共查询到20条相似文献，搜索用时 687 毫秒
1.
Luis Augusto Teixeira Elke Dos Santos Lima Mariana Marília Franzoni 《Journal of sports sciences》2013,31(9):943-950
The time course of movement timing reprogramming was examined in a task requiring temporal coincidence of the conclusion of a forehand drive with the arrival of a moving luminous target at the end of an electronic trackway. The moving target departed from one end of the trackway at a constant velocity of 2?m . s?1, and for a part of the trials its velocity was increased to 3?m . s?1. Target velocity was modified at different moments during stimulus displacement, producing times-to-arrival after velocity increment (TAVIs) from 100 to 600?ms. The effect of specific practice on movement reprogramming was also examined. The results showed early adjustments to the action (TAVIs = 100?–?200?ms) that seemed to be stereotyped, while feedback-based corrections were implemented only at TAVIs of 300?ms or longer. Temporal accuracy was progressively increased as longer TAVIs were provided up to 600?ms. Skill training led to an overall increment of temporal accuracy, but no effect of specific practice was found. The results indicate that timing reprogramming in interceptive actions is a continuous process limited mainly by intrinsic factors: latency to initiate more effective adjustments to the action, and rate-of-movement timing reprogramming. 相似文献
2.
Yoichi Ohta 《Journal of sports sciences》2017,35(23):2304-2312
The present study aimed to clarify the effects of oncoming target velocities on the ability of rapid force production and accuracy and variability of simultaneous control of both force production intensity and timing. Twenty male participants (age: 21.0 ± 1.4 years) performed rapid gripping with a handgrip dynamometer to coincide with the arrival of an oncoming target by using a horizontal electronic trackway. The oncoming target velocities were 4, 8, and 12 m · s?1, which were randomly produced. The grip force required was 30% of the maximal voluntary contraction. Although the peak force (Pf) and rate of force development (RFD) increased with increasing target velocity, the value of the RFD to Pf ratio was constant across the 3 target velocities. The accuracy of both force production intensity and timing decreased at higher target velocities. Moreover, the intrapersonal variability in temporal parameters was lower in the fast target velocity condition, but constant variability in 3 target velocities was observed in force intensity parameters. These results suggest that oncoming target velocity does not intrinsically affect the ability for rapid force production. However, the oncoming target velocity affects accuracy and variability of force production intensity and timing during rapid force production. 相似文献
3.
Donald Siegel 《Research quarterly for exercise and sport》2013,84(2):128-131
The purpose of this study was to determine how the manipulation of movement duration affects components of fractionated reaction time and presumably motor programming. Twelve subjects, in a simple reaction time paradigm, responded to an auditory signal by executing an elbow flexion movement in the sagittal plane through a range of motion of 100° in 150, 300, 600 and 1200 ms. Results indicated no changes in motor time but small increments in premotor and reaction time through the 600 ms condition. At 1200 ms, reaction time increased faster than premotor time, and this appeared to be predominantly a consequence of an increment in motor time. These data were interpreted to be supportive of the notion that movement duration is related to response complexity and the time required for motor programming. 相似文献
4.
Sherwood DE 《Research quarterly for exercise and sport》2010,81(3):300-309
According to closed-loop accounts of motor control, movement errors are detected by comparing sensory feedback to an acquired reference state. Differences between the reference state and the movement-produced feedback results in an error signal that serves as a basis for a correction. The main question addressed in the current study was how distance, movement time, and velocity influence both spatial or temporal error detection. Forty college-aged participants (30 women and 10 men) performed rapid aiming movements over 30 degrees or 50 degrees in either 210 ms or 350 ms without vision. The participants verbally estimated the distance moved and the movement time during acquisition before knowledge of results was given and during an immediate retention test without knowledge of results. Spatial and temporal objective-subjective correlations were greater in the 210-ms condition compared to the 350-ms condition, but were not related to movement velocity. 相似文献
5.
《European Journal of Sport Science》2013,13(2):130-138
Abstract This study investigated stimulus velocity effect on manual asymmetry during planning and execution of a complex coincidence-anticipation task. Left- and right-handers were required to press six buttons sequentially in conjunction with visual stimulus provided by a coincidence-anticipation device. Results showed that (1) stimulus velocity affected timing response and timing accuracy only for right-handers, who responded faster but less accurately in the fast stimulus velocity, (2) manual asymmetries for both handedness groups revealed a left-hand advantage for initiating the movement, and a preferred-hand advantage for movement time. The preferred-hand advantage in timing accuracy was only observed in the fast stimulus velocity. These findings are discussed in the framework of the hemispheric functional lateralisation. 相似文献
6.
太极柔力球柔力球作为一项结合了太极拳和球类运动特点的全民健身体育项目,在全民健身计划的推动下,正朝着竞技化、规范化的趋势发展,并在不断摸索、创新科学的训练手段和方法。文章为迎合项目的这一发展趋势,借鉴运动生物力学等其他学科的先进成果和方法,在本项目中创新的使用了红外线录像分析,对太极柔力球核心难度之一的拍头向下绕翻技术进行运动学分析,以期建立规范的动作技术模型,使动作最佳化、合理化,进一步促进项目的规范性发展。研究结果显示：太极柔力球拍头向下绕翻技术离心阶段运动较向心阶段运动时间长,球拍运动速度较快,角速度变化幅度大,呈现出先加速后减速的趋势,翻拍动作在向心阶段完成;肩关节活动幅度小,肘关节角速度在向心运动绕翻动作时有明显的加大,腕关节变化幅度小;在动作的向心阶段,手指与腕部配合完成预捏拍动作,为下一周动作做积极准备。 相似文献
7.
Charles H. Shea John B. Krampitz Homer Tolson Alan A. Ashby Rose M. Howard William S. Husak 《Research quarterly for exercise and sport》2013,84(1):86-99
Abstract The present experiments examined the effects of stimulus velocity, stimulus duration, and stimulus uncertainty on the spatial-temporal structure and timing accuracy of coincident timing responses. The results of Experiment 1 indicated that the response structure for aimed movements differed from that of ballistic movements but response accuracy was comparable for both movement conditions. However, when information concerning the stimulus velocity was provided, the responses to the faster stimuli (i.e., stimuli of shorter duration) appeared to be “speeded up” copies of those to slower stimuli and response accuracy increased as the stimulus velocity increased (i.e., stimulus duration decreased). When the stimulus velocity was not known, subjects initiated a common response for approximately 260 msec and response accuracy appeared to decrease as the stimulus velocity increased (i.e., stimulus duration decreased). Experiment 2 indicated that the stimulus duration rather than the stimulus velocity was the major determiner of both the spatial-temporal structure and timing accuracy and that a very fast and a very slow stimulus will be responded to similarly when the stimulus duration remains constant. 相似文献
8.
In three experiments, participants were asked to produce a prescribed temporal sequence of key presses. The number of elements in a key press sequence, the movement time of the elements, and uniformity of the timing elements comprising the sequence were manipulated. If the processing of the sequence structure was independent of the processing of elements comprising the sequence, increasing the number of the elements in the sequence should affect the production of the sequence but not the proficiency with which the individual elements are, produced. Increasing the movement time of the elements, however, should affect the production of the elements but have little, if any, effect on the integrity of the sequence. The findings indicated that increasing the number of elements negatively affected sequence production when the elements were nonuniform but had little or no effect when elements were uniform. Alternatively, element production was affected by movement time but not number of elements. The results of these experiments appear to confirm the independence of sequence and element production. However, Experiment 3, in which the uniformity of the elements was directly contrasted, found strong evidence for coarticulatory influences in the learning processes, whereby the longer and shorter than average elements in the sequence negatively affected the sequence integrity and the production of the individual elements. When faced with a nonuniformn timing pattern, participants appear to elongate or shrink individual elements of a uniform timing pattern to fit the desired sequence requirements. The result is that the longer or shorter than average elements require more practice to produce correctly, tend to regress across retention intervals, and are generally less stable than the elements nearer the average. 相似文献
9.
In rapid interceptive actions such as hitting a baseball, cricket ball or tennis ball, ball speed varies between trials, and players have to compensate the time lag by controlling the moment of movement onset and movement duration. Previous studies have found that these two variables can flexibly co-vary and are robustly influenced by target speed (i.e. velocity-coupling effect: faster movement for faster target). However, some studies reported an interpersonal variability in the timing control strategy and the relationship between the strategy and temporal accuracy in rapid interception is unclear. We used a baseball-simulated rapid interceptive task to assess this issue. Under relatively easy time constraints, there was a large interpersonal variability, and participants were distinctively divided into two groups: those who mainly modulated their movement duration and those who mainly controlled their movement onset. When the time constraint became severe, the second strategy shifted to the first strategy in most of the second group participants. In the both cases, being able to mainly control movement onset resulted in higher temporal accuracy. These results suggest that minimising the velocity-coupling effect is an important factor to achieve high temporal accuracy in rapid interception. 相似文献
10.
Germano Gallicchio Thomas Finkenzeller Gerold Sattlecker Stefan Lindinger 《European Journal of Sport Science》2019,19(5):567-575
This study examined the influence of physical exercise on the relation between shooting accuracy and the phase of the cardiac cycle in which the shot is fired. Thirteen experienced biathletes (8 females, mean age 17 years) fired from the standing position at rest and right after a submaximal exercise on a bicycle ergometer. Shooting accuracy and the timing of each shot relative to the R-waves of the electrocardiogram (ECG) were recorded. Best shots (with greatest accuracy) and worst shots (with lowest accuracy) were fired prevalently in different phases of the cardiac cycle. In the rest condition, best shots were fired less frequently from 200 to 300?ms and more frequently from 500 to 600?ms after the R-wave, compared to worst shots. In the exercise condition, best shots were fired less frequently from 100 to 200?ms after the R-wave and from 20% to 30% of the R-R interval, compared to worst shots. These findings support the hypothesis that shooting accuracy is influenced by the cardiac cycle phase due to the ballistocardiac recoil generated at each heartbeat. To achieve best results athletes could be trained (e.g. through biofeedback) to fire within a specific phase of the cardiac cycle. 相似文献
11.
The purpose of this study was to examine performance differences in arm movement control (programmingvs. "on-line" control) between children with and without attention deficit hyperactivity disorder (ADHD). Twenty children (10 with ADHD and 10 without ADHD) from the ages of 8 to 13 years participated in the study. On the surface of a digitizer, each participant completed three types of aiming arm movements (10 trials for each) and 10 baseline trials (without accuracy requirement). Multivariate analyses of variance with repeated measures were used to analyze the variables of reaction time, movement time, normalized jerk, intersegment-interval (ISI), and movement timing. Children with ADHD appeared to use "on-line " monitoring during the arm movement and did not perform the entire movement sequence as afunctional unit. They executed the arm movements more slowly, had greater variability in movement timing, and demonstrated longer ISIs than their counterparts. Children with ADHD had multiple peaks in the velocity profiles. Children withoutADHD, however, appeared to program their entire arm movements and execute the sequence as a unit. Their velocity profiles were symmetrical with a single peak, and the movement segments were temporally coordinated. Thesefindings suggested that cognitive functions are important resources for controlling rapid aiming arm movements. Children with ADHD might rely more on visual feedback during the movements, which resulted in slower and more variant movement outcomes than children who did not have ADHD. 相似文献
12.
Individuals practiced two unique discrete sequence production tasks that differed in their relative time profile in either a blocked or random practice schedule. Each participant was subsequently administered a "precuing" protocol to examine the cost of initially compiling or modifying the plan for an upcoming movement's relative timing. The findings indicated that, in general, random practice facilitated the programming of the required movement timing, and this was accomplished while exhibiting greater accuracy in movement production. Participants exposed to random practice exhibited the greatest motor programming benefit, when a modification to an already prepared movement timing profile was required. When movement timing was only partially constructed prior to the imperative signal, the individuals who were trained in blocked and random practice formats accrued a similar cost to complete the programming process. These data provide additional support for the recent claim of Immink & Wright (2001) that at least some of the benefit from experience in a random as opposed to blocked training context can be localized to superior development and implementation of the motor programming process before executing the movement. 相似文献
13.
女子铅球运动员滑步阶段速度节奏特征研究 总被引：4，自引：0，他引：4
文章对我国优秀女子铅球运动员滑步阶段相关运动环节及铅球的速度节奏进行了研究。结果表明，滑步阶段的团身移殿－两腿摆蹬结束瞬间，移臀、两腿摆蹬动作配合的动作方向、距离及时间是决定各运动环节速度的主要因素。在右脚距离地面－右脚着地瞬间，右腿主动收拉右小腿是保持身体运动惯性，维持身体重心继续移动的重要环节。移臀与积极蹬右踝动作是滑步阶段整体速度行进的关键。 相似文献
14.
《European Journal of Sport Science》2013,13(4):364-371
Abstract The aim of the present work is to examine the differences between two groups of fencers with different levels of competition, elite and medium level. The timing parameters of the response reaction have been compared together with the kinetic variables which determine the sequence of segmented participation used during the lunge with a change in target during movement. A total of 30 male sword fencers participated, 13 elite and 17 medium level. Two force platforms recorded the horizontal component of the force and the start of the movement. One system filmed the movement in 3D, recording the spatial positions of 11 markers, while another system projected a mobile target over a screen. For synchronisation, an electronic signal enabled all the systems to be started simultaneously. Among the timing parameters of the reaction response, the choice reaction time (CRT) to the target change during the lunge was measured. The results revealed differences between the groups regarding the flight time, horizontal velocity at the end of the acceleration phase, and the length of the lunge, these being higher for the elite group, as well as other variables related to the temporal sequence of movement. No significant differences have been found in the simple reaction time or in CRT. According to the literature, the CRT appears to improve with sports practice, although this factor did not differentiate the elite from medium-level fencers. The coordination of fencing movements, that is, the right technique, constitutes a factor that differentiates elite fencers from medium-level ones. 相似文献
15.
Reduced feedback during practice has been shown to be detrimental to movement accuracy in children but not in young adults. We hypothesized that the reduced accuracy is attributable to reduced movement parameter learning but not pattern learning in children. A rapid arm movement task that required the acquisition of a motorpattern scaled to specific spatial and temporal parameters was used to investigate the effects of feedback (FB) frequency (100% vs. 62% faded) on motor learning differences between 19 school-age children and 19 young adults. Adults and children practiced the task for 200 trials under the 100% or faded FB condition on day 1 and returned on day 2 for a no-FB retention test. On the retention test, children who practiced with reduced feedback performed with greater temporal parameter errors, but not pattern error than children who received frequent feedback. Motor skill learning in children is influenced byfeedback frequency during practice that affects parameter learning but not pattern learning. 相似文献
16.
Paul Ward A. Mark Williams Simon J. Bennett 《Research quarterly for exercise and sport》2013,84(1):107-112
Purpose The purposes of this study were to: (a) examine the effect of experience and goal constraints (speed, accuracy) on kicking patterns; (b) determine if effective striking mass was independent of ankle velocity at impact; and (c) determine the accuracy of kicks relative to independent factors. Method Twenty participants were recruited to kick at 3 different velocities with and without an accuracy requirement. Multivariate analysis of variance determined if relative timing of joint angular velocities changed during the kick. Chi-square analysis determined if calculated effective mass was independent of ankle velocity at impact. Analysis of variance (ANOVA) was used to examine differences in absolute constant error and variable error according to independent factors. Results Results indicated that experience and speed affect absolute timing of joint velocities with no changes in the relative timing of peak joint velocity across independent factors. Chi-square analysis indicated that calculated effective mass is not independent of ankle velocity. ANOVA indicated that experienced performers displayed less variability error than did inexperienced performers. Conclusion It was concluded that: (a) Experience, velocity, and accuracy do not affect the relative timing of kicks; (b) kickers trade ankle velocity at impact for greater effective striking mass and ball velocity; and (c) variability in ball placement is affected by experience. 相似文献
17.
18.
鞭腿动作是散打腿法技术的核心,将散打鞭腿动作简化为一个二环节运动链模型,对散打鞭腿动作的髋、膝关节和大腿、小腿环节在三维平面内进行位置矢量的确定,以此确定在鞭腿动作中,各关节和环节的运动学参数,然后确定目标函数(末端速度V),建立了人体鞭腿动作的三维运动学方程,将鞭腿动作各环节要领数学化描述,结论认为:(1)鞭腿动作中大腿的角速度由腰部角速度和髋关节角速度决定,小腿的角速度由大腿和膝关节的角速度决定,三者密切配合共同决定着鞭腿末端的速度;(2)在T1阶,大小腿下潜完曲度不易超过450,在进攻腿离地瞬间,小腿环节的角速度大于大腿环节的角速度时最有利于膝关节速度的增加,进攻退离地时膝关节的角速度主要由小腿蹬地时的地面反作用力决定;(3)在T2阶段,大小腿充分折叠有利于膝关节角速度的加大;(4)人体的鞭腿环节链模型中,鞭打原理遵从动量由近端环节向远端环节传递的原理,通过髋关节及时有效的制动可使膝关节动量增加,通过膝关节的制动可使动量传递到末端,引起末端加速。(5)在散打鞭腿环节链模型中只有多环节和关节依次协调配合才能使末端发挥最佳击打效果。 相似文献
19.
回顾与分析在篮球运动中眼动研究的文献,这些研究多数采用的是专家—新手范式;实验材料多为运动实践的影像场景或者静态的比赛图片;视觉搜索行为和预测能力是观测的主要指标;眼动记录技术与计算机技术的结合,使得眼动数据记录的精度和速度有了较大的提高。研究采用的模式比较泛化;实验的条件、环境和过程与真实的比赛存在着很大的差距;研究涉及的篮球技术动作和战术情境较少;研究的对象比较单一,职能位置考虑不足是当前篮球运动中眼动研究存在的一些问题。 相似文献
20.
A kinematic analysis of rugby lineout throwing 总被引：1，自引：1，他引：0
To characterize rugby union lineout throwing technique, three experienced male rugby players performed throwing trials under varying conditions of distance and trajectory. Motion analysis permitted the recovery of joint centre coordinates at 120 Hz and the construction of a three-dimensional linked segment model for calculation of joint angle and centre of mass time histories. All participants exhibited greater accuracy at shorter throwing distances, although the accuracy decrement was less in players of higher standard. Participants demonstrated different alterations in technique when performing throws of longer distances, either showing increased magnitudes of upper-body joint angle velocities (less accurate thrower) or lower-body joint velocities (more accurate thrower). The most elite thrower exhibited greater consistency in timing of peak joint angle velocities, with an overall standard deviation of 0.008 s compared with 0.027 s for the least accurate thrower. Data from participants of lesser ability suggest that changes are made to both magnitudes and timing of joint kinematics, which leads to increased variability in performance. The implications for players and coaches include the need to develop core strength to permit limited changes to the timing and magnitude of upper-body joint actions while allowing sufficient end-point velocity to be imparted on the ball. 相似文献