PNF法在乒乓球训练热身阶段中秀用的作用分析

探讨PNF法在乒乓球训练热身阶段中运用对于降低乒乓球运动员运动损伤发生率、提高乒乓球运动员的身体素质和改善技术动作的作用。通过对河南省的196名体育专业乒乓球专选生进行分组实验研究和组间对比分析。结果表明：在乒乓球训练的热身阶段融入PNF法可以有效降低运动损伤的发生率、提高乒乓球运动员的身体素质和改善技术动作,在乒乓球训练热身阶段中融入PNF法是一种更科学合理、系统安全的热身方法。     

Movement variability in the golf swing

Traditionally, golf biomechanics has focused upon achieving consistency in swing kinematics and kinetics, whilst variability was considered to be noise and dysfunctional. There has been a growing argument that variability is an intrinsic aspect of skilled motor performance and plays a functional role. Two types of variability are described: 'strategic shot selection' and 'movement variability'. In 'strategic shot selection', the outcome remains consistent, but the swing kinematics/kinetics (resulting in the desired ball flight) are free to vary; 'movement variability' is the changes in swing kinematics and kinetics from trial to trial when the golfer attempts to hit the same shot. These changes will emerge due to constraints of the golfer's body, the environment, and the task. Biomechanical research has focused upon aspects of technique such as elite versus non-elite kinematics, kinetics, kinematic sequencing, peak angular velocities of body segments, wrist function, ground reaction forces, and electromyography, mainly in the search for greater distance and clubhead velocity. To date very little is known about the impact of variability on this complex motor skill, and it has yet to be fully researched to determine where the trade-off between functional and detrimental variability lies when in pursuit of enhanced performance outcomes.     

The influence of social interaction on meaning construction in a virtual community

As proposed by social constructive theorists, meaningful learning and individual development were achieved through social interaction. To foster social interaction among students, this study formed an online learning community in which they played multiple roles as writers, editors and commentators. In playing different roles, they read peers' texts, edited peers' errors, evaluated peer editors' corrections and finally reconstructed their own texts. Results of this study showed that the multiple roles they played allowed them to have opportunities to view their own texts from others' perspectives. Based on these perspectives, they were more willing to acquire information from and contribute information to peers. All of this extensive information acquisition and contribution resulted in meaning construction of texts as active students improved their final drafts in both local revision (grammatical correction) and global revision (the style, organisation and development of a text) after receiving and evaluating feedback from peer editors. Their final drafts were very different from those of passive students whose first and final drafts were almost the same despite some grammatical revisions. This study suggests that, rather than relying only on an examination of students' final drafts, there may be benefits in teachers encouraging students to actively participate in social interaction by reading peers' texts, editing peers' errors and evaluating peer editors' corrections during text revisions.     

The impact of individual differences on e‐learning system satisfaction: A contingency approach

This study investigated the impact of contingent variables on the relationship between four predictors and students' satisfaction with e‐learning. Five hundred and twenty‐two university students from 10 intact classes engaging in online instruction were asked to answer questionnaires about their learning styles, perceptions of the quality of the proposed predictors and satisfaction with e‐learning systems. The results of analysis of variance and structural equation modelling analyses showed that two contingent variables, gender and job status, significantly influenced the perceptions of predictors and students' satisfaction with the e‐learning system. This study also found a statistically significant moderating effect of two contingent variables, student job status and learning styles, on the relationship between predictors and e‐learning system satisfaction. The results suggest that a serious consideration of contingent variables is crucial for improving e‐learning system satisfaction. The implications of these results for the management of e‐learning systems are discussed.     

Who matters to universities? A stakeholder perspective on humanities, arts and social sciences valorisation

Valorisation is at the centre of many debates on the future of academic research. But valorisation has largely become narrowly understood in terms of universities’ economic contributions through patenting, licensing, spin-off formation and technology transfer. This emergent restrictive definition of universities’ societal impacts is a worrying development, overlooking the potential of universities’ knowledge in the Humanities, Arts and Social Sciences (HASS). Our hypothesis is that HASS disciplines’ disadvantage compared to the hard sciences (lesser policy attention and funding for commercialisation) arises because HASS stakeholders are not sufficiently salient as stakeholders to universities. Using case studies of three policy experiments, we argue that universities’ responsiveness to stakeholders does not evolve simply and functionally but in response to the networks of relationships in which they are situated. This has important implications for how stakeholder research is used in higher education research, and for the design and implementation of policies to improve universities’ societal contributions.     

Stability and correlates of student evaluations of teaching at a Chinese university

This paper examines the stability and validity of a student evaluations of teaching (SET) instrument used by the administration at a university in the PR China. The SET scores for two semesters of courses taught by 435 teachers were collected. Total 388 teachers (170 males and 218 females) were also invited to fill out the 60‐item NEO Five‐Factor Inventory together with a demographic information questionnaire. The SET responses were found to have very high internal consistency and confirmatory factor analysis supported a one‐factor solution. The SET re‐test correlations were .62 for both the teachers who taught the same course (n = 234) and those who taught a different course in the second semester (n = 201). Linguistics teachers received higher SET scores than either social science or humanities or science and technology teachers. Student ratings were significantly related to Neuroticism and Extraversion. Regression results showed that the Big‐Five personality traits as a group explained only 2.6% of the total variance of student ratings and academic discipline explained 12.7% of the total variance of student ratings. Overall the stability and validity of SET was supported and future uses of SET scores in the PR China are discussed.     

Connecting high school physics experiences,outcome expectations,physics identity,and physics career choice: A gender study

This study explores how students' physics identities are shaped by their experiences in high school physics classes and by their career outcome expectations. The theoretical framework focuses on physics identity and includes the dimensions of student performance, competence, recognition by others, and interest. Drawing data from the Persistence Research in Science and Engineering (PRiSE) project, which surveyed college English students nationally about their backgrounds, high school science experiences, and science attitudes, the study uses multiple regression to examine the responses of 3,829 students from 34 randomly selected US colleges/universities. Confirming the salience of the identity dimension for young persons' occupational plans, the measure for students' physics identity used in this study was found to strongly predict their intended choice of a physics career. Physics identity, in turn, was found to correlate positively with a desire for an intrinsically fulfilling career and negatively with a desire for personal/family time and opportunities to work with others. Physics identity was also positively predicted by several high school physics characteristics/experiences such as a focus on conceptual understanding, real‐world/contextual connections, students answering questions or making comments, students teaching classmates, and having an encouraging teacher. Even though equally beneficial for both genders, females reported experiencing a conceptual focus and real‐world/contextual connections less frequently. The explicit discussion of under‐representation of women in science was positively related to physics identity for female students but had no impact for male students. Surprisingly, several experiences that were hypothesized to be important for females' physics identity were found to be non‐significant including having female scientist guest speakers, discussion of women scientists' work, and the frequency of group work. This study exemplifies a useful theoretical framework based on identity, which can be employed to further examine persistence in science, and illustrates possible avenues for change in high school physics teaching. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 978–1003, 2010     

Bridging scientific reasoning and conceptual change through adaptive web‐based learning

This study reports an adaptive digital learning project, Scientific Concept Construction and Reconstruction (SCCR), and examines its effects on 108 8th grade students' scientific reasoning and conceptual change through mixed methods. A one‐group pre‐, post‐, and retention quasi‐experimental design was used in the study. All students received tests for Atomic Achievement, Scientific Reasoning, and Atomic Dependent Reasoning before, 1 week after, and 8 weeks after learning. A total of 18 students, six from each class, were each interviewed for 1 hour before, immediately after, and 2 months after learning. A flow map was used to provide a sequential representation of the flow of students' scientific narrative elicited from the interviews, and to further analyze the level of scientific reasoning and conceptual change. Results show students' concepts of atoms, scientific reasoning, and conceptual change made progress, which is consistent with the interviewing results regarding the level of scientific reasoning and quantity of conceptual change. This study demonstrated that students' conceptual change and scientific reasoning could be improved through the SCCR learning project. Moreover, regression results indicated students' scientific reasoning contributed more to their conceptual change than to the concepts students held immediately after learning. It implies that scientific reasoning was pivotal for conceptual change and prompted students to make associations among new mental sets and existing hierarchical structure‐based memory. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47: 91–119, 2010     

Four case studies,six years later: Developing system thinking skills in junior high school and sustaining them over time

This study examines the process by which system thinking perceptions develop within the context of a water cycle curriculum. Four junior high school students undergoing an especially designed inquiry‐based intervention were closely observed before, during, immediately after, and 6 years after completing a year long systems‐based learning program. The employed research tools included observations, semi‐structured interviews, and a number of “concept viewing” tools (drawings, concept maps, and repertory grids). Out of the data, four distinct “stories,” each presenting a different way of constructing hydro system mental models, are described. The paper's main conclusion is that students develop their systems mental models and remember the learned material based on learning patterns that tend to remain unchanged over time. Consequently, in order to facilitate efficient and lasting construction of students' system models, learning experiences should harness these, and especially the meta‐cognitive learning pattern, which holds special significance for constructing systems. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 1253–1280, 2010