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31.
This paper studies the publication productivity of inbreds and non‐inbreds among Russian academics. Existing literature provides ambiguous results on the relationship between inbred status and productivity. This may be explained by the use of different indicators for measuring publication productivity. We use data, which include indicators of both current publication productivity (at a certain point of time) and cumulative productivity (throughout the career) to identify whether inbreds and non‐inbreds differ in their productivity. We did not find any difference in current publication productivity of inbreds and non‐inbreds. We found, however, a difference in their cumulative publication productivity: non‐inbreds are being more productive on an individual level throughout their careers. Although the conclusions are based on the Russian data, the analysis provides an explanation for existing contradictory results on the relationship between academic inbreeding and productivity in general.  相似文献   
32.
The study's purpose was to identify the mediating role of intention and the stages of change (SOC) in physical activity (PA) over a 6-month period using two models (theory of planned behavior [TPB] and TPB/SOC). Participants were 143 adults with physical disabilities (70.68% response rate; M age = 46.03). The TPB constructs, SOC (time 1), and PA (time 2) were assessed using standardized self-report questionnaires. Based on path analyses, attitude had the highest effect on intention and SOC followed by perceived behavioral control within both well-fit models. The variance in PA explained by the first (TPB) and second (TPB/SOC) models was 16% and 28% respectively. In the just identified model of TPB/SOC, the direct effect of SOC on physical activity remained strong (gamma(soc.pa) = .45) and SOC approached full mediation through attitude. Health promotion interventions need to include both intention and behavior elements (SOC) reinforcing increased PA value and barrier elimination.  相似文献   
33.
The aim of this cross-sectional study was to compare bone mass in young female athletes playing ball games on different types of playing surfaces. About 120 girls, 9–13 years of age (10.6 ± 1.5 years old Tanner I–III) were recruited and divided into prepubertal and pubertal groups. The sample represented 3 groups of athletes: soccer (N = 40), basketball (N = 40), and handball (N = 40); and 6 different playing surfaces (soccer – ground, soccer – artificial turf, basketball – synthetic, basketball – parquet, handball – synthetic, and handball – smooth concrete). Total and regional body composition (bone mass, fat mass, and lean mass) were measured by dual-energy X-ray absorptiometry (DXA). The mechanical properties of the surfaces (force reduction, vertical deformation, and energy return) were measured with the Advanced Artificial Athlete (Triple A) method. The degree of sexual development was determined using Tanner test. The pubertal group showed that soccer players on the ground, basketball players on synthetic, and handball players on smooth concrete had higher values of bone mineral content (BMC) and bone mineral density (BMD) (< 0.05) than the soccer players on the artificial turf, basketball players on parquet, and handball players on synthetic. In conclusion, a hard playing surface, with less vertical deformation and force reduction, and greater energy return, is associated with higher levels of BMD and BMC in growing girls, regardless of the sport they practice.  相似文献   
34.
The aim of this study was to investigate the effects of target distance on temporal and impact force parameters that are important performance factors in taekwondo kicks. Forty-nine taekwondo athletes (age = 24.5 ± 5.9 years; mass = 79.9 ± 10.8 kg) were recruited: 13 male experts, 21 male novices, 8 female experts, and 6 female novices. Impact force, reaction time, and execution time were computed. Three-way repeated measure ANOVAs revealed significant ‘distance’ effect on impact force, reaction time, and execution time (p = 0.001). Comparisons between distance conditions revealed that taekwondo athletes kicked with higher impact force from short distance (17.6 ± 7.5 N/kg) than from long distance (13.1 ± 5.7 N/kg) (p < 0.001), had lower reaction time from short distance (498 ± 90 ms) and normal distance (521 ± 111 ms) than from long distance (602 ± 121 ms) (p < 0.001), and had lower execution time from short distance (261 ± 69 ms/m) than from normal distance (306 ± 105 ms/m) or from long distance (350 ± 106 ms/m) (p = 0.003 and p < 0.001, respectively). In conclusion, target distance affected the kick performance; as distance increases, impact force decreased and reaction time increased. Therefore, when reaction to a simple visual stimulus is needed, kicking from a long distance is not recommended, as longer time is required to respond.  相似文献   
35.
Abstract

The Chinese martial arts (Kung Fu) have existed for centuries and are generally accepted as being beneficial for health without much empirical data. The aim of this systematic review was to assess the health effects of “hard” Kung Fu styles by performing electronic and manual searches of the literature. The aspects of health and the Kung Fu style examined varied between most studies; in some cases, the martial art group consisted of practitioners of other martial art styles also. Of 2103 references identified, only nine papers were eligible and reviewed. All were observational studies, observing a range of health aspects possibly related to Kung Fu training or performance. Our findings suggest that there is no evidence that Kung Fu practice is associated with the prevention or treatment of any health condition. However, as a moderate- to high-intensity form of aerobic exercise, it may confer benefits similar to those attributed to other aerobic training modalities. However, this hypothesis remains to be tested in clinical trials. Physiological benefits (e.g., aerobic capacity and bone density) may be associated with long-term Kung Fu practice. Future research in this area should adopt experimental designs, clearly identifying eligibility criteria, testing and training protocols, and include health-related outcomes and documentation of adverse events, to advance knowledge in this field.  相似文献   
36.
Abstract

Variable practice has been shown to be an effective strategy to improve open motor skills. However, the usefulness of this procedure in closed motor skills remains controversial. The following study has the objective of analysing the effects of variability practice in the improvement of a closed skill. The skill studied has been the tennis serve. Thirty young tennis players (13 ± 1.52 years), divided in two groups, took part in this study. One group practiced in variable conditions and the other group in consistency conditions. Both groups performed 12 training sessions (60 serves/session). The variable practice group improved their accuracy significantly compared with the consistency group (F3.25 = 3.078; P = 0.035). The velocity of serve increased after training in both groups (F3.25 = 15.890; P = 0.001). The practice in variable conditions seems to be effective in improving the performance of the tennis serve.  相似文献   
37.
38.
The silent reading fluency is not an observable behaviour and, therefore, its evaluation is perceived as more challenging and less reliable than oral reading fluency. The present research is aimed to measure the silent reading speed in a sample of proficient students, assessed by an original silent reading fluency task, based on behavioural indicators of the silent reading speed. A total of 325 high school and university skilled students (age range 14–23 years) have been assessed using 3 tasks aimed to evaluate the oral reading speed (lists of words, lists of pseudowords and narrative text) and one task aimed to measure the silent reading speed. The average silent reading speed in our sample was around 12.5 syll/sec, almost double than the oral reading speed rate. The silent reading speed had an increase from 9.13 to 12.38 syll/sec from the first year of high school (ninth grade) to the fifth year of University. Conversely, the oral reading speed remained substantially unchanged for the entire academic course. Our results showed that the reading fluency in silent mode tends to increase up to the last years of University and it may be considered the most rapid and efficient reading mode. This study highlights the importance of including both silent and oral reading modes in the assessment of the older students and young adults, since silent reading is the main reading mode for proficient readers.  相似文献   
39.
This paper reports on a project aimed at identifying and exploring the development and implementation processes of teaching practices with interactive whiteboards (IWBs) in two Swedish K-6 schools. The purpose of the project was to generate results and insights of value when preparing student teachers for professional use of IWBs and to give school leaders guidelines when implementing IWBs. A range of methods were used to collect rich and varied empirical materials in this exploratory project. Judging from our data, it was obvious that the implementation process of IWBs, just like other information and communication technology initiatives, is very technology-oriented, but also dependent on attitudes. Over the course of time in the project, different strategies emerged among the teachers regarding whether and how they used the IWBs in their lectures. It also became increasingly clear during the study that there is a distinction between technical interactivity and pedagogical interactivity. Our results further suggest that training is needed when introducing these boards for future users. This training should include both technical instructions and pedagogical discussions.  相似文献   
40.
Previously we showed how we measured pedagogy and revealed its association with learning outcomes of sixth‐form college mathematics students. In this project we followed a similar approach to the study of university transition. We particularly sought to identify the students’ perceptions of the transitional experience, and measure the association with learning outcomes. We drew on longitudinal surveys of students entering different programmes in five universities. Following them into their first year or so, allowed us to track their ‘disposition to complete the course’ and their ‘disposition to study more mathematics’, inter alia. We developed and validated two ‘fit‐for‐purpose’ measures of students’ perception of their transition, one we call ‘perception of the transitional gap/jump’ and one we call ‘degree of positive feeling about the transition’. We report some statistically and educationally significant associations between these and the students’ developing dispositions, and discuss the prospects for this approach to studying transition.  相似文献   
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