Increasing hip and knee flexion during a drop-jump task reduces tibiofemoral shear and compressive forces: implications for ACL injury prevention training     

Liang-Ching Tsai  Yi-An Ko  Kyle E. Hammond  John W. Xerogeanes  Gordon L. Warren  Christopher M. Powers 《Journal of sports sciences》2017,35(24):2405-2411

Although most ACL injury prevention programmes encourage greater hip and knee flexion during landing, it remains unknown how this technique influences tibiofemoral joint forces. We examined whether a landing strategy utilising greater hip and knee flexion decreases tibiofemoral anterior shear and compression. Twelve healthy women (25.9 ± 3.5 years) performed a drop-jump task before and after a training session (10–15 min) that emphasised greater hip and knee flexion. Peak tibiofemoral anterior shear and compressive forces were calculated using an electromyography (EMG)-driven knee model that incorporated joint kinematics, EMG and participant-specific muscle volumes and patella tendon orientation measured using magnetic resonance imaging (MRI). Participants demonstrated a decrease in peak anterior tibial shear forces (11.1 ± 3.3 vs. 9.6 ± 2.7 N · kg^?1; P = 0.008) and peak tibiofemoral compressive forces (68.4 ± 7.6 vs. 62.0 ± 5.5 N · kg^?1; P = 0.015) post-training. The decreased peak anterior tibial shear was accompanied by a decrease in the quadriceps anterior shear force, while the decreased peak compressive force was accompanied by decreased ground reaction force and hamstring forces. Our data provide justification for injury prevention programmes that encourage greater hip and knee flexion during landing to reduce tibiofemoral joint loading.  相似文献   

Psychometric Properties of a Parental Questionnaire for Assessing Correlates of Toddlers’ Physical Activity and Sedentary Behavior     

Valerie Carson  Kylie D. Hesketh  Ryan E. Rhodes  Christina Rinaldi  Wendy Rodgers  John C. Spence 《Measurement in physical education and exercise science》2017,21(4):190-200

This study examined the psychometric properties of a questionnaire developed with the guidance of the socialization model of child behaviour to understand modifiable correlates of toddlers’ physical activity and sedentary behaviour. Findings are based on 118 parents (33.7 ± 4.9 years; 86% female) of toddlers (19.3 ± 2.7 months; 48% female) from Edmonton, Canada in The Parents’ Role in Establishing healthy Physical activity and Sedentary behaviour habits study (PREPS). The PREPS questionnaire encompassed 21 variables across the constructs of the socialization model of child behaviour. Of the nine variables assessed for internal consistency reliability, eight had good (α ≥ 0.70) reliability. Of the 15 continuous variables assessed for 1-week test–retest reliability, 10 had moderate (intra-class correlation = 0.50–0.74) and 5 had good (intra-class correlation ≥ 0.75) reliability. Of the six categorical variables assessed for 1-week test–retest reliability, two had fair (К = 0.21–0.40), one had moderate (К = 0.41–0.60), one had substantial (К = 0.61–0.80), and two had almost perfect (К = 0.81–1.00) reliability. Of the 12 sedentary behaviour variables assessed for convergent validity, 7 were significantly correlated with children’s screen time, of which three were small (r ≤ 0.29), two were medium (r = 0.30–0.49), and two were large (r ≥ 0.50) effect sizes.  相似文献   

Alcohol sponsorship and its impact on sports participants’ consumption     

Sarah Kelly  Michael Ireland  John Mangan 《Sport in Society》2017,20(7):848-860

The aim of this study was to examine the association between alcohol consumption, alcohol sponsorship in sports and preferences of sponsored sportspeople regarding sponsorships/consumption. We investigate the impact of alcohol sponsorship on sportspeople in the Australian population using a national survey of sportspeople (N?=?2367), representing a range of club and professional sports. The results show an association between alcohol sponsorship of sport and increased alcohol consumption among sports participants (i.e. ‘sportspeople’). Additionally, a preference for sponsored alcohol brands was found by sponsored sportspeople. Our research adds to the growing evidence for policy review of alcohol sponsorship of sports and extends prior studies investigating impacts of alcohol sponsorship upon sports participants by generalizing to a large, national sample of sportspeople.  相似文献   

Books of the Month: Kidvid     

John P. Murray 《Communication Booknotes Quarterly》2013,44(5):50-51

TELEVISION AND BEHAVIOR: TEN YEARS OF SCIENTIFIC PROGRESS AND IMPLICATIONS FOR THE EIGHTIES (Washington: Government Printing Office, 1982—price not given, paper, two vols)

John P. Murray, TELEVISION & YOUTH: 25 YEARS OF RESEARCH & CONTROVERSY (Bowys Town Center for the Study of Youth Development, Research Use and Public Service Division, Boys Town, Neb. 68010—$10.00, paper)

TELEVISION'S IMPACT ON CHILDREN AND ADOLESCENTS: A SPECIAL INTEREST RESOURCE GUIDE IN EDUCATION (Oryx Press, 2214 N. Central at Encanto, Phoenix, Az. 85004—price not given, paper)  相似文献   

Pincher's rock     

John Robinson 《Culture, Theory & Critique》2013,54(1):129-139

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Teacher education students' reflections on how problem‐based learning has changed their mental models about teaching and learning     

Helen Askell‐Williams  Rosalind Murray‐Harvey  Michael J. Lawson 《The Teacher Educator》2013,48(4):237-263

Abstract

Students develop robust mental models of teaching and learning during their school years, and as such, often teach as they were taught—possibly perpetuating practices that limit intellectual inquiry in classrooms. This paper reports on an analysis, using a conceptual framework and NUD?1ST software, of a cohort of 3rd‐year teacher education students' reflections on changes in their mental models following their experiences in a problem‐based learning (PBL) topic. Results provide evidence that students do report changing mental models in areas such as (a) the value of case studies for engaging with subject content, motivating learning, and connecting theory with practice; (b) self‐reflection and peer collaboration for cognitive and professional growth; and (c) processes of inquiry for developing self‐regulated learning practices.  相似文献   

Distance education copyright,intellectual property,and antitrust concerns     

Kenneth D. Smith  John Paul Eddy  Thomas C. Richards  Paul N. Dixon 《The American journal of distance education》2013,27(2):5-13

Abstract

An empirical examination of accredited American higher education institutions was conducted to obtain baseline data regarding distance education copyright, intellectual property, and antitrust concerns. Additionally, a multiple‐case study involving ten of the top thirty accredited distance education institutions in America was conducted. Policy approaches were examined for all institutions, and differences were discussed between public and private institutions as well as between the following Carnegie Classification institutions: Research I and II, Doctorate I and II, and Master's I and II. Data indicated that, out of the schools surveyed, 22% of the institutions in these Carnegie Classification categories published copyright and intellectual property policies on their institution's Web site. In the case study, it was found that 90% of the institutions centrally controlled their distance education program administration as well as the copyright and intellectual property policies related to it.  相似文献   

Scientific concept development in Solomon Island students: a comparative analysis     

John Lowe 《International Journal of Science Education》2013,35(7):743-759

Abstract

This paper summarises the results of an investigation of Solomon Islands secondary school students’ interpretations of three concepts: vision, animals and burning. Internal comparisons among the three areas and external comparisons with findings reported from other societies are made. While some support is given to the idea that children from different cultures may develop similar conceptions, this support is qualified and is shown to be dependent on the type of phenomenon investigated. The degree to which there is immediate personal experience of phenomena may be important, as may the presence or absence of culturally supported explanations. The commonly reported resistance of children's conceptions to school science teaching is also shown not to be universally true. The article ends with a plea for caution in the cross‐cultural extrapolation of research into children's conceptions.  相似文献   

Researching teaching for understanding: the students’ perspective     

John Loughran  Nick Derry 《International Journal of Science Education》2013,35(8):925-938

Abstract

This paper explores high school students’ perspectives of their learning in ascience unit which was taught using a Children's Science approach. Through the use of a questionnaire and interviews, this research examines how the students understood and responded to the changed demands on their learning as a result of the change in teaching style. Although the students appeared to be actively involved, interested and self‐directed in their learning, they were not convinced that this was an appropriate way forthem to approach their learning in future. It appears as though the time and effort associated with accepting more responsibility for learning is not matched by the value received from doing so in schools.  相似文献   

First year juniors and cultural diversity     

John Stringer 《Education 3-13》2013,41(2):21-24

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