The kinematic differences between off-spin and leg-spin bowling in cricket

Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.     

Effects of load mass carried in a backpack upon respiratory muscle fatigue

Purpose: The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20?kg, causes respiratory muscle fatigue. Methods: Eight males performed four randomised load carriage (LC) trials comprising 60?min walking at 6.5?km?h^?1 wearing a backpack of either 0 (LC₀), 10 (LC₁₀), 15 (LC₁₅) or 20?kg (LC₂₀). Inspiratory (P_Imax) and expiratory (P_Emax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60?s of each trial. Results: Group mean P_Imax and P_Emax were unchanged following 60-min load carriage in all conditions (p?>?.05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p?p?>?.05). Conclusions: These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20?kg in a backpack for up to 60?min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters.     

Education and social cohesion: developing a framework for education sector reform in Sri Lanka1

There is increasing interest in understanding and describing the links between education and ‘social cohesion’. However, the theoretical and empirical base for understanding these links is limited. There is also a shortage of practical tools for education policy‐makers and planners, to help them assess the impact of policies and investments, and to plan for future reform. This paper describes the initial development of an analytical and planning framework for addressing education and social cohesion within the context of a sector‐wide approach to education reform in Sri Lanka. A brief literature review suggests three inter‐connected domains in which links between education and social cohesion might be usefully analysed, together with three working hypotheses: (i) political economy/governance: education affects social cohesion through transparency and participation in education policy formulation, planning and management; (ii) equity/equality of opportunity: education affects social cohesion through the distribution of education resources, opportunities and outcomes; (iii) teaching/learning: education affects social cohesion through the development of certain competencies in students. Drawing on this analytical framework, research conducted in Sri Lanka is used to identify a set of interventions to promote social cohesion, with corresponding baseline, process and outcome indicators as benchmarks for measuring the progress and impact of intended policy measures. This process is described within the context of a ‘sector‐wide approach’ to education reform, intended to bring together the activities of the government and external partners within a single comprehensive medium‐term planning and budgetary framework.     

Mathematical Modeling in the Primary School: Children's Construction of a Consumer Guide

This paper examines 6th grade children's local conceptual development and mathematization processes as they worked a comprehensive mathematical modeling problem (creating a consumer guide for deciding the best snack chip) over several class periods. The children and their teachers were participating in a 3-year longitudinal teaching experiment in which sequences of mathematical modeling problems were implemented from the 5th grade (10 years of age) though to the 7th grade. In contrast to traditional problem solving, mathematical modeling requires children to generate and develop their own mathematical ideas and processes, and to form systems of relationships that are generalizable and reusable. Reported here is a detailed analysis of the iterative cycles of development of one group of children as they worked the problem, followed by a summary of the mathematization processes displayed by all groups. Children's critical reflections on their models are also reported. The results show how children can independently develop constructs and processes through meaningful problem solving. Children's development included creating systems for operationally defining constructs; selecting, categorizing, and ranking factors; quantifying quantitative and qualitative data; and transforming quantities.     

The study of butterflies

In this part of the series on butterflies, we look at the types of variations found within species as well as their causes.     

Students with special educational needs within PISA

Abstract

Since 2003, the Programme for International Student Assessment (PISA) has included students with special educational needs (SEN), identified as those with functional disabilities, those with cognitive/behavioural/emotional disabilities and those with limited test language proficiency. While the number of countries and included students has increased with each test administration, the percentage of students with SEN remains extremely low. The inclusion of these students is not an intentional PISA design parameter but rather a response to the interaction between the need to maintain strict sampling criteria and country-level educational mandates to include SEN students in standardised testing. Based on the analysis of student participation and performance across four cycles of PISA (2003–2012), this paper examines the challenges that exist in current PISA procedures related to: student sampling, eligibility and identification; assessment methodology; and reporting results. PISA practices, their limitations for scientific inferences and recommendations for design improvements are given.