The energetics and benefit of an arm swing in submaximal and maximal vertical jump performance

Abstract

The aims of this study were to investigate the energy build-up and dissipation mechanisms associated with using an arm swing in submaximal and maximal vertical jumping and to establish the energy benefit of this arm swing. Twenty adult males were asked to perform a series of submaximal and maximal vertical jumps while using an arm swing. Force, motion and electromyographic data were recorded during each performance and used to compute a range of kinematic and kinetic variables, including ankle, knee, hip, shoulder and elbow joint powers and work done. It was found that the energy benefit of using an arm swing appears to be closely related to the maximum kinetic energy of the arms during their downswing, and increases as jump height increases. As jump height increases, energy in the arms is built up by a greater range of motion at the shoulder and greater effort of the shoulder and elbow muscles but, as jump height approaches maximum, these sources are supplemented by energy supplied by the trunk due to its earlier extension in the movement. The kinetic energy developed by the arms is used to increase their potential energy at take-off but also to store and return energy from the lower limbs and to “pull” on the rest of the body. These latter two mechanisms become more important as jump height increases with the pull being the more important of the two. We conclude that an arm swing contributes to jump performance in submaximal as well as maximal jumping but the energy generation and dissipation sources change as performance approaches maximum.     

The influence of` preseason training phase and training load on body composition and its relationship with physical qualities in professional junior rugby league players

ABSTRACT

This study investigated changes in body composition in relation to training load determined using RPE and duration (sRPE), and its relationship with physical qualities over a preseason period. Sixteen professional academy players (age = 17.2 ± 0.7 years; stature = 179.9 ± 4.9 cm; body mass = 88.5 ± 10.1 kg) participated in the study. Body composition was assessed before and after each training phase and physical qualities assessed at the start and end of preseason. Across the whole preseason period, skinfold thickness, body fat percentage and fat mass were most likely lower (ES = ?0.73 to ?1.00), and fat free mass and lean mass were likely to most likely higher (ES = 0.31 to 0.40). Results indicated that the magnitude of change appeared phase-dependent (ES = ?0.05 to ?0.85) and demonstrated large individual variability. Changes in physical qualities ranged from unclear to most likely (ES = ?0.50 to 0.64). Small to moderate correlations were observed between changes in body composition, and TL with changes in physical qualities. This study suggests training phase and TL can influence a player’s body composition; that large inter-participant variability exists; and that body composition and TL are related to the change in physical qualities.     

Learning about print: the development of orthographic processing and its relationship to word reading in first grade children in French immersion

As children learn to read, they become sensitive to the patterns that exist in the ways in which their language(s) are represented in print. This skill is known as orthographic processing. We examined the nature of orthographic processing in English and French for children in the first grade of a French immersion program, and the relationship between orthographic processing and reading beyond controls for mother’s education, non-verbal reasoning, English vocabulary and phonological awareness. We found that children showed greater orthographic processing skill to patterns that were common to both of their languages than to those that occurred in just one of their languages. Across both lexical and sub-lexical orthographic processing measures, scores were related to word reading within each language, beyond our control variables. There was some evidence of cross-language relationships between orthographic processing and word reading, both for lexical and sub-lexical language-shared measures of orthographic processing. These findings suggest that children’s attention to features that are common both languages might be one source of transfer of orthographic processing to reading between languages.     

Effectiveness of a Short,Intense Bridging Course for Scaffolding Students Commencing University-level Study of Chemistry

Bridging courses designed to support students commencing tertiary education are widespread, and some evidence for the value of semester-length courses has been reported; however, little attention has been paid to short-but-intense bridging courses, and empirical evidence of their effectiveness is particularly sparse. The current study followed the academic performance of a cohort of students enrolled in a first-year chemistry unit of study designed for those with little or no background knowledge of chemistry. The aims of this study are two-fold: first to determine the strength of the linkage between prior knowledge in chemistry and performance on the end of semester exam, and secondly, to explore the reasons for any differences observed. In particular, the value of the week-long intensive-mode bridging course offered by the University of Sydney was analysed. Quantitative and qualitative data were collected. The research has shown that participation in the chemistry bridging course is associated with ‘bridging the gap’ in academic performance between students with No Prior Chemistry background and those with a Strong Background. While the content of the bridging course is a significant contributor to academic success, so too is the confidence in their own learning that the course engenders among participants.     

Teaching and learning with technology in higher education: blended and distance education needs ‘joined-up thinking’ rather than technological determinism

In higher education (HE), some of the distinctions between conventional, campus-based universities and those dedicated to distance education are being eroded through the use of information and communication technology. Despite huge investments in technology to enhance teaching and learning, there has been a considerable lack of clarity about what this actually signifies in practice. Implementation decisions are frequently technology-led rather than being focused on clearly defined educational goals. This article attempts to examine key issues and synthesise a number of important debates relating to teaching and learning with technology in HE. It examines some of the key factors influencing how technology is utilised in HE teaching and learning. It argues that decision-making by managers and teachers with regard to technology use needs to be founded upon evidence that takes account of all of those factors, not just a narrow selection of them. Rather than just considering technical issues and/or the idealised promises made about technologies, ‘joined-up thinking’ is required to integrate the multiple contextual factors that all influence how technology is actually used in teaching and learning.     

Development and validation of an assessment of adult educators' reading instructional knowledge

The purpose of this paper is to describe briefly the development and utility of the Assessment of Reading Instructional Knowledge-Adults (ARIK-A), the only nationally normed (n?=?468) measure of adult reading instructional knowledge, created to facilitate professional development of adult educators. Developmental data reveal reliabilities ranging from 0.73 to 0.85 for five ARIK-A scales (alphabetics, fluency, vocabulary, comprehension, and assessment) and 0.91 for the composite score; factor analytic data and expert review provide support for construct validity as well. Information on how to use the ARIK-A to determine mastery and relative standing is presented. With two alternate forms, the ARIK-A is a promising and needed tool for adult education practitioners within continuing education and professional development contexts.     

Chlorella vulgaris triggers apoptosis in hepatocarcinogenesis-induced rats

Chlorella vulgaris (CV) has been reported to have antioxidant and anticancer properties. We evaluated the effect of CV on apoptotic regulator protein expression in liver cancer-induced rats. Male Wistar rats (200∼250 g) were divided into eight groups: control group (normal diet), CDE group (choline deficient diet supplemented with ethionine in drinking water to induce hepatocarcinogenesis), CV groups with three different doses of CV (50, 150, and 300 mg/kg body weight), and CDE groups treated with different doses of CV (50, 150, and 300 mg/kg body weight). Rats were sacrificed at various weeks and liver tissues were embedded in paraffin blocks for immunohistochemistry studies. CV, at increasing doses, decreased the expression of anti-apoptotic protein, Bcl-2, but increased the expression of pro-apoptotic protein, caspase 8, in CDE rats, which was correlated with decreased hepatoctyes proliferation and increased apoptosis as determined by bromodeoxy-uridine (BrdU) labeling and terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assay, respectively. Our study shows that CV has definite chemopreventive effect by inducing apoptosis via decreasing the expression of Bcl-2 and increasing the expression of caspase 8 in hepatocarcinogenesis-induced rats. Project supported by Department of Biochemistry, Faculty of Medicine, UKM Medical Center, Universiti Kebangsaan Malaysia, and the Malaysian Ministry of Science and Technological Innovation (MOSTI)     

Judges' Use of Examinee Performance Data in an Angoff Standard‐Setting Exercise for a Medical Licensing Examination: An Experimental Study

Although the Angoff procedure is among the most widely used standard setting procedures for tests comprising multiple‐choice items, research has shown that subject matter experts have considerable difficulty accurately making the required judgments in the absence of examinee performance data. Some authors have viewed the need to provide performance data as a fatal flaw for the procedure; others have considered it appropriate for experts to integrate performance data into their judgments but have been concerned that experts may rely too heavily on the data. There have, however, been relatively few studies examining how experts use the data. This article reports on two studies that examine how experts modify their judgments after reviewing data. In both studies, data for some items were accurate and data for other items had been manipulated. Judges in both studies substantially modified their judgments whether the data were accurate or not.     

Predicting grade point average from the hybrid model of learning in personality: consistent findings from Ugandan and Australian students

Jackson developed a hybrid model of learning in personality, known as the Learning Styles Profiler (LSP), which seeks to explain personality in terms of biological, socio‐cognitive and experiential processes. The hybrid model argues that functional learning outcomes can be understood in terms of how cognitions and experiences re‐express sensation seeking as functional learning. In two studies from Uganda and Australia (n = 136 and n = 290 respectively), grade point average (GPA) of students was successfully predicted from the hybrid model. Results show evidence of three indirect pathways from sensation seeking through cognitions to GPA and provide a new understanding of the way in which personality can predict performance.     

Conditional inference and advanced mathematical study: further evidence

In this paper, we examine the support given for the ‘theory of formal discipline’ by Inglis and Simpson (Educational Studies Mathematics 67:187–204, 2008). This theory, which is widely accepted by mathematicians and curriculum bodies, suggests that the study of advanced mathematics develops general thinking skills and, in particular, conditional reasoning skills. We further examine the idea that the differences between the conditional reasoning behaviour of mathematics and arts undergraduates reported by Inglis and Simpson may be put down to different levels of general intelligence in the two groups. The studies reported in this paper call into question this suggestion, but they also cast doubt on a straightforward version of the theory of formal discipline itself (at least with respect to university study). The paper concludes by suggesting that either a pre-university formal discipline effect or a filtering effect on ‘thinking dispositions’ may give a better account for the findings.