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.     

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.     

Reproducibility of measurement techniques used for creatine kinase,interleukin-6 and high-sensitivity C-reactive protein determination over a 48 h period in males and females

To examine the reproducibility of three measurement techniques used to determine creatine kinase, interleukin-6 and high-sensitivity C-reactive protein, 50 participants had blood samples taken on two occasions. Fingertip plasma samples were analysed using the Reflotron for CK determination. Venous blood samples collected into serum separator tubes were used for IL-6 and hs-CRP analyses. IL-6 was measured using an enzyme linked immune assay development kit. The hs-CRP was measured by an in-house ELISA method. Dependent t-tests showed no systematic bias between samples. The interdian CV was 20.0% for CK, 15.3% for IL-6 and 44.2% for hs-CRP. The intraclass correlation coefficient was 0.90 for CK, 0.98 for IL-6 and 0.70 for hs-CRP. The 95% limits of agreement were ?69.7 to 63.5 IU/L for CK, ?1.48 to 1.80 pg/ml for IL-6 and ?1.10 to 0.91 µg/L for hs-CRP. The results demonstrate low absolute reproducibility, which may obscure a true experimental effect.     

From order to chaos: The impact of educational telecommunications on post-secondary education

The convergence of digital communications technologies is changing the nature of the relationships between post-secondary institutions, their students, and the private sector. The current predictable and ordered world of inter-institutional relationships is breaking down, to be replaced by one of perpetual change. Contemporary relationships can be modeled using Christaller's central place theory. On the other hand, we must turn to chaos theory for clues as to how institutions will be operating in an environment characterised by complexity and constant flux.