Centre of mass kinematics of fast bowling in cricket

Kinematic studies have shown that fast bowlers have run-up velocities, based on centre of mass velocity calculations, which are comparable to elite javelin throwers. In this study, 34 fast bowlers (22.3 +/- 3.7 years) of premier grade level and above were tested using a three-dimensional (3-D) motion analysis system (240 Hz). Bowlers were divided into four speed groups: slow-medium, medium, medium-fast, and fast. The mean centre of mass velocity at back foot contact (run-up speed) was 5.3 +/- 0.6 m/s. Centre of mass velocity at back foot contact was significantly faster in the fastest two bowling groups compared to the slow-medium bowling group. In addition, stepwise multiple regression analysis showed that the centre of mass deceleration over the delivery stride phase was the strongest predictor of ball speed in the faster bowling groups. In conclusion, centre of mass kinematics are an important determinant of ball speed generation in fast bowlers. In particular, bowlers able to coordinate their bowling action with periods of centre of mass deceleration may be more likely to generate high ball speed.     

An evaluation of biomechanical measures of bowling action legality in cricket

Cricket bowling is traditionally thought to be a rigid-arm motion, allowing no elbow straightening during the delivery phase. Conversely, research has shown that a perfectly rigid arm through delivery is practically unattainable, which has led to rule changes over the past years. The current rule requires a bowler not to increase the elbow angle by more than 15 degrees, thus requiring a measurement to confirm legality in "suspect" bowlers. The aims of this study were to evaluate whether the current rule is maintained over a range of bowlers and bowling styles, and to ascertain whether other kinematics measures may better differentiate between legal and suspect bowling actions. Eighty-three bowlers of varying pace were analysed using reflective markers and a high-speed (240 Hz) eight-camera motion analysis system in a laboratory. The change in elbow segment angle (minimum angle between the arm and forearm), the change in elbow extension angle with respect to the flexion-extension axis of a joint coordinate system, and the elbow extension angular velocity at ball release were measured. We found that bowlers generally bowled within a change in elbow extension angle of 15.5 degrees. However, this limit was unable to differentiate groups of bowlers from those who were suspected of throwing in the past. Improved differentiation was attained using the elbow extension angular velocity at ball release. The elbow extension angular velocity at ball release may be conceptually more valid than the elbow extension angle in determining which bowlers use the velocity-contributing mechanisms of a throw. Also, a high value of elbow extension angular velocity at ball release may be related to the visual impression of throwing. Therefore, it is recommended that researchers and cricket legislators examine the feasibility of specifying a limit to the elbow extension angular velocity at ball release to determine bowling legality.     

Global Mistrust in News: The Impact of Social Media on Trust

ABSTRACT

Digital platforms such as search engines and social media have become major gateways to news. Algorithms are used to deliver news that is consistent with consumers’ preferences and individuals share news through their online social networks. This networked environment has resulted in growing uncertainty about online information which has had an impact on news industries globally. While it is well established that perceptions of trust in news found on social media or via search engines are lower than traditional news media, there has been less discussion about the impact of social media use on perceptions of trust in the news media more broadly. This study fills that gap by examining the influence of social media as news sources and pathways to news on perceptions of the level of news trust at a country level. A secondary data analysis of a 26-country survey in 2016 and 2019 was conducted. The analysis revealed an increase in social media use for accessing news resulted in a decline in trust in news media generally across the globe. Higher levels of general mistrust in news were related to an increased use of sharing of news. This paper argues the use of social media for news is closely linked to the increase in news mistrust, which is likely to continue to rise as the number of people using social media to access news continues to grow.     

Effects of Transactional and Transformational Governance on Academic Teaching: Empirical evidence from two types of higher education institutions

The article considers the importance of examining how members of university governing bodies understand and perform their roles in the politically complex context of contemporary higher education. While a growing body of scholarly literature is devoted to the study of university governance, much of this work neglects the human aspects of decision‐making in the presence of the competing interests, societal expectations and government intervention currently besetting universities. This article argues that, given this context, understanding of the factors impacting on university governing body effectiveness will be greatly enhanced by interpretive analysis of qualitative data obtained from university governance practitioners themselves.     

Constructive readings of interactive episodes: examining ethics in physical education from a social constructionist perspective

In this paper we illustrate how ways of thinking about ethics are tied up with sport and physical education practice and introduce an alternative approach that can help to develop ethical pedagogies. We begin by locating socio-moral education in physical education within historical and contemporary pedagogical scholarship. Our argument is that the work of today's physical educators is still shaped by claims that were made about school sport in the nineteenth century and that sport scholars have long had difficulties proving these claims empirically. Rather than search for data that can confirm or refute claims of moral learning, we examine how incidents related to moral behaviour occur during physical education lessons. To do this we draw on data from an ethnographic investigation of a school in North Western Switzerland. Specifically, we present three episodes of interaction in three different physical education lessons. To make sense of these episodes, we introduce a social constructionist perspective. The main assumptions of this perspective are: (1) meanings are created through dialogue and consensus and are context-relative; (2) interactions between people are joint accomplishments; and (3) contexts affect how people interact with one another. Equipped with a constructionist framework, we then inspect the interactive episodes more closely. We include brief discussions of how constructionist understandings might inform ethics pedagogies in the future, suggesting that practitioners should be cautious of universal understandings of ethics, consider pupils as members of communities that are held together by shared practices, provide space for pupils to position themselves differently during lessons and, finally, account for contextual factors when evaluating pupils’ actions.     

Differences in impact characteristics,joint kinetics and measurement reliability between forehand and backhand forward badminton lunges

ABSTRACT

This study identified the effect of badminton lunging directions on impact characteristics, joint kinetics and measurement reliability. A total of 14 badminton players performed 20 lunges in both forehand and backhand sides. Ground reaction force (GRF) and three-dimensional joint moment variables were determined for further analyses. Paired t-tests and Wilcoxon signed-rank tests were performed to determine any differences between the two lunge directions and intra-class correlation (ICC) and sequential averaging analysis (SAA) were used to estimate the minimum number of trials. Compared to the forehand side, participants experienced significantly larger total GRF impulse (+ 3.8%, p = 0.021) and transverse moment (hip + 63.5%, p < 0.001; knee + 80.7%, p = 0.011), but smaller hip (?7.7%), knee (?18.7%) and ankle frontal moments (?58.0%, p < 0.05) in backhand lunges. The minimum number of trials was similar for both lunge directions, as the averaged absolute differences was less than one in both ICC and SAA. Furthermore, smaller minimal number of trials was determined by the ICC (7.9–8.0), compared with the SAA approach (9.5–10.3). Lunge direction would influence GRF and joint loading, but not on the measurement reliability. These results give important insights to establish performance or equipment evaluation protocols during badminton lunges.     

The effects of knowledge management on innovative success – An empirical analysis of German firms

The aim of this paper is to analyse the effects of knowledge management on the innovation success of firms in Germany. We look at innovative firms in the period from 2000 to 2002 taken from the Mannheim Innovation Panel and estimate the effect of collaborative measures of knowledge management on the immediate economic success of different types of innovations. The results of our matching analysis reveal that firms which apply knowledge management perform better in terms of higher-than-average shares of turnover with innovative products compared to their twins. We do not find a significant effect of knowledge management on the share of cost reductions with process innovation.     

School mathematics registers in a context of low academic expectations

We investigate the different school mathematical discourses that are made available for students who all share an unfavourable social and economical position and experiences of low achievement in primary school, and who have been streamed into three different ability groups at the very beginning of secondary school. Our investigation is built on the premise that schools distribute different forms of knowledge to different social groups and thus provide different opportunities to develop consciousness. We look at teacher–student interactions as expressions of social structure at the micro-level and as constituents of social structure on the macrolevel. Employing analytic tools from social semiotics, we carried out a register analysis of the school mathematical discourse in each stream. We found systematic differences and linked them to the work of Dowling (1998) on the construction of ability and its implications for social hierarchies. As a result, the upper of the three streams was freed from a discourse of low expectations, while such a discourse was reinforced for the lower stream. Finally, we will discuss our findings in relation to the contemporary debate about the role of mathematics education in social stratification.