An analysis of the relationship between the linear hammer speed and the thrower applied forces during the hammer throw for male and female throwers

The purpose of this study was to investigate the relationship between the cable force and linear hammer speed in the hammer throw and to identify how the magnitude and direction of the cable force affects the fluctuations in linear hammer speed. Five male (height: 1.88 +/- 0.06 m; body mass: 106.23 +/- 4.83 kg) and five female (height: 1.69 +/- 0.05 m; body mass: 101.60 +/- 20.92 kg) throwers participated and were required to perform 10 throws each. The hammer's linear velocity and the cable force and its tangential component were calculated via hammer head positional data. As expected, a strong correlation was observed between decreases in the linear hammer speed and decreases in the cable force (normalised for hammer weight). A strong correlation was also found to exist between the angle by which the cable force lags the radius of rotation at its maximum (when tangential force is at its most negative) and the size of the decreases in hammer speed. These findings indicate that the most effective way to minimise the effect of the negative tangential force is to reduce the size of the lag angle.     

Understanding Biological Evolution Through Computational Thinking

Science & Education - Computational thinking is a contemporary science and engineering practice that has been introduced to the US science classrooms due to its emphasis in the Next Generation...     

The Emotionally Affected University Student: support from the university community

The study measured the general attitudes towards disability of academics, administrative staff, and students in a small rural University. Respondents were also asked to comment on the nature of support that might be provided for a student with an emotional disability. There were some significant differences in level and nature of support for students with an emotional disability among academics, administrative staff, and students. These differences were related to the levels of comfort with, and sympathy felt towards, students with an emotional disability. However, overall the results suggest that university students with expressed emotional difficulties are liable to be relatively negatively regarded and are not liable to receive much concrete assistance for the difficulties they face. It is proposed that the data supports the notion that academics, of all the groups measured, are best placed to decide types of support for students with an emotional disability on a case by case basis.     

Change in throwing pattern: critical values for control parameter of velocity

The purpose of this study was to determine the critical values at which throwing patterns change when scaling up on the control parameter of velocity. Thirty-six participants (ages: 6-12 years) were categorized into four throwing levels according to patterns represented by temporal joint lag. Each participant was required to complete 5 overhand throws at each of 10 relative velocities for a total of 50 trials per participant. The lowest velocity was 10% of maximum, with increases in increments of 10% up to a maximum effort. Quantitative and qualitative analyses indicated that critical values varied according to throwing category and joint. Generally, lower skilled throwers (Levels 1 and 2) had less stable joint lag and changed patterns at lower velocities than higher skilled (Levels 3 and 4) throwers.     

Changes in limb striking pattern: effects of speed and accuracy

This study investigated the changes in an arm striking pattern as a result of practice and the effects of speed and accuracy requirements on such changes. The task was to strike a baseball-size foam ball from a batting tee adjusted to the height of each subject's iliac crest. Ten righthanded subjects, initially displaying an inefficient striking pattern, volunteered for this study. All subjects performed the task according to the following conditions: (1) speed, (2) accuracy, and (3) speed and accuracy. Each subject completed 10 trials in each condition (randomly ordered) for five consecutive days. A high-speed camera (64 fps) was used to photograph subjects' striking patterns for each condition over the 5-day period. Analysis of variance of joint angles at arm reversal and contact and velocity of hand relative to the glenohumeral axis at contact revealed that subjects initially constrained limb segments to act in a unitary fashion; then, with practice, a more efficient pattern was developed. The requirement of speed was found to enhance a change in limb configuration, whereas the requirement of accuracy, and subsequent reduction in speed, impeded the development of a more efficient striking pattern. Analysis of radial error revealed no differences in accuracies to the target by either condition or day of practice. A graphic analysis of segmental angular momentum versus relative time showed that joint angle changes allowed subjects to transfer angular momentum and thereby increase the velocity of the hand at contact.     

The Credential Question: Attitudes of Teaching Artists in Dance and Theatre Arts

How do teaching artists perceive the need and usefulness of a credential program specifically designed for teaching artists in dance and theatre arts?     

Distributed leadership with the aim of ‘reculturing’: a departmental case study

This article considers a secondary science department that has, since 2000, developed distributed leadership as a form of human capacity building. Using a longitudinal ethnographic case study allowed us to consider how distributed leadership can be nurtured and developed in a department. Our analysis centres on two key issues: the nature and pattern of distributed leadership practices and the continuity that provides coherence to those practices. From our analysis, there appear to be two major conclusions. The first of these is the need for administrators to be purposeful in the appointments that they make to formal leadership positions. To enact distributed leadership practices requires leaders who can exercise both formal power and influence. The second conclusion relates to the time required for continuity of leadership practices to give rise to changes that lead to teachers managing the teaching and learning programme.