Optimising the front foot contact phase of the cricket fast bowling action

ABSTRACT

Cricket fast bowling is a dynamic activity in which a bowler runs up and repeatedly delivers the ball at high speeds. Experimental studies have previously linked ball release speed and several technique parameters with conflicting results. As a result, computer simulation models are increasingly being used to understand the effects of technique on performance. This study evaluates a planar 16-segment whole-body torque-driven simulation model of the front foot contact phase of fast bowling by comparing simulation output with the actual performance of an elite fast bowler. The model was customised to the bowler by determining subject-specific inertia and torque parameters. Good agreement was found between actual and simulated performances with a 4.0% RMS difference. Varying the activation timings of the torque generators resulted in an optimised simulation with a ball release speed 3.5 m/s faster than the evaluation simulation. The optimised technique used more extended front ankle and knee joint angles, increased trunk flexion and a longer delay in the onset of arm circumduction. These simulations suggest the model provides a realistic representation of the front foot contact phase of fast bowling and is suitable to investigate the limitations of kinematic or kinetic variables on fast bowling performance.     

“Good” organisational reasons for “ineffectual” research: Evaluating summative evaluation of museums and galleries

New displays, galleries and exhibitions in museums and galleries are increasingly subject to summative evaluations, wide-ranging investigations that examine how visitors respond to and engage with particular initiatives. These evaluations provide insights into the behaviour and attitudes of visitors and the ways in which particular exhibitions, exhibits and information resources facilitate engagement, participation and learning. Unfortunately, however, summative evaluation has relatively little impact either on the particular initiative or more generally in contributing to our knowledge of visitor behaviour and understanding of best practice. In this paper, we suggest that the relative lack of impact of summative evaluation is not primarily due to any methodological shortcomings or the idiosyncrasies of some of the approaches that are used. Rather, the organisational and institutional context in which summative evaluation is commissioned, undertaken and received can impose contradictory demands and undermine the opportunity of learning from and applying the findings of evaluation.     

Internationalisation and distance education: a Hong Kong case study

The accelerating globalisation of world economic relations has been paralleled by a progressive internationalisation of higher education, including the use of distance education. But the modification of distance education materials and the provision of local tutorial support are only rarely undertaken, despite the fact that in social science and the humanities such materials are culturally saturated. This Hong Kong case study in teacher education examines the issues, describes the opportunities and difficulties involved, and argues that cultural adaptation merits a higher priority than at present.     

Consistency of performances in the Tkatchev release and re-grasp on high bar

The Tkatchev on the high bar is a release and re-grasp skill in which the gymnast rotates in a direction during flight opposite to that of the preceding swing. Since the release window is defined as the time during which the gymnast has appropriate linear and angular momentum to ensure the bar can be re-grasped, it was speculated that the release windows for this skill would be smaller than for dismounts that are less constrained. One senior male gymnast competing at national standard performed 60 Tkatchev trials. A four-segment planar simulation model of the gymnast and high bar was used to determine the release windows in 10 successful and 10 unsuccessful performances of the Tkatchev recorded using a Vicon motion analysis system. Model parameters were optimized to obtain a close match between simulations and recorded performances in terms of rotation angle (1 degree), bar displacements (0.01 m), and release velocities (1%). Each matched simulation was used to determine the time window around the actual point of release for which the model had appropriate release parameters to complete the Tkatchev successfully. The release windows for the successful trials were small compared with those of dismounts. The unsuccessful trials were associated with later release and later timing of the actions at the shoulders and hips.     

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Institut national d'Etude du travail et d'Orientation professionnelle

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UNESCO     

CASE Tools: Constructivism and its Application to Learning and Usability of Software Engineering Tools

Software Engineering is a new discipline aimed at the improvement of the production of large, quality software systems. Interest in CASE tools has grown because of the important role they play in supporting the software development process. Studies show these complex and sophisticated tools have a positive impact on quality and productivity but they have been slow to be adopted by industry; this is partially explained by the difficulty of learning to use the tool.     

Do we need norms of fitness for children with autistic spectrum condition?

The increasingly sedentary habits of children, and rising obesity levels, are prompting concern for children's future health. Children with autistic spectrum condition (ASC) show a clear trend in this regard. Within school, an understanding of how an individual's fitness compares to age norms is important in order to design appropriate exercise programmes. This study, by Maurice Place, Kathleen Dickinson and Joanna Reynolds, all based at Northumbria University, assessed 100 children with ASC and learning difficulty, and found a wide variation in fitness levels as measured by the Eurofit tests. In addition the measure of cardio‐pulmonary fitness (VO_{2 max}) was generally poor. In boys, body mass index (BMI) showed only a modest correlation with this measure of cardio‐pulmonary fitness, with the results for the girls not being significant. Using a variant of the established BMI calculation did not improve the correlation. To our knowledge this article offers the first set of published Eurofit test results for children with ASC and highlights the generally poor level of cardio‐pulmonary fitness in this group of children.