不同水平散打运动员动作的视觉选择反应时研究

文章采用文献资料法、专家访谈法、实验法、数理统计法,以前直拳、后直拳、后鞭腿三个动作为研究题材,对不同水平12名散打运动员的视觉选择反应时进行了测定和对比研究,一方面为散打运动员反应时进一步研究提供相关数据;另一方面为散打运动员科学训练的针对性、训练手段的有效性的动作视觉判断反应能力提供参考。研究结论得出：视觉选择反应时可用做比较不同水平散打运动员的一个参考指标。运动员预知一个动作与预知有两个动作中选择一个动作时,其反应时延长。而当运动员预知二个动作中选择一个动作与预知有三个动作中选择一个动作时,其反应时延长。     

Interaction between orthographic and graphomotor constraints in learning to write

We investigated the combined effects of orthographic and graphomotor constraints as a function of handwriting proficiency in children. Twenty-four first graders, 20 third graders, and 21 fifth graders wrote single five-letter words in cursive writing on a sheet of paper affixed to a digitizing tablet. The words were chosen according to two orthographic constraints, namely their lexical frequency and the graphemic complexity of the last three letters, and one graphomotor constraint resulting from the motor difficulty of tracing the first letter. In addition to massive improvements of handwriting with grade, the results revealed, in the youngest group only, an interaction between first-letter difficulty and lexical frequency. This finding suggests that, before handwriting movement becomes automated, the cognitive resources needed for retrieving word spelling interferes with motor processing while writing a difficult letter. When students start learning to write, they are particularly sensitive to the combination of orthographic and graphomotor constraints.     

Theory and practice in sport psychology and motor behaviour needs to be constrained by integrative modelling of brain and behaviour

Because of advances in technology, the non-invasive study of the human brain has enhanced the knowledge base within the neurosciences, resulting in an increased impact on the psychological study of human behaviour. We argue that application of this knowledge base should be considered in theoretical modelling within sport psychology and motor behaviour alongside existing ideas. We propose that interventions founded on current theoretical and empirical understanding in both psychology and the neurosciences may ultimately lead to greater benefits for athletes during practice and performance. As vehicles for exploring the arguments of a greater integration of psychology and neurosciences research, imagery and perception–action within the sport psychology and motor behaviour domains will serve as exemplars. Current neuroscience evidence will be discussed in relation to theoretical developments; the implications for sport scientists will be considered.     

PART VII: PSYCHOLOGY AND MOTOR CONTROL

The main aim of this study was to examine the age- and sex-associated variation in neuromuscular capacities of young distance runners. A secondary aim was to compare the magnitude of sex differences in young athletes in the same sport compared with the general population. Twenty-seven male and 27 female distance runners were enrolled in the study, whose ages ranged from 8.0 to 15.1 years at initial visit. Twenty males and 16 females were followed at approximate annual intervals for 4 or 5 years. Seven neuromuscular capacities were measured: quadrant jump, figure 8 run, standing long jump, vertical jump, flexed arm hang, sit-and-reach and sit-up. Age- and sex-associated variation was analysed by two-way analysis of variance. There were significant main effects for age for quadrant jump, figure 8 run, long jump, vertical jump, sit-and-reach and sit-up. There were significant main effects for sex for figure 8 run, long jump, vertical jump, flexed arm hang and sit-and-reach. The interaction between age and sex was statistically significant for long jump and vertical jump. In general, differences in neuromuscular agility (figure 8 run, quadrant jump) and explosiveness-power (long jump, vertical jump) between the sexes were attenuated before 13 years of age in young distance runners. However, during the adolescent growth spurt, differences in agility and power between the sexes emerged as a result of a continued increase in males and a plateau in females. Differences between the sexes in upper body neuromuscular endurance (flexed arm hang) and sit-and-reach persisted throughout the age range. The magnitude of sex differences between the runners and the general population varied by age and neuromuscular capacity.     

Objectively measured physical activity and psychosocial functioning in young children: The GECKO Drenthe cohort

ABSTRACT

The global trend in inactivity in children may be related to psychosocial problems. We investigated the cross-sectional association between physical activity (PA) levels and psychosocial functioning in 3.4–7.3-year-old children. Children from the Dutch GECKO birth cohort (N = 898; 51.6% boys) had PA levels assessed objectively by accelerometry (ActiGraph GT3X) for at least three days. Linear regression analysis was used for associations with psychosocial functioning (parent report of the Strengths and Difficulties Questionnaire), controlling for gender, age and socio-economic status. Higher total and moderate-to-vigorous PA levels (MVPA) were associated with higher Total Difficulty scores, and sedentary time to lower Total Difficulty scores. More time spent in MVPA was significantly associated to “hyperactivity/inattention” in both boys (Standardized B_BOYS = 0.192) and girls (Std.B_GIRLS = 0.139) whereas for the time in sedentary behaviour, a reverse association was found only in boys (Std.B_BOYS = ?0.230). In boys only, more time in MVPA (Std.B_BOYS = 0.154) and less time in sedentary behaviour (Std.B_BOYS = ?0.147), were significant determinants for ‘behavioural problems’. When using objectively measured PA, parents report more hyperactivity/inattention and behavioural problems in the more active children, and less in the more sedentary children, most clearly for boys. High levels of PA might be an indicator of psychosocial problems in young children.     

Cognitive to physical performance: a conceptual model for the role of motor simulation in performance

ABSTRACT

Motor simulation (MS) interventions incorporating motor imagery (MI), and more recently action observation (AO), are readily accepted as effective interventions to enhance motor skill performance. Existing models in the MS literature fail to consider the entire spectrum of MS interventions, focusing on MI or AO alone. This paper examines the theoretical basis and current understanding of MS efficacy, and introduces a novel, conceptual, Motor Simulation and Performance Model (MSPM) representing the performance improvements predicted to be associated with engaging with MS across expertise levels. The MSPM also outlines the multiple factors which regulate the efficacy of MS interventions. Based on the available evidence, the model suggests that MI will have a greater relative effect on performance as expertise increases, AO will have a greater effect in low skilled compared to high skilled performers, and that combined AO and MI (AO?+?MI) will be more effective than either MI or AO in isolation. The MSPM also depicts the additive effect of physical practice in conjunction with MS interventions. The MSPM represents for the first time the relative effects of various methods of motor learning based on evidence provided by the existing literature. It also highlights areas of research requiring further attention.     

Longitudinal associations between motor competence and different physical activity intensities: LabMed physical activity study

An appropriated level of motor competence is essential for children´s healthy growth and development and a key factor in the promotion of lifelong active lifestyles and health.

The purpose of this study was to examine associations between motor competence and different physical activity intensities (light, moderate, moderate-to-vigorous and vigorous physical activity), as well as total physical activity, over a two-year period, in adolescents. The sample comprised of 103 adolescents (13.49 ± 0.87 years, 53 girls), from the north of Portugal. Motor competence was evaluated with the body coordination test, Körperkoordination-Test-für-Kinder. Physical activity was objectively assessed with GT1M accelerometers (ActiGraph, Pensacola, FL, USA). Physical activity variables were expressed as proportions of accelerometer wear time. Regression analyses showed positive longitudinal associations between motor competence at baseline and moderate physical activity (B = 0.0033, p = 0.018), moderate-to-vigorous physical activity (B = 0.0052, p = 0.024) and total physical activity (B = 0.067, p = 0.040) at follow up, after adjustments for age, sex, the corresponding physical activity intensity at baseline, body mass index, pubertal stage and socioeconomic status. Our ?ndings highlight the importance of motor competence development to promote moderate-to-vigorous physical activity during adolescence.     

美国粗大动作发展测试(TGMD)解析与启示

基于测评体系应用的视角对美国粗大动作发展测试(Test of Gross Motor Development,TGMD)的产生发展背景、测量和评价系统、信效度、优缺点以及应用情况等方面开展研究,旨在促进我国儿童动作发展研究的开展。结果显示:TGMD的产生和发展具有特定的社会和学术背景;经过30年的发展,TGMD系列已经成为当前世界上应用最广泛的儿童粗大动作技能测评工具,被广泛应用的原因在于该测评体系的高度标准化。但TGMD存在着诸如指标适用性、过程性评价弊端等缺点,这需要引起使用者们的注意。文章通过对TGMD系列的解读分析,结合该测试目前在我国的应用现状,从思路和方法上提出对我国儿童动作发展研究的启示。     

变频技术与电动机调速

目前,我国电动机总装机容量达4.5亿千瓦,电动机总装机容量占目前总用电量的70%以上,其中近70%的电机拖动的负载是风机、泵类、压缩机等,而其中又有近70%的电机适合进行调速,即有约两亿千瓦的电机处在浪费运行的状态。因此如何实现电动机节能就显得非常重要。文章根据目前应用比较广泛的交流电动机,简单地介绍它的特点,结合以往的调速方式以及各自调速方式的优劣性,分析为什么要采用变频调速,而且如何实现变频调速,以及采用变频调速以后节能的效果。