Sprint running kinematics and kinetics in pre-peak-height-velocity male children on a non-motorised treadmill: reliability and normative data     

Michael Clemens Rumpf  John Cronin  Jonathan Oliver  Michael Hughes 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(3):256-263

The purpose of this study was to quantify the reliability of kinematic and kinetic variables using a sample of pre-peak-height-velocity (PHV) male athletes sprinting on a non-motorised treadmill. Following variables were measured and their normative data presented, average and peak velocity, average and peak power, average and peak horizontal force, average and peak vertical force, average step frequency, average step length, average work. Twenty-five participants performed three 5-s all-out sprints from a standing split start on a non-motorised treadmill on three separate occasions. Per cent change in the means (-3.66 to 3.35%) and coefficients of variation (0.56–7.81%) were thought reliable for all variables. However, average step rate, average horizontal force and average vertical force did not meet the standards (≥0.70) set for acceptable intraclass correlation coefficients (ICC). Due to the homogeneous group, it was expected to receive low ICC values. Therefore, youth sprinting performance can be tested reliably on a non-motorised treadmill, especially if the per cent change in the mean and CV are deemed the important reliability measures. Normative data are given for the participant’s age as well as their maturity level for kinematic and kinetic variables.  相似文献   

Don’t stop make-believing     

Nathan Wildman 《体育哲学杂志》2019,46(2):261-275

ABSTRACT

How is it that we can rationally assert that sport outcomes do not really matter, while also seeming to care about them to an absurd degree? This is the so-called puzzle of sport. The broadly Waltonian solution to the puzzle has it that we make-believe the outcomes matter. Recently, Stear has critiqued this Waltonian solution, raising a series of five objections. He has also leveraged these objections to motive his own contextualist solution to the puzzle. The aim of this paper is to defend the Waltonian solution. The general upshot is that, contra Stear, a make-believe based solution to the puzzle is viable after all.  相似文献   

Muscle force characteristics of male and female collegiate cross-country runners during overground running     

C. Nathan Vannatta  Thomas G. Almonroeder  Thomas W. Kernozek  Stacey Meardon 《Journal of sports sciences》2020,38(5):542-551

ABSTRACT

Males and females demonstrate unique running mechanics that may contribute to sex-related differences in common running related injuries. Understanding differences in muscle forces during running may inform intervention approaches, such as gait retraining addressing muscle force distribution. The purpose of this study was to compare muscle force characteristics and inter-trial variability between males and females during running. Twenty female and 14 male collegiate cross-country runners were examined. Three-dimensional kinetic and kinematic data were collected during overground running and used to estimate muscle forces via musculoskeletal modelling. Principle components analysis was used to capture the primary sources of variance from the muscle force waveforms. The magnitude of the forces for the hamstrings, gastrocnemius, and soleus muscles were higher across the majority of stance in male runners regardless of footstrike pattern. Males also demonstrated greater inter-trial variability in the timing of the peak gluteus maximus force and the magnitude of local peaks in the gastrocnemius force waveform. Male and female collegiate cross-country runners appear to employ unique lower extremity muscle force characteristics during overground running.  相似文献   

On the Boundaries of Framing Terrorism: Guilt,Victimization, and the 2016 Orlando Shooting     

Nathan Walter  Thomas J. Billard  Sheila T. Murphy 《Mass Communication and Society》2017,20(6):849-868

The 2016 Orlando shooting offers an intriguing lens through which to evaluate the boundaries of media frames in the interpretation of terrorism. Using an experimental design (N = 243), the current study investigated the effects of two dominant frames—the homophobic hate crime and the Islamic terrorist frame—on collective guilt, collective victimization, and pro–lesbian, gay, bisexual, transgender, and queer (LGBTQ) political action. In addition, political partisanship and social network diversity were evaluated as potential moderators. Compared to the Islamic terrorist frame, exposure to the homophobic hate crime frame increased collective guilt and decreased collective victimization, subsequently enhancing support for the LGBTQ community. Moreover, social network diversity was shown to override the framing effect, as individuals who reported high diversity were more likely to sign a petition in solidarity with the LGBTQ community, irrespective of frame condition.  相似文献   

Intensive evaluation An example of formative evaluation in curriculum development     

Ruth Zuzovsky  Nathan Orpaz 《Studies in Educational Evaluation》1979,5(3):199-204

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Education of Ethnic and National Minorities in the USSR: a report on current developments     

Nathan Kravetz 《比较教育学》1980,16(1):13-23

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Interaction of wait time feedback and questioning instruction on middle school science teaching     

J. Nathan Swift  C. Thomas Gooding 《科学教学研究杂志》1983,20(8):721-730

Wait time, the duration of teacher pauses after questions, is an important variable in research on science teaching. This project investigated the effects of increasing teacher's wait times on general questioning skills in science teaching. In previous research, the influence of wait time training has been confounded with instruction in general questioning skills, making it difficult to test the hypothesis that increasing the wait time will by itself improve classroom discussions. In this project, these variables were separated through the use of four treatment groups made up of science teachers. One group received instruction in wait time using a newly developed electronic feedback device that monitors the duration of teacher and student pauses; a second group received instruction in general questioning skills; a third group received both types of instruction; a comparison group received no instruction of either type. The tape recordings were coded and analyzed for classroom interaction data. Comparisons were made using discriminant analysis, analyses of variance, and correlational relationships. The wait time feedback devices facilitated the production of wait time means consistently superior to baseline performance, albeit slightly below the 3-second criterion sought. Regardless, the feedback groups did produce a large number of the hypothesized changes. Significant effects were found from a comparison of the discriminant function scores. Effects consistently favored the groups with the feedback devices. The presence of the guides seemed to make little difference. The groups with the devices used greater numbers of high-level questions, especially those of the evaluative level. There were more contributions from students, as measured by length of answers, frequency of volunteered contributions, numbers of relevant student words, and percentages of student talk.  相似文献   

The dilemma of vocational guidance in a time of crisis     

Lothar R. Martin  Nathan Deen 《International journal for the advancement of counseling》1984,7(2):79-86

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Memory and Executive Functioning in 12‐Year‐Old Children With a History of Institutional Rearing          下载免费PDF全文

Johanna Bick  Charles H. Zeanah  Nathan A. Fox  Charles A. Nelson 《Child development》2018,89(2):495-508

We examined visual recognition memory and executive functioning (spatial working memory [SWM], spatial planning, rule learning, and attention shifting) in 12‐year‐olds (n = 150) who participated in the Bucharest Early Intervention Project, a randomized controlled trial of foster care for institutionally reared children. Similar to prior reports at 8 years of age, institutionally reared children showed significant deficits in visual recognition memory and SWM. Deficits in attention shifting and rule learning were also apparent at this time point. These data suggest that early experiences continue to shape the development of memory, learning, and executive functioning processes in preadolescence, which may explain broader cognitive and learning difficulties commonly associated with severe early life neglect.  相似文献   

Editorial     

Nathan Deen 《International journal for the advancement of counseling》1992,15(4):199-200

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