical efficiency (propulsive forces/total forces) was shown to be higher in the upper than in the lower limbs. The correlation coefficient between performance and aerobic energy cost was significant in the two-skate (r = 0.68, P = 0.02), one-skate (r = 0.72, P = 0.01) and conventional (r = 0.62, P = 0.04) conditions, but not in the offset condition (r = 0.50, P = 0.10). Our results stress the importance of the upper body component in cross-country skiing and that the aerobic energy cost discriminates between skiers of different standards.  相似文献   

Season-of-birth bias in association football     

Simmons C  Paull GC 《Journal of sports sciences》2001,19(9):677-686

In this longitudinal study, we assessed the frequency of birth dates for boys selected for the Football Association National School. Birthdays were divided into three periods of the year: January to April, May to August and September to December. We compared data over a 5 year period and concluded that there is indeed a bias towards selecting older children. Furthermore, analysis of separate data revealed a shift of bias when comparing two different start dates, namely September and January. Our findings show that the youngest children from the January start date (born September to December) are selected significantly more often than the youngest children from the September start date (born May to August). Interestingly, even when the influence of body mass was reduced, the selection bias towards the older players remained.  相似文献   

HUMAN DEVELOPMENT: SOME CONDITIONS FOR ADULT FAITH AT AGE THIRTY     

Henry C. Simmons C.P. 《Religious education (Chicago, Ill.)》2013,108(6):563-572

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Public Choices and Social Learning: The New Multimedia Technologies in Europe     

Robin Williams 《The Information Society》2000,16(4):251-262

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Talk in Eleven Year Old Children's Response Groups     

Robin J. Dixon 《English in Education》1985,19(2):36-44

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Basecamp     

Robin Featherstone 《Journal of the Medical Library Association》2009,97(1):67

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Checking and adjusting the lens: case study clearance     

Robin Yeomans 《Cambridge Journal of Education》1987,17(2):89-90

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The role of special schools for children with profound and multiple learning difficulties: is segregation always best?     

Ben Simmons  Phil Bayliss 《British Journal of Special Education》2007,34(1):19-24

The education of young people with profound and multiple learning difficulties continues to raise challenges and controversies. In this article, Ben Simmons, an ESRC funded PhD student and research assistant, and Phil Bayliss, programme director for the masters degree in special education and disability, both based in the School of Education and Lifelong Learning at the University of Exeter, describe their research into provision for pupils with profound and multiple learning difficulties in a special school in the south west of England. Their work, based in an interpretivist, qualitative approach, set out to illuminate issues relating to the inclusion of pupils with profound and multiple learning difficulties. The findings presented here suggest that the school, in spite of its strong reputation, struggled significantly to provide appropriate learning experiences for pupils with profound and multiple learning difficulties. Ben Simmons and Phil Bayliss discuss the need for improved staff development opportunities focused on enhancing current levels of knowledge and skills. They conclude by calling for a reappraisal of the established view that special schools necessarily provide the best learning environment for pupils with profound and multiple learning difficulties.  相似文献   

#MeToo,sexual harassment: an article,a forum,and a dream for the future     

Robin Patric Clair  Nadia E. Brown  Debbie S. Dougherty  Hannah K. Delemeester  Patricia Geist-Martin  William I. Gorden 《Journal of Applied Communication Research》2019,47(2):111-129

#MeToo has breathed new life into the women’s movement and especially into understanding and rectifying sexual harassment, abuse and assault. It has galvanized activists around the globe. And it has placed thousands of stories of the harassed in full view of the public. Sexual harassment, abuse and assault may occur within the organizational context or beyond; but sexual harassment, in particular has been legally labeled an organizational phenomenon. With this in mind, Robin Clair frames the early part of this article around the most recent organizational communication theories (see the appendix for an overview of these theories). Following the essay is a forum, in which invited scholars address questions related to the #MeToo movement.  相似文献   

Theoretical Frameworks of Performance‐Based Models     

Robin Tamez 《Performance Improvement》2016,55(6):19-24

The purpose of this article is to highlight theories that support the functions of performance‐based design models and to discuss the implications of integrating divergent models into the system‐oriented human performance technology (HPT) and performance improvement (PI) disciplines. HPT, PI, and instructional systems design (ISD) share a systems framework, along with the influence of common theories such as performance theory, learning theory, adult learning, cognitive psychology, and behavioral psychology (Foshay, Villachica, & Stepich, 2014). This article focuses on the role of theory as a tool in the practitioner's toolbox and as a connection point when working with teams and organizations that have different theoretical orientations. Performance‐based ISD models are discussed, including Robinson and Robinson's (1989) Training for Impact, Brethower and Smalley's (1998) Performance‐Based Instruction, and Bradford and Boler's (2015) Horizon Model. Allen and Sites's (2012) successive approximation model (SAM) retains elements of ADDIE as a process, but the model is iterative rather than systematic in design.  相似文献