悬吊废用和血管紧张素Ⅱ对大鼠骨骼肌运动终板的影响

目的:研究悬吊废用和外源性血管紧张素Ⅱ对大鼠骨骼肌运动终板形态和功能的影响。方法:雌性SD大鼠32只,体重(200~220)g,分成4组,每组8只,包括安静对照组(C)、安静加血管紧张素组(CA)、尾部悬吊组(T)、悬吊加血管紧张素组(TA)。T和TA组采用尾悬吊造成腓肠肌的废用萎缩。CA和TA组利用缓释泵稳定地对体内释放血管紧张素Ⅱ(AngⅡ)。取材后,氯化金(AuCl3)染色法显示运动终板的形态;乙酰胆碱酯酶(AchE)染色法显示AchE的相对含量;Western blot法测定神经营养因子-3(NT-3)的相对含量。结果:与C组相比,T组运动终板核面积和AchE相对含量均显著性下降(P<0.01),而TA组两指标比T组有显著性的提高(P<0.01);与C组相比,CA组NT-3表达显著性升高(P<0.01),而T组NT-3的表达显著性下降(P<0.01);TA组NT-3显著高于T组(P<0.05)。结论:悬吊废用会导致运动神经末梢和运动终板发生退化;AngⅡ有可能通过神经营养因子的作用阻止肌肉运动终板的退化。     

运用外部注意焦点提高高水平选手开放式运动技能学习效率的实验研究

针对"动作限制假说"是否适用于开放式运动技能、以及该假说的生物力学基础等问题,以14名北京体育大学校队队员为受试者进行实验。结果表明:外部注意焦点指导促进高水平选手开放式运动技能的动作表现,而内部注意指导则阻碍其动作表现。生物力学图像解析的数据也表明,在外部注意焦点指导下,高水平选手不同动作间的髋-膝、踝-膝协调模式一致性更高,说明外部注意焦点指导能够促进高水平选手更加稳定地完成开放式运动技能。     

美国芝加哥新教师入职引导制度的效能考察

美国芝加哥为解决公立学校新教师的大量流失问题,采取了一套"入职引导"制度。根据教育的情境化研究理论,教师个体的身份背景、课堂要求以及学校环境对新教师的教学体验和继续从教意愿具有重要影响。新教师入职引导制度主要对这三方面产生一定的调节作用,以留住优秀教师。通过调查研究发现,教学指导和同事的支持对新教师具有重要意义,但是有些入职引导方案的效果不甚明显,需要改进。     

Reexamining the factor structure of the test of gross motor development – second edition: Application of exploratory structural equation modeling

The Test of Gross Motor Development – Second Edition (TGMD-2) is a widely used evaluation tool of children’s fundamental motor skills (FMS). This study illustrates how exploratory structural equation modeling (ESEM) addresses current limitations associated with TGMD-2 factor structure. Using the normative dataset from the TGMD-2 manual, we test alternative measurement models using ESEM and confirmatory factor analysis (CFA) and assess measurement invariance between boys and girls and across age. Findings highlight complexity and poor discriminant validity in the two-factor solution that is accentuated when relying on CFA independent clusters assumption. Results also demonstrate differential item functioning (DIF) across age for three of the 12 TGMD-2 indicators. Taken together, this study provides valuable information on the need to reevaluate the TGMD-2 factor structure and can guide revisions for the third edition of the TGMD.     

Laying the foundations for physical literacy in Wales: the contribution of the Foundation Phase to the development of physical literacy

Background: The Foundation Phase in Wales is a play-based curriculum for pupils aged 3–7 years old. Children learn through more holistic areas of learning in place of traditional subjects. As such, the subject of physical education in its traditional form no longer exists for pupils under the age of 7 in Wales. In light of the role of physical education in developing physical literacy and in particular the importance of this age group for laying the foundations of movement for lifelong engagement in physical activity, the disappearance of physical education from the curriculum could be deemed to be a concern.

Purpose: The purpose of this study was to explore the Foundation Phase as a naturalistic intervention and examine its contribution to the development of physical literacy.

Participants and setting: Participants included year 1 pupils (N?=?49) aged 5 and 6 from two schools in contrasting locations. A smaller group within each class was selected through purposive sampling for the repeated measures assessments (N?=?18).

Research design and methods: A complementarity mixed-method design combined quantitative and qualitative methods to study the Foundation Phase as a naturalistic intervention. Quantitative data were generated with the Test of Gross Motor Development-2 administered to the sample group of children from both schools as a quasi-repeated measure, the physical competence subscale of the Pictorial Scale of Perceived Competence and Social Acceptance and the Leuven Involvement Scale for Young Children. Qualitative data were generated throughout the study from the analysis of video and field notes through participant observation. Data from the mixed methods were analysed through complementarity to give a rich insight into pupils’ progress and experiences in relation to physical literacy.

Results: Overall analysis of the data from TGMD-2 showed significant improvements in the Gross Motor Quotient and Locomotor skills from T1 to T3, but no significant improvement in object control. Data from qualitative methods were analysed to explore processes that may account for these findings. Video and field notes complement the quantitative data highlighting that children were developing their locomotor skills in many aspects of their learning. Observations using the Leuven Involvement Scale indicated that children had high levels of involvement in their learning and apparent in video and field notes was pupils’ motivation for movement. Paired sample t-tests (N?=?18) conducted on the Harter and Pike perceived physical competence six-item score subscales (T1 and T3) indicated a significant difference in the mean perceived physical competence scores on the six-item scale between T1and T3. Qualitative data explored pupils’ confidence for movement in many areas of learning.

Conclusion: The combination of quantitative and qualitative data indicates that the Foundation Phase is an early childhood curriculum that lays the foundations of physical literacy with the exception of aspects of the physical competence, specifically object control skills. Although these skills only contribute to psychomotor aspects of physical literacy they are strongly associated with later engagement in physical activity. The development of specific physical skills such as object control skills may need more specialist input with early childhood pedagogy teachers trained in motor development to see significant improvements.     

The effect of a secondary cognitive task on landing mechanics and jump performance

Anterior cruciate ligament (ACL) injuries commonly occur during jump-landing tasks when individuals’ attention is simultaneously allocated to other objects and tasks. The purpose of the current study was to investigate the effect of allocation of attention imposed by a secondary cognitive task on landing mechanics and jump performance. Thirty-eight recreational athletes performed a jump-landing task in three conditions: no counting, counting backward by 1 s from a randomly given number, and counting backward by 7 s from a randomly given number. Three-dimensional kinematics and ground reaction forces were collected and analysed. Participants demonstrated decreased knee flexion angles at initial contact (p = 0.001) for the counting by 1 s condition compared with the no counting condition. Participants also showed increased peak posterior and vertical ground reaction forces during the first 100 ms of landing (p ≤ 0.023) and decreased jump height (p < 0.001) for the counting by 1 s and counting by 7 s conditions compared with the no counting condition. Imposition of a simultaneous cognitive challenge resulted in landing mechanics associated with increased ACL loading and decreased jump performance. ACL injury risk screening protocols and injury prevention programmes may incorporate cognitive tasks into jump-landing tasks to better simulate sports environments.     

Non-physical approaches to counteract age-related functional deterioration: Applications for rehabilitation and neural mechanisms

Normal and pathological ageing are associated with several motor impairments that reduce quality of life and represent a general challenge for public healthcare systems. Consequently, over the past decades, many scientists and physiotherapists dedicated their research to the development and improvement of safe and costless methods to counteract the progressive decline of motor functions with age. The urgency of finding new and easy to implement methods is even more paramount in case of acute pathologies (e.g. stroke or hip surgery). The frailty of older population makes it difficult or even impossible to use traditional physical therapy at an early stage after the occurrence of a pathology. To that purpose, non-physical approaches such as cognitive training (e.g. memory, attention training) and mental techniques (e.g. motor imagery) have grown in popularity for the elderly. Such methods, involving individual and/or group exercises, have shown particular effects on increasing or maintaining cognitive functions, as well as physical performances. Improving the motor function (especially in older age) requires an improvement of motor execution, i.e. the pathway from the brain motor areas to the muscle but also higher cognitive control. The present work reviews different non-physical interventions that can be used as a complementary approach by asymptomatic or frail older adults, and the effects thereof on functional performance. The use of cognitive training or motor imagery protocols is recommended when physical practice is limited or not possible. Finally, insights into the underlying neurophysiological mechanisms are proposed.     

Classification of playing position in elite junior Australian football using technical skill indicators

?In team sport, classifying playing position based on a players’ expressed skill sets can provide a guide to talent identification by enabling the recognition of performance attributes relative to playing position. Here, elite junior Australian football players were a priori classified into 1 of 4 common playing positions; forward, midfield, defence, and ruck. Three analysis approaches were used to assess the extent to which 12 in-game skill performance indicators could classify playing position. These were a linear discriminant analysis (LDA), random forest, and a PART decision list. The LDA produced classification accuracy of 56.8%, with class errors ranging from 19.6% (midfielders) to 75.0% (ruck). The random forest model performed at a slightly worse level (51.62%), with class errors ranging from 27.8% (midfielders) to 100% (ruck). The decision list revealed 6 rules capable of classifying playing position at accuracy of 70.1%, with class errors ranging from 14.4% (midfielders) to 100% (ruck). Although the PART decision list produced the greatest relative classification accuracy, the technical skill indicators reported were generally unable to accurately classify players according to their position using the 3 analysis approaches. This player homogeneity may complicate recruitment by constraining talent recruiter’s ability to objectively recognise distinctive positional attributes.     

Fundamental motor skills: A systematic review of terminology

The three aims of this systematic review are to describe: (1) use of the term fundamental motor/movement skills (FMS) in published articles; (2) the quality of definitions; and (3) relative use of process- and product- oriented assessments to measure FMS. The inclusion criteria included: (a) peer-reviewed article, (b) printed in English, (c) published between January 2000 and 31 December 2015, (d) presence of either the term “fundamental motor or movement skill” in the title and/or abstract, and (e) FMS were a measured outcome. There has been an increase in the number of publications on FMS in recent years, with the majority of studies conducted in Australia (n = 41, 33%). Approximately 24% of studies (n = 30) did not provide any explicit definition of FMS. A majority of studies reported the use of process-oriented measures (n = 98, 79%) compared to product-oriented measures (n = 23, 19%), and few studies used both (n = 6, 5%). We recommend that researchers provide: (1) an operational definition of FMS that states FMS are the “building blocks” (or similar terminology) of more advanced, complex movements; (2) specific categories of skills that compose FMS; and (3) at least one specific example of a FMS.     

Motor expertise interacts with physical enactment to enhance action memory

Previous research on action memory showed the advantage for performing the action in memorising the action phrases. We tested if performing the action would help participants with or without motor expertise to memorise the novel action poses. Thirty novel action poses performed by an expert were photographed to constitute memory and interference stimuli. Eighty college students observed to remember the randomly displayed stimuli; however, half were asked to perform the displayed stimuli. Both free-recall and recognition tests were administered immediately and 24 h after the memory task. The results showed that acting was better than observing for memorising the novel action poses, which not only promoted the absolute retention but also alleviated the retention loss caused by interference. Motor expertise enhanced the overall memory performance by promoting a deeper motor encoding. Based on our results, novices should act with (rather than just observe) the model to learn novel motor skills.