Effect of swimming velocity on arm coordination in the front crawl: a dynamic analysis

We examined the preferred mode of arm coordination in 14 elite male front-crawl swimmers. Each swimmer performed eight successive swim trials in which target velocity increased from the swimmer's usual 3000-m velocity to his maximal velocity. Actual swim velocity, stroke rate, stroke length and the different arm stroke phases were then calculated from video analysis. Arm coordination was quantified by an index of coordination based on the lag time between the propulsive phases of each arm. The index expressed the three coordination modes in the front crawl: opposition, catch-up and superposition. First, in line with the dynamic approach to movement coordination, the index of coordination could be considered as an order parameter that qualitatively captured arm coordination. Second, two coordination modes were observed: a catch-up pattern (index of coordination?=??8.43%) consisting of a lag time between the propulsive phases of each arm, and a relative opposition pattern (index of coordination?=?0.89%) in which the propulsive phase of one arm ended when the propulsive phase of the other arm began. An abrupt change in the coordination pattern occurred at the critical velocity of 1.8?m?·?s^?1, which corresponded to the 100-m pace: the swimmers switched from catch-up to relative opposition. This change in coordination resulted in a reorganization of the arm phases: the duration of the entry and catch phase decreased, while the duration of the pull and push phases increased in relation to the whole stroke. Third, these changes were coupled to increased stroke rate and decreased stroke length, indicating that stroke rate, stroke length, the stroke rate/stroke length ratio, as well as velocity, could be considered as control parameters. The control parameters can be manipulated to facilitate the emergence of specific coordination modes, which is highly relevant to training and learning. By adjusting the control and order parameters within the context of a specific race distance, both coach and swimmer will be able to detect the best adapted pattern for a given race pace and follow how arm coordination changes over the course of training.     

Why do high jumpers use a curved approach?

Currently, all elite high jumpers use the Fosbury Flop technique with a curved approach. This suggests that the curved approach presents some clear advantage, although there is no general agreement upon the mechanism or the mechanics. This study aimed to determine the characteristics of the approach curve and to investigate how it contributes to the generation of somersault rotation. A simple theoretical model was used to demonstrate that a tightening approach curve would change the inward lean towards the centre of the curve into outwards lean. Three-dimensional video analysis was used to record the performances of two elite male high jumpers in competition. It was found that in each case the radius of the approach curve and the inward lean angle both decreased towards the end of the approach. The amount of outward lean angular velocity generated was shown to be a major proportion of the required somersault angular velocity for a jump. It was concluded that the main advantage of a curved approach was that it resulted in the generation of somersault velocity providing the curve tightened towards the end of the approach.     

Changing students' attitudes towards risky motor tasks: An application of the IZOF model

The aim of this study was to evaluate the effectiveness of an intervention programme in the physical education setting designed to change attitudes and emotions triggered by potentially risky motor tasks. The individual zones of optimal functioning (IZOF) model was used as a theoretical framework for the study. Italian male and female high school students (N = 84) took part in a 12 lesson intervention and in test?–?retest sessions. The assessment was conducted using the Motor Activity Anxiety Test to measure the students' approach-avoidance attitudes in the face of physical education tasks purported to engender strong emotional reactions. An idiosyncratic emotional profile was also implemented using a list of pleasant/unpleasant emotional adjectives. Two experimental groups were involved in the learning and performing of several potentially risky, highly emotion-arousing tasks, while two control groups were engaged in low-risk team sports. According to the hypothesis of the study, the programme was effective in decreasing the students' avoidance tendencies towards thrilling tasks and in increasing optimal?–?pleasant emotions. Our findings also demonstrated the feasibility and utility of applying the IZOF model to the context of physical education.     

日本终身学习体系构建的保障及其启示

上世纪70年代左右,终身教育和终身学习理念的相继提出给世界各国发展教育提供了新的视野。日本终身教育在四十多年发展过程中积累了丰富的理论和实践经验,走在了亚洲甚至是世界的前列。因此,探讨日本终身学习体系构建的保障,从法律法规体系、机构设施体系和财政投入体系三方面进行解析,对我国构建和发展终身教育有借鉴作用。     

The Effects of Three Styles of Teaching on the Psychomotor Performance And Social Skill Development of Fifth Grade Children

Abstract

The effects of Mosston's teaching styles B, C and E were examined in terms of motor skill acquisition and social skill development of fifth grade children. Ninety-six children, randomly selected and randomly assigned to one of three treatment groups, were taught a hockey accuracy task. Motor performance data were collected prior to, midway through, and following training; they were analyzed within groups, to determine if learning was evident, and across groups, to examine the relative effectiveness of these three styles of teaching. Social behavior patterns observed during learner-to-learner interaction were also examined during a second task in which pairs of learners were asked to “help” each other learn the task. A 3 × 3 analysis of variance with repeated measures revealed that (1) all three groups learned the task and (2) they learned comparably well. It was concluded that these three styles of teaching are all effective in facilitating learning of this type of motor task. Style C, an arrangement in whcih learners work in pairs, one performing the task while being provided with formative feedback by the other, was found not only to produce comparable learning, but to significantly enhance social skill development on those behaviors associated with giving feedback and receiving it from a peer.     

Influence of Decision-Making on Attitudes,Creativity, Motor Skills and Self-Concept in Elementary Children

Abstract

Attitudes, creativity, self-concept and motor skills were measured to determine the influence of decision-making on elementary children. Three groups of children (N = 208) were tested, one group was taught with the teacher dominating all classroom decisions, another group was encouraged to share in the decision-making, and a third group served as a control. Data were collected immediately before and after an eight-week instructional period. MANCOVA indicated that the two treatment groups had significantly higher scores than did the control group, and the shared decision-making group scored significantly higher than the teacher dominated group on measures of creativity, motor skills and self-concept. A 2 (treatment) × 2 (sex) × 5 (grade) ANOVA revealed significantly more positive attitude scores for children allowed to make decisions regarding their learning. Further, Pearson product-moment correlation showed the tested variables to be independent measures of a child's development.     

《楞严经疏解蒙钞》的文献学价值

《楞严经疏解蒙钞》是钱谦益晚年的一部佛经疏释的力作,是他反经明教的佛教改革思想的具体体现,显示出了钱氏作为学者式文人的学术修养,在佛经文献疏钞类著作中具有独到的文献价值,在目录、校勘等方面都显示出钱氏深厚的文献学功力。     

Effects of Two Instructional Approaches on Skill Development,Knowledge, and Game Performance

Two instructional approaches that have been of interest in promoting sport have been the Sport Education Model (SEM) and the Traditional Style (TS) of teaching physical education. The purpose of this study was to investigate how SEM and TS would affect skill development, knowledge, and game performance for volleyball at the secondary level. A 2 × 3 (group × time) research design was utilized on 47 secondary students testing volleyball skills, knowledge, and game performance. Participants were placed in either the SEM or the TS via stratified randomization, and then were tested pre, mid, and post intervention through the 20-lesson volleyball unit. The 2 × 3 repeated measures Analysis of Variances (ANOVAs) with Bonferroni correction revealed no significant difference between models for skills and knowledge, but there was for game performance for group [F(1, 45) = 10.27, p < .008, η² = .19], time [F(2, 90) = 8.62, p < .008, η² = .16], and group × time interaction [F(2, 90) = 8.43, p < .008, η² = .16]. If the goal of the physical education program is to promote quality game play, the SEM may be more effective than the TS.     

Tool for Assessing Responsibility-Based Education (TARE): Instrument Development,Content Validity,and Inter-Rater Reliability

Numerous scholars have stressed the importance of personal and social responsibility in physical activity settings; however, there is a lack of instrumentation to study the implementation of responsibility-based teaching strategies. The development, content validity, and initial inter-rater reliability testing of the Tool for Assessing Responsibility-Based Education (TARE) are described here. Inter-rater agreement was calculated for paired observations focused on 2 different teachers delivering a total of 18 separate physical education lessons for students in grades 1 through 6. Findings indicate that the Tool for Assessing Responsibility-Based Education provides scores with adequate inter-rater reliability. The procedures employed in this study proved feasible and enable observers to characterize the implementation of responsibility-based teaching in physical education. The Tool for Assessing Responsibility-Based Education has numerous research and training applications relative to the Teaching Personal and Social Responsibility model (Hellison, 2003 Hellison, D. 2003. Teaching responsibility through physical activity, 2nd, 15–38. Champaign, IL: Human Kinetics.  [Google Scholar]) and the national content standards for K–12 physical education, specifically Standard 5: Exhibits responsible personal and social behavior that respects self and others in physical activity settings (National Association for Sport and Physical Education, 2004 National Association for Sport and Physical Education (NASPE). 2004. Moving into the future. National standards for physical education, 2nd, 39–43. Reston, VA: Author.  [Google Scholar]).     

Book Reviews

This study examined the teaching of games via a tactical approach (also known as teaching games for understanding) from the theoretical perspective of social constructivism. A pilot study (of student teachers (STs) and pupils) informed the ‘main’ study which included collecting data on 49 STs, 58 cooperating teachers (CTs) and 1177 pupils. ST data were collected through videotaping (lessons), interviews and questionnaires; CT data through interviews and questionnaires; and pupil data through questionnaires. Data analysis techniques included systematic coding of teaching behaviours through computer software, using constant comparison to code open-ended question responses, and computing frequencies of Likert-scale question responses. T-tests were used to compare pre- and post-CT workshop data. Findings suggest that STs’ teaching of the tactical approach was in line with a social constructivist perspective, in part because lessons were student-centred. Overall student activity was 53% of all lessons taught, and STs facilitated pupil learning through several question and answer scenarios. Pupils wrote that they enjoyed playing games in what amounted to ‘authentic’ settings. Their responses also suggest that learning took place through ‘legitimate peripheral participation in communities of practice’ and this facilitated pupil movement through the ‘zone of proximal development’. There were indications that pupil experiences were mediated by ST competence. CTs reported that an in-service workshop on the tactical approach and mentoring was beneficial and subsequent pairings with STs elicited positive feelings from both parties.