A comparison of muscle activity and 1-RM strength of three chest-press exercises with different stability requirements

Abstract

The purpose of this study was to compare one-repetition maximum (1-RM) and muscle activity in three chest-press exercises with different stability requirements (Smith machine, barbell, and dumbbells). Twelve healthy, resistance-trained males (age 22.7 ± 1.7 years, body mass 78.6 ± 7.6 kg, stature 1.80 ± 0.06 m) were tested for 1-RM of the three chest-press exercises in counterbalanced order with 3–5 days of rest between the exercises. One-repetition maximum and electromyographic activity of the pectoralis major, deltoid anterior, biceps, and triceps brachii were recorded in the exercises. The dumbbell load was 14% less than that for the Smith machine (P ≤ 0.001, effect size [ES] = 1.05) and 17% less than that for the barbell (P ≤ 0.001, ES = 1.11). The barbell load was ～3% higher than that for the Smith machine (P = 0.016, ES = 0.18). Electrical activity in the pectoralis major and anterior deltoid did not differ during the lifts. Electrical activity in the biceps brachii increased with stability requirements (i.e. Smith machine <barbell <dumbbells; P ≤ 0.005; ES = 0.57, 1.46, and 2.00, respectively), while triceps brachii activity was reduced using dumbbells versus barbell (P = 0.007, ES = 0.73) and dumbbells versus Smith machine (P = 0.003, ES = 0.62). In conclusion, high stability requirements in the chest press (dumbbells) result in similar (pectoralis major and anterior deltoid), lower (triceps brachii) or higher (biceps brachii) muscle activity. These findings have implications for athletic training and rehabilitation.     

青少年跳高赛前控制训练的实验研究

为了探讨跳高赛前控制训练这一课题，我们运用运动训练学的基本原理，采用随训跟踪的方法．对其进行了实验探讨，旨在摸索跳高赛前控制训练的一般规律，为青少年跳高的科学化训练积累经验。     

试论高职学院体育师资队伍建设

随着社会和高等教育形势的快速发展，高等职业技术教育成为高等教育的一部分，已成为当前社会关注的一个热点。高职学院要能适应高等教育的要求，适应新的办学模式，全面提高教学质量和办学水平，关键是拥有一支与人才培养目标相一致的数量、质量合格的教师队伍。而目前高职学院体育师资队伍的现状，与高等教育的要求及全面推进学校体育工作深化改革的目标，尚存有较大的差距。因此要针对现状，在加强教师政治思想、德育教育，优化教师知识结构，优化师资队伍结构，提高教学科研能力、水平等几个主要方面，采取积极有效的措施；加强队伍建设，全面提高体育教师的整体素质水平，尽快适应高等教育发展的需要及高校体育教学改革、科学研究的要求。     

Learning to mark: exemplars,dialogue and participation in assessment communities

The problems of shifting from norm-referenced assessment to criterion-referenced assessment have been identified by several scholars in recent years. These important critiques touch on a number of areas, but neglect a key question about how assessors learn to accomplish what Shay calls a ‘socially situated interpretive act'. Research that does exist tends to focus on salaried, full-time academics. This overlooks the heterogeneity of the academic labour force in higher education and the substantial contribution made by contract (hourly-paid) lecturers, particularly in applied disciplines such as Business and Management. This study explores how nine newcomers to a UK Business School – including salaried and contract staff – attempt to understand local assessment practice. We use a situated learning lens to analyse their diary entries and interviews about their experiences of learning to mark. Drawing on scholars such as Sadler, we examine the suggestion that exemplars are important for newcomers coming to understand local assessment practice. We argue for the fundamental importance of dialogue about exemplars and other aspects of practice, both to develop inter-subject understandings of assessment ‘anchor points' and also to foster among newcomers (and especially contract lecturers) a greater sense of participating in, and being valued by, the local assessment community.     

Retrieving and classifying instances of source code plagiarism

Automatic detection of source code plagiarism is an important research field for both the commercial software industry and within the research community. Existing methods of plagiarism detection primarily involve exhaustive pairwise document comparison, which does not scale well for large software collections. To achieve scalability, we approach the problem from an information retrieval (IR) perspective. We retrieve a ranked list of candidate documents in response to a pseudo-query representation constructed from each source code document in the collection. The challenge in source code document retrieval is that the standard bag-of-words (BoW) representation model for such documents is likely to result in many false positives being retrieved, because of the use of identical programming language specific constructs and keywords. To address this problem, we make use of an abstract syntax tree (AST) representation of the source code documents. While the IR approach is efficient, it is essentially unsupervised in nature. To further improve its effectiveness, we apply a supervised classifier (pre-trained with features extracted from sample plagiarized source code pairs) on the top ranked retrieved documents. We report experiments on the SOCO-2014 dataset comprising 12K Java source files with almost 1M lines of code. Our experiments confirm that the AST based approach produces significantly better retrieval effectiveness than a standard BoW representation, i.e., the AST based approach is able to identify a higher number of plagiarized source code documents at top ranks in response to a query source code document. The supervised classifier, trained on features extracted from sample plagiarized source code pairs, is shown to effectively filter and thus further improve the ranked list of retrieved candidate plagiarized documents.     

The Impact of Institutional Context,Education and Labour Market Policies on Early School Leaving: a comparative analysis of EU countries

This article presents a comparative analysis of the determinants of early school leaving (ESL) at the country level. We decompose ESL rates into two components: a ‘primary’ rate reflecting unqualified school leaving from initial education, and a second component accounting for early school leavers who participate in training programmes. Both may be influenced by structural and policy determinants. We examine how the ESL rate is affected by macro-economic and social context variables such as GDP/capita, growth, poverty, and youth unemployment, as well as system characteristics of the education system (such as legal school leaving age, grade retention, early tracking, and size of vocational education) and the labour market and social protection systems (minimum wages, unemployment insurance).     

Beginning and end of the internship: student teachers’ interpersonal profiles and the accuracy of their self-beliefs

An important purpose of internships in teacher preparation programmes is to develop competence through experience. The research questions in the present study concern student teachers’ interpersonal profiles (i.e. patterns of their interpersonal behaviour as perceived by students) and the accuracy of their self-belief regarding the interpersonal relationship with students at the beginning and end of the internship. Participants were student teachers (n=34) of a one-year teacher education programme. There were fewer student teachers with preferable interpersonal profiles at the end of the internship than in the beginning. Self-beliefs at the beginning indicated that the majority of student teachers were underestimating themselves; at the end of the internship most of them were overestimating themselves. About two-thirds had more accurate self-beliefs at the end of the internship than at the beginning. Overestimating oneself seemed negatively related to more accurate self-beliefs at the end of the internship and student teachers with more preferable profiles had more accurate self-beliefs.     

Developing Service Area Indices for Community Colleges: California's Method and Experience

The economic, educational and social environments of the students served by a community college are important factors in college performance accountability, policy analysis, program evaluation, and strategic planning. For example, previous research shows that income per county is a significant predictor of transfer rates for community colleges. However, conditions for the actual geographic area of the students served by a community college may differ, for various reasons, from the economic conditions for the county in which the college is located. This article describes the development of institutional or college-level indices as an enhancement to county-level data, their use as adjustment variables for California's Accountability Reporting for the Community Colleges (ARCC), and their applicability to other research and planning studies. The service area indices are created by combining the enrollment patterns of students by ZIP Code of residence with ZCTA (ZIP Code Tabulation Area) level economic and educational data from Census 2000.     

Data Mining to Combat Terrorism and the Roots of Privacy Concerns

Recently, there has been a heavy debate in the US about the government’s use of data mining in its fight against terrorism. Privacy concerns in fact led the Congress to terminate the funding of TIA, a program for advanced information technology to be used in the combat of terrorism. The arguments put forward in this debate, more specifically those found in the main report and minority report by the TAPAC established by the Secretary of Defense to examine the TIA issue, will be analysed to trace the deeper roots of this controversy. This analysis will in turn be used as a test case to examine the adequacy of the usual theoretical frameworks for these kinds of issues, in particular the notion of privacy. Whereas the dominant theoretical framing of the notion of privacy turns around access to information, most of the core arguments in the debate do not fit in this kind of framework. The basic disagreements in the controversy are not about mere access, they involve both access and use. Furthermore, whereas the issue of access by itself refers to a more or less static situation, the real disagreements much more concern the organisational dynamics of the use of information, the mechanisms in the organisation that control these dynamics, and the awareness present within the organisation of the ‘social risks’ these dynamics represent. The bottom line question is whether the assessment of these gives sufficient reason for trust.