Neuromuscular control mechanisms and strategy in arm movements of attempted supranormal speed

Rapid, goal-directed elbow flexion movements were examined under interacting conditions of inertial loading and resistance to movement initiation. The resistance ceased when movement began, resulting in quick release movements. Inertial load slowed the movement and lengthened the agonist and antagonist electromyographic (EMG) burst durations. The quick release resulted in larger accelerations but only minimal changes in peak velocity. Most aspects of the triphasic EMG pattern were little affected by the quick release, but the build up of agonist EMG and the corresponding rate of static force development differed markedly between load and quick release conditions. These and other data suggest that the specific pattern of agonist muscle activation is set according to neuromuscular constraints of the antagonist muscle and the expectation of movement dynamics.     

The Psychophysics of Kinesthesis for Positioning Responses: The Physical Stimulus-Psychological Response Relationship

Abstract

The physical stimulus-psychological response relationship has been described as being either a prothetic or a metathetic continuum. That is, as the stimulus intensity increases, the response magnitude increases (prothetic) or stays the same (metathetic). The first experiment of this study considered this relationship for a movement having the final limb position, or location, as its goal. The second experiment focused on an extent movement. Subjects were tested on a linear positioning apparatus in both experiments using the method of constant stimuli for determining thresholds. On the basis of the Weber ratios and the JND's for the three increasing movement locations and extents, a metathetic continuum was determined as best describing location movements, while a prothetic continuum was considered more appropriate for extent movements. JND's indicated sensitive discrimination for location movements (1.08 to 1.39 cm for 25 to 75 cm locations) and less precise discrimination capability for extent movements (2.49 to 5.76 cm for 25 to 75 cm extents). Results are discussed in terms of their possible implications for addressing issues related to mechanisms subserving active kinesthesis, and in terms of their implications for experimental procedures for learning and memory investigations using discrete positioning responses.     

运动和衰老(上)

传统上将衰老过程叙述为进行性的降低健康后导致最终衰弱和死亡。虽然多种生理机能随年龄而下降,但缺乏体力活动引起多种机能降低作用将加速衰老的过程。无论是从分子、细胞到组织和器官系统任一个水平上都会由于缺乏运动导致机能水平降低,这一状况可以因运动而缓解或甚至逆转,对维持生命健康带来很大希望。本文讨论了由于增加体力活动使一些生理机能改善的机制。     

Age-related differences in the control of spatial aiming movements.

The experiment was designed to (a) examine age-related differences in the control of aiming movements, and (b) determine the locus of slowing in movement execution of older adults. Fitts's (1954) index of difficulty (ID) was used to manipulate movement execution demands, and kinematics were used to examine the response characteristics. Twelve young and 12 older adults performed simple aiming movements 10 cm or 20 cm in amplitude to targets of 0.5 cm, 1.0 cm, or 2.0 cm in width, resulting in IDs ranging from 3.32 to 6.32. The results for both young and older subjects support the prediction that movement time (MT) increases as a function of ID and that older adults are significantly slower and more affected by increases in ID than the young adults. Velocity and acceleration profiles of the older adults' movements displayed very different response characteristics than those of the young adults. The results suggest that older adults emphasize accuracy of response and are concerned with the latter phase of the movement in order to contact a target accurately.     

论"健康老龄化"与老年体育

体育在"健康老龄化"这一社会系统工程的实现中具有积极的现实意义.采取切合实际的策略与手段是推进老年体育发展,促进"健康老龄化"实现的有力保障.     

Women and exercise in aging

Aging is associated with physiological declines, notably a decrease in bone mineral density (BMD) and lean body mass, with a concurrent increase in body fat and central adiposity. Interest in women and aging is of particular interest partly as a result of gender specific responses to aging, particularly as a result of menopause. It is possible that the onset of menopause may augment the physiological decline associated with aging and inactivity. More so, a higher incidence of metabolic syndrome (an accumulation of cardiovascular disease risk factors including obesity, low-density lipoprotein cholesterol, high blood pressure, and high fasting glucose) has been shown in middle-aged women during the postmenopausal period. This is due in part to the drastic changes in body composition, as previously discussed, but also a change in physical activity (PA) levels. Sarcopenia is an age related decrease in the cross-sectional area of skeletal muscle fibers that consequently leads to a decline in physical function, gait speed, balance, coordination, decreased BMD, and quality of life. PA plays an essential role in combating physiological decline associated with aging. Maintenance of adequate levels of PA can result in increased longevity and a reduced risk for metabolic disease along with other chronic diseases. The aim of this paper is to review relevant literature, examine current PA guidelines, and provide recommendations specific to women based on current research.     

试论大学生健美操的创编

近年来，健美操已是普通高校体育课中不可缺少的项目之一，也是大学生最为喜欢的课程之一。根据学生的能力以及实际情况进行健美操成套动作的创编，更新健美操操化动作，并适当增加一些难度动作，使学生始终保持新鲜感，提高兴趣。     

浅谈速度滑冰摆臂技术

针对我国运动员摆臂技术的现状,对摆臂技术加以分析,并着重剖析摆臂的加速和制动的关系,及对蹬冰和自由滑行的作用.介绍了摆臂技术的训练原则、手段和应注意的问题.     

Head, eye and arm coordination in table tennis

The aim of this study was to determine the role of head, eye and arm movements during the execution of a table tennis forehand stroke. Three-dimensional kinematic analysis of line-of-gaze, arm and ball was used to describe visual and motor behaviour. Skilled and less skilled participants returned the ball to cued right or left target areas under three levels of temporal constraint: pre-, early- and late-cue conditions. In the pre- and early-cue conditions, both high and low skill participants tracked the ball early in flight and kept gaze stable on a location in advance of the ball before ball-bat contact. Skilled participants demonstrated an earlier onset of ball tracking and recorded higher performance accuracy than less skilled counterparts. The manipulation of cue condition showed the limits of adaptation to maintain accuracy on the target. Participants were able to accommodate the constraints imposed by the early-cue condition by using a shorter quiet eye duration, earlier quiet eye offset and reduced arm velocity at contact. In the late-cue condition, modifications to gaze, head and arm movements were not sufficient to preserve accuracy. The findings highlight the functional coupling between perception and action during time-constrained, goal-directed actions.     

武术散打技术动作协调性与注意分配的相关性

通过对武术散打运动员技术动作的研究发现,武术技术动作协调性与注意分配能力有关,动作操作的注意分配能力好的运动员,技术动作的协调性也好,反之亦然,两者呈高度相关的关系。阐述了注意分配与协调性高度相关的原因及提高注意分配能力的途径。     

右臂动脉变异报告

2001年春季我们在解剖一具男性尸体时，有明显异常发现：右臂腋动脉平对第二肋外缘处分成三支。     

大幅度展掌摆臂对100m运动员步频、步幅的影响分析

运用文献资料、录像分析等方法，对世界优秀100m运动员格林、贝利、刘易斯、乔伊娜、琼斯、奥蒂、德费斯和我国十运会100m男、女前8名运动员的摆臂方式进行比较分析。结果表明：刘易斯、格林、乔伊娜、琼斯等运用的大幅度展掌摆臂技术不仅可以使后蹬力量增大，步频增加，而且对增大步幅也有贡献，但其摆动方式需要较大的肩带力量作保证，否则会影响摆动速度。     

Electromyography and the study of sports movements: A review

Within electromyography (EMG), a particular speciality has been developed wherein the aim is to use EMG for the study of muscular function and co‐ordination. This area of research is usually called kinesiological EMG. The general aims of kinesiological EMG are to analyse the function and co‐ordination of muscles in different movements and postures, in healthy subjects as well as in the disabled, in skilled actions as well as during training, in humans as well as in animals, under laboratory conditions as well as during daily or vocational activities. This is often done by a combination of electromyographical and kinesiological or biomechanical measurement techniques.

Because there are over 400 skeletal muscles in the human body and both irregular and complex involvement of the muscles may occur in neuromuscular diseases and in voluntary occupational or sports movements, it is impossible to sample all of the muscles of the entire body during the performance of complex motor skills. In addition, the measurement of kinesiological EMG in sport and specific field circumstances, such as the track and/or soccer field, the alpine ski slope, the swimming pool and the ice rink, demands a specific technological and methodological approach, adaptable to both the field and the sport circumstances.

Sport movement techniques and skills, training approaches and methods, ergonomic verification of the human‐machine interaction have, amongst others, a highly specialized muscular activity in common. The knowledge of such muscular action in all its aspects, its evaluation and its feedback should allow for the optimization of movement, of sports materials, of training possibilities and, in the end, of sports performance.

Drawing conclusions from a review of the EMG research of 32 sports, covering over 100 different complex skills, including methodological approaches, is an impossible task. We have attempted to set standards concerning the EMG methodology at the beginning of this review. Electromyography and sports is a vast area and a complete review is impossible, as information will be found scattered in many different journals, including those on the sports sciences, ergonomics, biomechanics, applied physiology, in different congress proceedings, and so on. Consequently, many important aspects and possibly important publications may have been omitted from this review.     

竞技健美操难度动作训练方法

难度动作在竞技健美操比赛中是影响运动成绩的重要因素之一。结合健美操训练实践就难度动作的训练方法进行了探讨。合理运用难度动作的训练方法，是竞技健美操训练科学进行的重要保障。     

Evaluation of compatibility effects in the precuing of arm and direction parameters

The present study evaluated the role of compatibility effects in the precuing of arm and direction parameters. In the first two experiments different stimulus and response arrangements were examined. For all three experiments the spatial precue and imperative stimuli were compatibly assigned to responses (i.e., a direct correspondence existed between the stimulus and response locations). Experiments 1 and 2 indirectly tested the effect of decision processes required by the stimulus-response set. Experiment 1 replicated previous research that has found longer reaction times for the direction uncertain parameter as compared to arm uncertain. Experiment 2 examined the precuing of arm and direction parameters with stimuli that maintained right-left arrangements for both parameters. Unlike Experiment 1, reaction times did not differ for precuing the two movement parameters. Experiment 3 directly examined the effect of differential decision requirements from up-down spatial stimuli and right-left spatial stimuli for a single parameter. In support of results from the first two experiments, results indicated longer reaction times for decisions from up-down stimuli as compared to right-left stimuli. Because reaction times for precued movement parameters are a function of the stimulus and response arrangements used, differences in reaction times are most likely due to compatibility effects arising from differences in the spatial arrangements of the precued stimulus and response set.     

析110米栏跑过栏时的摆臂及腿臂动作配合

本文指出了我国高栏水平较五、六十年代相比的落后原因，并以此为依据，在分析了跨栏步基本技术后，提出了摆臂在跨栏时的重要作用，进而阐述了腿臂动作合理配合的最佳技术特点。     

A biomechanical comparison of dominant and non-dominant arm throws for speed and accuracy

Training a non-dominant limb may increase a competitor's ability to perform with either side of his or her body and confer an advantage over competitors that use one side of the body exclusively. The aim of this study was to determine the kinematic differences between dominant and non-dominant arm throwing techniques for speed and accuracy in Under-17 and Under-19 high-performance cricketers. Seven participants performed ten throws for each arm (dominant/non-dominant) and condition (speed/accuracy) at a target positioned 10 m in front of them. Three-dimensional kinematic variables were measured using a Vicon motion analysis system. Digital footage was used to calculate stride data, ball speed, and record target accuracy. Data were analysed using repeated-measures analysis of variance and chi-squared tests. The non-dominant arm throws had significantly lower maximum lead knee lift, did not extend the lead knee in the arm acceleration phase, had significantly less elbow flexion before extension, had significantly less shoulder external rotation at the start of the arm acceleration phase, did not have a delay between the initiation of pelvic and upper torso internal rotation, and displayed a less than optimal coordination pattern. A speed-accuracy trade-off existed for the dominant arm throws. No trade-off was identified for the non-dominant arm throws. Through an enhanced understanding of how throwing technique varies between dominant and non-dominant arms, an opportunity exists for a performance-enhancing programme to be implemented so that ambidexterity of the throwing skill can be improved.