Power output in traditional and ballistic bench press in elite athletes: Influence of training background

This study aimed to compare the power production in traditional bench-press (TBP) and ballistic bench-throw (BBT) exercises. Furthermore, we assessed the differences in velocity, force, and power outputs between TBP and BBT. Finally, we tested the differences between the loads used to optimize power (optimum power load; OPL) in both exercises, using three distinct power-variables: mean power (MP), mean propulsive power (MPP), and peak power (PP). Sixty athletes from different sports were divided into two groups, according to their training characteristics: hypertrophy-based trained athletes (HTA), thirty-one athletes performing hypertrophy training programmes for (at least) 12-weeks; and power-based trained athletes (PTA), twenty-nine athletes performing power-oriented training sessions for (at least) 12-weeks. Magnitude-based inferences were used to test for differences between groups. Independent of the variable analyzed (MP, MPP, or PP), the PTA produced greater power values in BBT, whereas the HTA generated higher outputs during TBP. The OPL in the HTA was likely heavier in TBP than in BBT, whereas no differences related to this variable were found in the PTA. Despite the apparent superiority of ballistics to produce power, it seems that in elite athletes, the strength-power training routine might affect the ability to apply high forces at very-high velocities.     

Time-motion analysis of goalball players in attacks: differences of the player positions and the throwing techniques*

In this study, we aimed to analyse goalball players time-motion variables (distance covered, time spent, maximum and average velocities) in official goalball match attacks, taking into account the attack phases (preparation and throwing), player position (centres and wings) and throwing techniques (frontal, spin and between the legs). A total of 365 attacks were assessed using a video based method (2D) through manual tracking using the Dvideo system. Inferential non-parametric statistics were applied for comparison of preparation vs. throwing phase, wings vs. centres and, among the throwing techniques, frontal, spin and between the legs. Significant differences were found between the attack preparation versus the throwing phase for all player time-motion variables: distance covered, time spent, maximum player velocity and average player velocity. Wing players performed most of the throws (85%) and covered longer distances than centres (1.65 vs 0.31 m). The between the legs and the spin throwing techniques presented greater values for most of the time-motion variables (distance covered, time spent and maximum player velocity) than did the frontal technique in both attack phases. These findings provide important information regarding players’ movement patterns during goalball matches that can be used to plan more effective training.     

The suitability of Sanders’ model for calculation of the propulsive force generated by the hands during sculling motion

This study examined whether Sanders’ model is suitable for estimating accurately the propulsive force generated by the hands’ motion in swimming comparing the calculated force obtained using the model and the measured force during an actual propulsive action. The measured and calculated forces were obtained from 13 swimmers who, while tethered, performed a sculling motion in a prone position for the purpose of displacing the body by moving it forward. Kinematic analyses were conducted to obtain the calculated force, while the measured force was obtained via the use of a load cell. The calculated force was lower than the measured force and accounted for only a small part of the variation in the measured force. The forces could not be used interchangeably, and there were fixed and proportional differences between them. Consequently, this study indicates that Sanders’ model is not suitable for estimating accurately the propulsive force generated by the swimmer’s hands during sculling motion. However, research that integrates analyses from different approaches could result in improvements to the model that would render it applicable for estimating the propulsive forces during movements that are characterised by directional changes of the hands.     

Collaborative science activities and the social construction of understanding of physical science concepts by pre-service teachears in Fiji

The research reported was part of a larger study that was founded on the belief that the introduction of a teaching style informed by a constructivist view of teaching and learning and utilising collaborative group work would improve the understanding of science concepts held by pre-service primary teacher education studients in Fuji. It sought to test this belief, and to explore whether such an approach would be effective for students from different ethnic groups. Two intact classes in a teachers' college studied a physical science unit, one class being involved in extensive collaborative group activities and the other, the comparison group, being taught in the usual transmissive fashion. An interpretive methodology was adopted, involving a range of data sources and analytical techniques. Data presented here support the claim that the collaborative group work stimulated increased levels of discussion and fostered deeper conceptual understanding. There were, however, some unexpected learning outcomes for some students. Implications for science education in Fiji and similar locations are discussed.     

有无正当理由违约中的损害赔偿——从案例分析的角度

通过对国际体育仲裁违约合同造成损害赔偿的案例分析,提出没有固定的规则可以适用所有的案例,唯一确定的是所谓的"积极利益"或"预期利益"原则。因此,裁定方确定赔偿金是以假设违约未发生,受害方应当获得利益大小为标准。任何人都不应当试图创设一个固定规则,因为尝试创设规则是不明智的,它将导致裁定方因固定规则被迫以某种方式裁定,并不能实现双方当事人及体育领域所追求的公正、合理的结果。文章认为由裁定方在考虑到所有情形的前提以积极利益原则为首要原则确定最合适的赔偿金。