Preparation time influences ankle and knee joint control during dynamic change of direction movements     

Patrick Fuerst  Albert Gollhofer  Dominic Gehring 《Journal of sports sciences》2017,35(8):762-768

The influence of preparation time on ankle joint biomechanics during highly dynamic movements is largely unknown. The aim of this study was to evaluate the impact of limited preparation time on ankle joint loading during highly dynamic run-and-cut movements. Thirteen male basketball players performed 45°-sidestep-cutting and 180°-turning manoeuvres in reaction to light signals which appeared during the approach run. Both movements were executed under (1) an easy condition, in which the light signal appeared very early, (2) a medium condition and (3) a hard condition with very little time to prepare the movements. Maximum ankle inversion angles, moments and velocities during ground contact, as well as EMG signals of three lower extremity muscles, were analysed. In 180°-turning movements, reduced preparation time led to significantly increased maximum ankle inversion velocities. Muscular activation levels, however, did not change. Increased inversion velocities, without accompanying changes in muscular activation, may have the potential to destabilise the ankle joint when less preparation time is available. This may result in a higher injury risk during turning movements and should therefore be considered in ankle injury research and the aetiology of ankle sprains.  相似文献   

The power of circulation: digital technologies and the online Chinese fans of Japanese TV drama     

Kelly Hu 《Inter-Asia Cultural Studies》2013,14(2):171-186

Focusing on the online Chinese fans of Japanese TV drama, this paper explores the way in which the fan subculture, in connection with digital technologies, has carved out alternative practices in the circulation, production and consumption of Japanese TV drama. As ‘minority audiences’ who are not targeted as the objects of capitalist interests, online Chinese fans invent spaces for Chinese transnational networking with self‐help and sharing, as a way of resisting the aloofness from marketing strategies of Japanese TV distributors in Asia. This case study reveals that the online Chinese fan clubs, the websites for downloads, pirated VCD markets, digital file conversion, and private VCD burning – all of these have linked endless networks for the digitalized circulation and consumption of Japanese TV drama. The online Chinese fans are guerrilla fighters in the politics of autonomy, network and low‐cost digital technology; they are attempting to break down time–space constraints and the official distribution hierarchy. Such fan practices shed light on the new trends of audio‐visual consumption via digitalization.  相似文献   

Cross-cultural influence on communication effectiveness and user interface design     

Anping Xie  P.-L. Patrick Rau  Yuchien Tseng  Hui Su  Chen Zhao 《Int J Intercult Relat》2009,33(1):11-20

The objective of this study was to investigate the impact of cultural diversity on communication effectiveness with different communication styles and to apply the results in the field of user interface design for computer-based communication systems. The scope of this study was limited to the relationship between context and verbal/nonverbal communication, and also the relationship between power distance and communication interaction. The results indicated that high context people (HCP) had better communication effectiveness in comprehending nonverbal clues than low context people (LCP), while LCP had better communication effectiveness in verbal communication than their counterparts. It was also found that high power distance people (HPDP) could not communicate as effectively as low power distance people (LPDP) during communication with interaction, but there was no significant difference between HPDP and LPDP in dealing with communication without interaction.  相似文献   

Heart rates of high school physical education students during team sports, individual sports, and fitness activities     

Laurson KR  Brown DD  Cullen RW  Dennis KK 《Research quarterly for exercise and sport》2008,79(1):85-91

This study examined how activity type influenced heart rates and time spent in target heart rate zones of high school students participating in physical education classes. Significantly higher average heart rates existed for fitness (142 +/- 24 beats per minute [bpm]) compared to team (118 +/- 24 bpm) or individual (114 +/- 18) activities. Similar results occurred for the percentage of activity time spent within a target heart rate zone (fitness 81.7 +/- 15.9%, individual 68.4 +/- 30.5%, and team 60.6 +/- 30.5%). Boys attained higher heart rates during team activities, while female students had higher rates during individual activities indicating male and female adolescents respond differently to activity types. The highest mean heart rates were observed during fitness activities.  相似文献   

Pedometer reliability, validity and daily activity targets among 10- to 15-year-old boys     

Jago R  Watson K  Baranowski T  Zakeri I  Yoo S  Baranowski J  Conry K 《Journal of sports sciences》2006,24(3):241-251

The aims of this study were to: (1) determine whether the number of pedometer counts recorded by adolescents differs according to the adiposity of the participant or location on the body; (2) assess the accuracy and reliability of pedometers during field activity; and (3) set adolescent pedometer-based physical activity targets. Seventy-eight 11- to 15-year-old Boy Scouts completed three types of activity: walking, fast walking and running. Each type was performed twice. Participants wore three pedometers and one activity monitor during all activities. Participants were divided into groups of normal weight (BMI < 85th percentile) and at risk of being overweight (BMI > or = 85th percentile). Intra-class correlations across the three activities indicated reliability (r = 0.51 - 0.92, P < 0.001). This conclusion was supported by narrow limits of agreement that were within a pre-set range that was practically meaningful. Multivariate analysis of covariance indicated adiposity group differences, but this difference was a function of the increased stature among the larger participants (P < 0.001). Ordinary least-squares regression models and multi-level regression models showed positive associations between the number of pedometer and activity monitor counts recorded by the three groups of participants during all activities (all P < 0.001). The mean number of counts recorded for all participants during the fast walk was 127 counts per minute. In conclusion, the pedometers provided an accurate assessment of adolescent physical activity, and a conservative estimate of 8000 pedometer counts in 60 min is equivalent to 60 min of moderate to vigorous physical activity.  相似文献   

Book reviews     

Finbarré Fitz Patrick  Nicholas Hawkes  James Cummins  Alison M. Pask  Carol Myers Scotton  R. N. Srivastava 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1978,24(3):423-434

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A method of providing accurate velocity feedback of performance on an instrumented kayak ergometer     

Mickaël Begon  Olivier Mourasse  Patrick Lacouture 《Sports Engineering》2009,11(2):57-65

On a kayak ergometer, an accurate simulation of the athlete-paddle-kayak system kinematics is essential for analysing the relationship between technique and performance. The purpose of this study was to establish a strong relationship between performances on flatwater and performances on an ergometer by means of propulsive force measurement and drag models. Two trials were performed by 12 kayakers in which they were first timed over 250 m of flatwater kayaking (the reference test) and were then asked to perform a trial of the same duration on the ergometer with the same perceived physical exertion. Three techniques for measuring propulsive force and three drag models generated nine combinations, which were all evaluated for their ability to estimate kayak velocity. For each combination, the distance covered by the athlete on the ergometer was simulated. A kayakers’ ergometer ranking was based on the average velocity in the ergometer trial. Both distance and ranking were compared to the on-water results. The simulation with the best combination of force measurement and drag model gave an accurate estimate of distance (253 ± 10.5 vs. 250 m) and ranking compared to the reference test.  相似文献   

Student achievement and differential reinforcement of incompatible behavior: Hand raising     

Michael Bryan Kelly  Donald Bushell 《Psychology in the schools》1987,24(3):273-281

Workbook reading achievement of five second-grade girls was assessed under two teacher-contact contingencies. Under one contingency, teacher contacts were made during on-task behavior. Under the other contingency, differential reinforcement of an incompatible behavior (DRI) was in effect, with teacher contacts contingent on students' hand-raising behavior. Both reading achievement and time on task were greater under the on-task contingency than under DRI for hand raising.  相似文献   

The global education industry     

Patrick L. J. Bailey 《教育政策杂志》2017,32(5):718-719

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Creative Library Marketing and Publicity: Best Practices,edited by Robert J. Lackie and M. Sandra Wood     

Kelly A. Clever 《Medical reference services quarterly》2017,36(1):105-106

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