Time – motion analysis of professional rugby union players during match-play

Abstract

The aim of this study was to quantify the movement patterns of various playing positions during professional rugby union match-play, such that the relative importance of aerobic and anaerobic energy pathways to performance could be estimated. Video analysis was conducted of individual players (n=29) from the Otago Highlanders during six “Super 12” representative fixtures. Each movement was coded as one of six speeds of locomotion (standing still, walking, jogging, cruising, sprinting, and utility), three states of non-running intensive exertion (rucking/mauling, tackling, and scrummaging), and three discrete activities (kicking, jumping, passing). The results indicated significant demands on all energy systems in all playing positions, yet implied a greater reliance on anaerobic glycolytic metabolism in forwards, due primarily to their regular involvement in non-running intense activities such as rucking, mauling, scrummaging, and tackling. Positional group comparisons indicated that while the greatest differences existed between forwards and backs, each positional group had its own unique demands. Front row forwards were mostly involved in activities involving gaining/retaining possession, back row forwards tended to play more of a pseudo back-line role, performing less rucking/mauling than front row forwards, yet being more involved in aspects of broken play such as sprinting and tackling. While outside backs tended to specialize in the running aspects of play, inside backs tended to show greater involvement in confrontational aspects of play such as rucking/mauling and tackling. These results suggest that rugby training and fitness testing should be tailored specifically to positional groups rather than simply differentiating between forwards and backs.     

A Probabilistic Model for Evaluation of Volleyball Scoring Systems

Abstract

A probabilistic model for the game of volleyball is developed to evaluate alternative scoring systems. This Markov chain model is then recursively solved, to determine the distribution of the number of serves per game and the probability that a given team wins. These results are then used to evaluate the effects on the game of volleyball of a proposed change in the scoring system.     

The Use of Dynamic Assessment by Educational Psychologists in the UK

Training in Dynamic Assessment (DA) was rarely available in the UK until 1994. This is the first study to explore the outcomes of its availability in terms of the practice of DA and perceptions about it among educational psychologists (EPs). One hundred and nineteen EPs, who had taken positive steps to inform themselves about DA by undertaking some degree of training or by joining a DA interest group, were surveyed to explore the extent of their initial training in DA, subsequent use of it and issues of implementation. Overall, the 88 responses (74%) received suggest, among those surveyed, widespread awareness of DA as a model of cognitive assessment and positive attitudes to it, coupled with a low level of implementation. The low level of use was frequently attributed to insufficient training in DA, to lack of time due to other assessment priorities, often set by the local education authority, and to lack of the ongoing expert support felt to be necessary to maintain use of a demanding form of assessment. The authors take the position that the EP's repertoire would be enriched by improved knowledge of and training in DA. The research raises important issues for cognitive assessment and raises the broader question whether there is a need for the more proactive involvement of educators in enhancing the cognitive functioning of children.     

Time - motion analysis of professional rugby union players during match-play

The aim of this study was to quantify the movement patterns of various playing positions during professional rugby union match-play, such that the relative importance of aerobic and anaerobic energy pathways to performance could be estimated. Video analysis was conducted of individual players (n=29) from the Otago Highlanders during six "Super 12" representative fixtures. Each movement was coded as one of six speeds of locomotion (standing still, walking, jogging, cruising, sprinting, and utility), three states of non-running intensive exertion (rucking/mauling, tackling, and scrummaging), and three discrete activities (kicking, jumping, passing). The results indicated significant demands on all energy systems in all playing positions, yet implied a greater reliance on anaerobic glycolytic metabolism in forwards, due primarily to their regular involvement in non-running intense activities such as rucking, mauling, scrummaging, and tackling. Positional group comparisons indicated that while the greatest differences existed between forwards and backs, each positional group had its own unique demands. Front row forwards were mostly involved in activities involving gaining/retaining possession, back row forwards tended to play more of a pseudo back-line role, performing less rucking/mauling than front row forwards, yet being more involved in aspects of broken play such as sprinting and tackling. While outside backs tended to specialize in the running aspects of play, inside backs tended to show greater involvement in confrontational aspects of play such as rucking/mauling and tackling. These results suggest that rugby training and fitness testing should be tailored specifically to positional groups rather than simply differentiating between forwards and backs.     

Effective inclusive education: Equipping education professionals with necessary skills and knowledge

As a result of educational reforms, students with disabilities are educated in inclusive settings to a greater degree than ever before. Regrettably, many teachers report that they feel unprepared to work effectively with these students. Because teacher effectiveness is strongly linked to student outcomes, these perceptions of inadequacy are clearly problematic. Improved teacher preparation is a necessity. Yet, teacher educators face their own challenges when trying to keep up with current literature and a rapidly expanding knowledge base. Web-based technology offers solutions to some of these challenges, yet not all Web-based resources are valid or reliable. The IRIS Center for Training Enhancements, funded by the U.S. Department of Education, provides free online resources for those working with struggling learners and students with disabilities. The resources are developed in collaboration with leading educational researchers, are highly rated, and are heavily used in multiple countries to improve the quality of teacher education.     

Urea production during prolonged swimming

Male interscholastic swimmers (n = 8) completed a 4572 m training swim in in 62 +/- 1.1 min (means +/- S.E.) with terminal heart rate and blood lactate of 152 +/- 6 beats min-1 and 6.9 +/- 0.89 mM, respectively. Sweat rate (0.48 +/- 0.095 l. h-1) was lower than similar intensity cycling (1.5 +/- 0.13 l. h-1) or running (1.1 +/- 0.14 l. h-1). Post-swim serum urea N (11.6 +/- 0.71 mM) was elevated (P less than 0.05) vs pre-swim (4.6 +/- 0.39 mM). Post-swim urine volume (860 +/- 75 ml 24 h-1) was reduced (P less than 0.07) and resulted in an elevated (P less than 0.05), but delayed (24-84 h), post-exercise urea N excretion. Although the reduced urine and sweat production during the swim undoubtedly contributed to the elevated serum urea, there must be another explanation because together they could only account for 38% of the observed increase. On the basis of the magnitude of serum urea increase, it appears that the swim caused an increase in urea production (amino acid oxidation). The failure to observe larger increases in urinary urea during recovery indicates that either urea excretion following exercise continues for prolonged periods of time (greater than 48 h) or another significant mode of nitrogen excretion exists.     

Effect of order of exercise on performance during a complex training session in rugby players

In this study, we examined the acute effects of manipulating exercise order when combining countermovement jumps and loaded parallel squats in a complex training session, and the acute effects of countermovement jumps and loaded parallel squats on sprinting performance. Eight rugby players participated in five trials, including two that involved performing loaded parallel squats followed by countermovement jumps or vice versa in a randomized cross-over design. Peak rate of force development and peak force were measured during countermovement jumps and loaded parallel squats. Peak power, jump height, and duration of amortization phase were also determined during the countermovement jumps. Peak force during squatting was significantly greater in both cross-over treatments (loaded parallel squats-countermovement jumps and countermovement jumps-loaded parallel squats) compared with the control (P 相似文献   

Work‐to‐School Mentoring: Childcare Center Directors and Teachers’ Return to School

As supervisors of preschool teachers, childcare center directors are well‐situated to mentor their staff to pursue higher education. Telephone interviews with 78 directors examined their role as mentors in encouraging preschool teachers to take college classes. Educational mentoring was shown to be distinct from career mentoring. Logistic regressions showed that the director’s educational mentoring of teachers and teachers’ aides was associated with greater college attendance, whereas career mentoring was related to less attendance. Furthermore, the director’s confidence staff members’ ability to complete an Associate’s degree promoted college enrollment. Finally, some directors appeared to be transformational leaders who created an education‐friendly climate for their entire staffs. These findings suggest that the workplace is an under‐researched, critical context for work‐to‐school mentoring.