Self-presentational concerns and competitive anxiety

The purpose of this study was to improve understanding of the link between self-presentational concerns and competitive anxiety. Specifically, we examined (a) associations among self-presentational concerns and competitive state anxiety dimensional symptom responses using the modified Competitive State Anxiety Inventory-2 (CSAI-2; Martens, Vealey, & Burton, 1990) and (b) whether self-presentational concerns mediate trait-state anxiety relationships. In addressing these matters, we also examined the factor structure and composition of the Self-Presentation in Sport Questionnaire (SPSQ; Wilson & Eklund, 1998). Results showed that self-presentational concerns were positively associated with intensity and frequency dimensional symptoms and negatively associated with direction symptoms. Results also showed that self-presentational concerns demonstrated consistently higher associations with the cognitive component and the intensity symptom of the CSAI-2 state measures. Results showed no support for the notion that self-presentational concerns mediate the trait-state anxiety relationship. When examining the factor structure and composition of the SPSQ, the results from two independent athlete samples support the tenability of an abbreviated 21-item four-factor model. Thus the newly constituted scale is recommended for measuring self-presentational concerns in sport.     

生活方式干预对心血管疾病危险因素的影响——美国HELPS项目成果

摘要：心血管疾病（CVD）一直是全世界最主要的死因。由于CVD等慢性疾病对健康的威胁越来越大,有必要开展生活方式干预项目以控制这些疾病的危险因素。本研究的目的是评估美国的重要慢病干预项目—HELPS治疗型生活方式改变（TLC）项目对减少CVD危险因素和其他慢性疾病的有效性。方法：140位大学教职工参加为期12周的HELPS TLC项目,干预前后用配对t检验对其体重、BMI、腰围（WC）、6分钟步行距离（6MWD）、空腹血脂和血糖进行测定和比较。结果：干预后6MWD显著增加,总胆固醇（TC）和WC显著下降。对“高危”参与者进一步分析显示：BMI（-1.5±0.5,-3.9%）、TC（- 22.8±4.0,-9.0%）、LDL（- 14.1±4.9,9.3%）和血糖（-6.9±2.2,-6.1%）均显著下降;男性腰围（-4.5±0.8,-10%）显著减小,女性未见显著改变（-1.5±0.5,-4.0%）。此外,体重的变化与TC（r=0.43）、LDL（r=0.35）和血糖（r=0.44）的变化均显著相关。结论：参加12周的生活方式干预项目可以使CVD危险因素减少,特别是在CVD“高危”个体中。HELPS TLC项目的远期效果还待进一步深入研究。     

信息系统研究中的尺度设计——一个实现一维性评价的范例

由于尺度在评价信息系统产品时具有多方面的作用,因此在信息系统领域,设计和评价用来度量潜在现象的尺度一直是人们感兴趣的话题。一般来说,尺度的度量性质是通过传统技术来评价的,如项与总体相关法(item—to—total correlations),a系数和探索因子法(ex-ploratory factor analysis)。尽管在探索状况下它们很有效,但它们却很少提供有关一维性的评价。一维尺度只度量单一的特征。这一性质是测度论中的一条基本假设,它在精确度量变量间的相关关系中也是相当重要的。这篇论文中主要讲了一个设计一维尺度的范例,这个范例是从市场研究、教育、心理学中的成熟技术得到启发,使用了确认因子分析法(CFA—Con-firmatory Factor Analysis)来评价度量性质。重要的是,CFA对一维性的解释比传统方法更严格,并且在许多情况下对尺度的可接受性会得到不同的结论。     

录音机—写作的得力助手

帮助你评改自己的文稿作家常常面对自己的文稿,飘飘然地沉浸在自我陶醉之中。他们自以为自己的文章文笔不凡,不,简直是惊人之作,以至于连一个标点符号都不想改动。其实这种心情在学生们的身上何尝不是如此呢?为了医治这种病态的自我欣赏,我们奉劝那些进行写作的同学,写作时不妨把自己的草稿对着录音机读一遍,录下音来,然后丢开稿子听一听录音。这样做,可以动员听觉来参与文章的评改。效果如何呢?你会发现草稿里那些拗口的语句——不合语法的结构、重复罗唆的词语、含糊不清的文笔转折——种种失着败笔竟一下子钻了出来。然后,谢天谢地,动手修改吧!     

Optimizing segmental movement in the jumping header in soccer

This study looks at segmental movements in the jumping header from an optimization viewpoint. Investigations on the header so far have focused on head restriction in the movement but have not clarified how and to what extent body segments influence the performance of the skill. In the present study a biomechanical model was used to analyze the jumping header in simulated competition to give a clear picture of an optimized header. Skilled soccer players headed balls at speeds of 13 m x s(-1) the results indicated that the head moves as a free non-restricted segment in the jumping header and should be allowed to do so, even though much soccer literature says otherwise to prevent injuries. The arm movement showed individual characteristics and gave no general advantages in optimizing ball speed after impact in the header The movement of the legs was, on the other hand, the single most important factor in the skill. Therefore, coaches and players shouldfocus on developing muscle strength in the stomach, back and pelvis and should put no restrictions on head and arm movement to optimize the jumping header.     

力量素质和决定力量素质的诸因素

沃罗比耶夫是苏联原国家举重队总教练,医学副博士,本人亦曾经多次创造90公斤级举重世界纪录。他在1977年所著《举重运动的生理学与训练》一书,系统地总结了苏联优秀举重运动员的训练经验,并使之与运动生物力学、运动生理学、运动医学紧密结合,融为一体。该书资料丰富,数椐处理严格、论据明确,科学性强。对我国举重教练员、运动员、运动医生有较大参考价值。由于时隔五年,个别论述已失之陈旧。本刊拟摘其精华,编译登载。本期刊登的是该书第二章“力量素质和决定力量素质的各种因素”的主要内容,以后将陆续编译刊登其它部分。     

Sequential muscle activity and its functional role in the upper extremity and trunk during overarm throwing

The proximal-to-distal segmental sequence has been identified in many sports activities, including baseball pitching and ball kicking. However, proximal-to-distal sequential muscle activity has not been identified. The aims of this study were to establish whether sequential muscle activity does occur and, if it does, to determine its functional role. We recorded surface electromyograms (EMGs) for 17 muscles from the upper extremity and abdomen during overarm throwing and detected the onset and peak times as indices of muscle activity. The following electromyographic properties were commonly identified in the participants. First, sequential muscle activity was observed from the scapular protractors to the shoulder horizontal flexors and from the shoulder horizontal flexors to the elbow extensor, but not from the elbow extensor to the wrist flexor or forearm pronator. Secondly, the external oblique contralateral to the throwing arm became activated before the ipsilateral external oblique. This sequence is considered to be very effective for the generation of high force and energy in the trunk. Thirdly, the ipsilateral external oblique began its activity almost at foot strike. Finally, the main activity of the rectus abdominis appeared just before the point of release.     

甜蜜的家庭

~~甜蜜的家庭@John H.Payne @张梦华