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Gavin Moir Ross Sanders Chris Button Mark Glaister 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):285-300
The purpose of this study was to assess the effect of periodized resistance training on accelerative sprint performance. Sixteen physically active men participated in a randomized controlled study. An experimental group (n = 10) completed an 8-week periodized resistance training intervention, while a control group (n = 6) did not train. Pre- and post-training measures of 20-m straight-line sprint time, including a 10-m split, maximum strength, and explosive strength, were recorded. Flight time, stance time, stride length, and stride frequency were quantified from digitized video recordings of the first three strides of the 20-m sprint. Resistance training resulted in significant increases in maximum strength (parallel back squat: 19%) and explosive strength (6–10%). However, both groups increased 0–10 m sprint times (experimental group = 6%; control group = 3%) while 10–20 m times were reduced (experimental group = 7%; control group = 4%), highlighting the mechanical differences between the distinct sprint phases. The change during the 0–10 m interval was accompanied by a reduction in stride frequency during the first three strides. Strength coaches should be aware that the potential benefits of increased muscular strength during short sprints are likely to be affected by mechanical specificity and that improvements in sprinting performance may not occur immediately after a period of resistance training. 相似文献
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Hazel V.J. Moir 《普罗米修斯》2015,33(4):431-443
In 1984, Don Lamberton wrote a two-page disclaimer to a review of the Australian patent system, pointing out that there was nothing economic about the review and that it simply pandered to special interest groups. Some 30 years later, the Productivity Commission has been given a shorter time frame (one year) and a broader remit (all intellectual property). This paper reviews the issues addressed in the Industrial Property Advisory Committee (IPAC) review of 1984. Since it was completed, substantially more empirical evidence has become available, while room for policy improvement has been curtailed by international trade treaties. While the Productivity Commission will take a sound economic approach, the breadth of its remit may prevent full appreciation of the critical issues in patent policy. This paper considers the options remaining to the Commission to recommend improvements in the national interest. Whether these will be taken up depends on the priority given to the interests of small but powerful lobby groups. 相似文献
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Taryn W. Morrissey Kristi S. Lekies Moncrieff M. Cochran 《Early education and development》2007,18(4):617-624
We thank Debra J. Ackerman, Peggy L. Apple, W. Steven Barnett, and Stacie G. Goffin for their thoughtful commentaries on our article “Implementing New York's Universal Pre-Kindergarten Program: An Exploratory Study of Systemic Impacts” (this issue). Our response focuses on two main themes that emerged from the commentaries: (a) the generalizability of the sample and the study's methodological limitations and (b) protectionism of the existing early care and education system. In light of our study and the commentators' main points, we provide a set of policy recommendations for improving quality, accessibility, and affordability in the current early care and education system. 相似文献
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Gavin L. Moir Jared M. Gollie Shala E. Davis John J. Guers Chad A. Witmer 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):492-506
To investigate the effects of different loads on system and lower-body kinetics during jump squats, 12 resistance-trained men performed jumps under different loading conditions: 0%, 12%, 27%, 42%, 56%, 71%, and 85% of 1-repetition maximum (1-RM). System power output was calculated as the product of the vertical component of the ground reaction force and the vertical velocity of the bar during its ascent. Joint power output was calculated during bar ascent for the hip, knee, and ankle joints, and was also summed across the joints. System power output and joint power at knee and ankle joints were maximized at 0% 1-RM (p < 0.001) and followed the linear trends (p < 0.001) caused by power output decreasing as the load increased. Power output at the hip was maximized at 42% 1-RM (p = 0.016) and followed a quadratic trend (p = 0.030). Summed joint power could be predicted from system power (p < 0.05), while system power could predict power at the knee and ankle joints under some of the loading conditions. Power at the hip could not be predicted from system power. System power during loaded jumps reflects the power at the knee and ankle, while power at the hip does not correspond to system power. 相似文献
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This article reports on resistance in primary schools, more specific grade five learners as perceived by teachers. A qualitative phenomenological interpretative approach was followed utilising focus group discussions and individual interviews. Participants included 14 teachers, purposefully selected from three private and three public schools in Gauteng. Data were thematically analysed. Four main themes were identified: 1) manifestations in the classroom differentiated by active or passive resistance, either positive or negative; 2) a causal model of reasoning; 3) teacher-learner relationships affected by negative and positive perceptions; and 4) constructive suggestions for support holding value for practical application. Findings revealed that resistance in the primary school classroom (the result of the interaction between the learner and contextual factors), is still often assumed as negative and dysfunctional to teaching; however, it can equally be conducive and functional depending on the interaction. Teachers display a more flexible, resilient and positive understanding of contributing factors, and they value resistance if it signifies creativity and independent problem solving, leading to more positive teacherlearner relationships. 相似文献
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Taryn Hess Glenda Gunter 《British journal of educational technology : journal of the Council for Educational Technology》2013,44(3):372-385
When combining the increasing use of online educational environments, the push to use serious video games and the lack of research on the effectiveness of online learning environments and video games, there is a clear need for further investigation into the use of serious video games in an online format. A mix methods model was used to triangulate statistical and qualitative findings on student performance, completion time, student intrinsic motivation, as well as desirable, undesirable, helpful and hindering aspects of serious game‐based and nongame‐based courses. Students in the game‐based course were found to have performed significantly better and to have taken significantly longer. Students and teachers in the game‐based course provided more reasons for student motivation along with more desirable, more helpful and less hindering aspects compared to students and teachers in the non‐game‐based course. In addition, students and teachers in both courses provided an equal number of undesirable aspects. The results from this study inform instructional designers, teachers, education stakeholders and educational game designers by providing research‐based evidence related to the learning experiences and outcomes of the serious game‐based online course. 相似文献
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Taryn W. Morrissey 《Child development》2009,80(1):59-76
Nationally, 15% of children younger than 5 years regularly attend more than 1 child-care arrangement. An association between arrangement multiplicity and children's behavior problems has been identified, but previous research may be susceptible to measurement or omitted variable bias. This study used within-child fixed effects models to examine associations between changes in the number of concurrent, nonparental child-care arrangements and changes in mother- and caregiver-reported behavior among 2- and 3-year-old children in the National Institute for Child Health and Human Development Study of Early Child Care and Youth Development ( N = 850). Increases in the number of arrangements were related to increases in children's concurrent behavior problems and decreases in prosocial behaviors, particularly among girls and younger children. Implications for policy and research are discussed. 相似文献
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