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1.
Abstract

It is well documented that simple reaction time (RT) varies inversely with stimulus intensity, but there is disagreement as to which stimulus modality produces the fastest simple RT. An investigation was conducted to equate two stimulus modalities, auditory (A) and electrocutaneous (EC), using varying stimulus intensities in a simple RT protocol. A second investigation was then conducted to examine neuromotor characteristics of stimulus-evoked responses using previously equated A and EC stimuli of varying intensity from the first investigation. Results showed that RT, premotor time (PMT), and motor time (MT) were all inversely related to stimulus intensity, while maximum displacement (MAXD) was directly related to stimulus intensity, and movement time was not affected by stimulus intensity. We conclude that: (a) both central and peripheral components of RT are altered by varying stimulus intensities, and (b) rapid movements are enhanced by increasing stimulus intensity.  相似文献   

2.
Abstract

The superiority of motor set reaction time over sensory set reaction time has been accepted since the 1880s. Recently, however, there has been work favoring the sensory set. This study attempted to reconcile the varied findings. Woodworth had suggested that set and stimulus intensity interact. To test that presumed interaction and related ideas, the study proposed to determine not only the effect of motor set and sensory set on reaction time (RT) and muscle electrical activity (MEA), but also, the relationship between motor set and sensory set RT and motor set and sensory set MEA. Twenty-four subjects were tested in sessions that included the placement of electrodes on the motor end point of the extensor digitorum muscle, set instructions, practice, and data collection. Data collection consisted of recording of RT and MEA for 96 trials, 12 recordings at each of four levels of auditory stimulus intensity for each of the two sets. An ANOVA for repeated measures produced a significant interaction between set and intensity for RT; thus the Woodworth prediction was upheld. The results seem best explained in terms of signal detection theory and the attention demands of movement.  相似文献   

3.
Purpose

This study investigated whether within-task expertise affects the reported asymmetry in execution time exhibited in reactive and self-initiated movements.

Method

Karate practitioners and no-karate practitioners were compared performing a reverse punch in reaction to an external stimulus or following the intention to produce a response (self-initiated). The task was completed following the presentation of a specific (i.e., life-size image of opponent) or general stimulus and in the presence of click trains or white noise.

Results

Kinematic analyses indicated reactive movement had shorter time to peak velocity and movement time, as well as greater accuracy than self-initiated movement. These differences were independent of participant skill level although peak velocity was higher in the karate practice group than in the no-karate practice group. Reaction time (RT) of skilled participants was facilitated by a specific stimulus. There was no effect on RT or kinematic variables of the different type of auditory cues.

Conclusions

The results of this study indicate that asymmetry in execution time of reactive and self-initiated movement holds irrespective of within-task expertise and stimulus specificity. This could have implications for training of sports and/or relearning of tasks that require rapid and accurate movements to intercept/contact a target.  相似文献   

4.
Abstract

The purpose of this study was to compare reaction time (RT) and fractionated RT components (premotor and motor times) between normal and postcontraction conditions. Twelve participants performed 20 trials each of control and postcontraction RT conditions. For the control condition, participants executed a learned, rapid, knee-extension contraction response to an auditory stimulus. The postcontraction condition was identical to the control condition except that the participants performed a 3-s isometric contraction of the knee extensor muscles prior to an auditory stimulus. Muscle activity was recorded from the quadriceps muscle group. Results indicated that the postcontraction condition was significantly faster than the control condition for the average RT, premotor time, and motor time. It was concluded that reaction time, processing time, and muscle contraction time for a learned task could be significantly reduced following an isometric contraction.  相似文献   

5.
The purpose of this study was to compare reaction time (RT) and fractionated RT components (premotor and motor times) between normal and postcontraction conditions. Twelve participants performed 20 trials each of control and postcontraction RT conditions. For the control condition, participants executed a learned, rapid, knee-extension contraction response to an auditory stimulus. The postcontraction condition was identical to the control condition except that the participants performed a 3-s isometric contraction of the knee extensor muscles prior to an auditory stimulus. Muscle activity was recorded from the quadriceps muscle group. Results indicated that the postcontraction condition was significantly faster than the control condition for the average RT, premotor time, and motor time. It was concluded that reaction time, processing time, and muscle contraction time for a learned task could be significantly reduced following an isometric contraction.  相似文献   

6.
The 100 ms ruling for false start disqualification at athletic competitions governed by the International Association of Athletics Federations has been in force since the early 1990s. Throughout this period, there have been marked changes to the rules that govern the disqualification of athletes from sprint events incorporating starts from blocks. This study analysed all available World and European Championship response-time (RT) data from 1999 to 2014 to examine effects of rule changes on competition RT at major championships. The exponentially modified Gaussian distribution was used to model RT and make comparisons relative to athletes’ sex, ruling periods and competition rounds. Revised RT thresholds of 115 ms and 119 ms were identified for men and women, respectively, indicating that the current 100 ms rule could result in some false starts not being detected in competitive athletics. The study proposes that when using existing International Association of Athletics Federations approved systems, the false start detection threshold should be increased and that men and women athletes should have different thresholds because of substantial evidence of a sex-based difference in RT in elite-standard athletes.  相似文献   

7.
Abstract

When the response movements are as short and simple as possible, the time lag between stimulus and response for one movement is shortened by introducing the stimulus for a second movement during the latent period for the first (usually about .22 sec). Under these conditions the latent period of the second movement is increased about 25 percent. This does not seem to be caused by true psychological refractoriness, since ability to accept the second stimulus and respond to it is still present. A control experiment furnishes evidence that it is probably a foreperiod-expectancy phenomenon. The length of the response latency of a simple single movement is increased about 40 percent if conditions are altered so that a second stimulus requiring a second movement is expected some time within a half-second after the first stimulus. All of these results are consistent with the recent memory drum theory of neuromotor response.  相似文献   

8.
Abstract

The present study sought to determine whether individuals could be trained to attenuate the visual dominance effect by selecting a proprioceptive stimulus for attention. Using a reaction time (RT) task, subjects received either: (a) visual (V), (b) proprioceptive (P), or (c) combined V and P (VP) stimuli during the first four days. Each subject was then tested under all three stimuli conditions. Results showed that reaction time to the P cue was always faster than that to V or combined VP stimuli. The order in which subjects were tested under each stimulus modality significantly affected the results such that those subjects who received initial exposure to the V stimulus produced the slowest premotor time scores but the fastest motor time scores. These results suggest that the nature of the stimulus which initiates the volitional task can affect both the central processing requirements to initiate the response, and the qualitative manner in which the motor command is executed.  相似文献   

9.
Abstract

The force enhancement of muscle twitch contraction after a maximal voluntary contraction (MVC) has been defined as post-activation potentiation. However, the effects of post-activation potentiation on ballistic movements have not been studied extensively, or the underlying neurophysiologycal mechanism. In the current study, we examined post-activation potentiation and spinal H-reflex excitability in the soleus muscle. Mechanical power during explosive ballistic plantar flexions was measured in 14 males before and after 5 s, 4 min, and 10 min of isometric conditioning (EPFpre, EPF5s, EPF4min, EPF10min, respectively). Four sessions corresponding to four different protocols of isometric conditioning were conducted. The protocols were different in the intensity (10% vs. 100% of MVC) and duration (7 vs. 10 s) of the isometric conditioning. The results showed a significant enhancement in mechanical power in EPF4min compared with EPFpre, only when the isometric conditioning was performed at 100% of MVC for 10 s. No significant changes were observed in the H-related parameters (e.g amplitude, threshold, H/M ratio) after the isometric conditioning. Our results show that to obtain a post-activation potentiation during explosive ballistic movements, the intensity and duration of the isometric conditioning must be controlled. Moreover, the improvement in mechanical power is not related to spinal H-reflex excitability.  相似文献   

10.
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   

11.
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   

12.
Purpose:The aim of the study was to determine whether corticospinal excitability and inhibition of the tibialis anterior during single-leg standing differs among individuals with chronic ankle instability(CAI),lateral ankle sprain copers,and healthy controls.Methods:Twenty-three participants with CAI,23 lateral ankle sprain copers,and 24 healthy control participants volunteered.Active motor threshold(AMT),normalized motor-evoked potential(MEP),and cortical silent period(CSP)were evaluated by transcranial magnetic stimulation while participants performed a single-leg standing task.Results:Participants with CAI had significantly longer CSP at 100%of AMT and lower normalized MEP at 120%of AMT compared to lateral ankle sprain copers(CSP100%:p=0.003;MEP120%:p=0.044)and controls(CSP100%:p=0.041;MEP120%:p=0.006).Conclusion:This investigation demonstrate altered corticospinal excitability and inhibition of the tibialis anterior during single-leg standing in participants with CAI.Further research is needed to examine the effects of corticospinal maladaptations to motor control of the tibial anterior on postural control performance in those with CAI.  相似文献   

13.

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 motor pattern 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 by feedback frequency during practice that affects parameter learning but not pattern learning.  相似文献   

14.
Abstract

This study investigated the effects of sex and athletic status on reaction latencies and movement time. One hundred subjects, categorized into five groups of 20 subjects each—male athletes (MA), female athletes (FA), male nonathletes (MNA), female nonathletes (FNA), and control group (CG)—were tested over a period of five consecutive days. Several different types of incentives were used to ensure that subjects provided the fastest times possible. Two blocks of 25 trials were administered to each subject on each day. A 2 × 2 × 2 × 5 × 2 mixed factorial analysis of variance was used to test for between-subject differences of group (experimental/control), sex, and athletic status and for within-subject differences of days and blocks. The four dependent variables were reaction time (RT) mean, RT consistency, movement time (MT) mean, and MT consistency. Results did not support the classic finding of male superiority over females in RT/MT or athletes' superiority over nonathletes. Evidence of athletic superiority emerged, but for the first day of practice only. As subjects were allowed extended practice over a 5-day test period in which knowledge of results (KR) and other incentives were provided, differences in the experimental groups disappeared. Sex was the predominant factor in consistency, with males being less variable in RT (p = .02) performance than females. There were no sex differences in MT consistency.  相似文献   

15.
Objective: The acute responses to resistance training (RT) between males and females are poorly understood, especially from a neural perspective. Therefore, we aimed to compare the corticospinal and intracortical responses during fatigue and recovery following RT.

Methods: Twenty-two participants (12M, 10F) completed one-session of RT (3?×?12 repetition maximum) unilateral leg extensions with 60?s recovery. Single- and paired-pulse transcranial magnetic stimulation measured changes in the motor-evoked potential (MEP), corticospinal silent period (CSP), CSP/MEP ratio, and intracortical facilitation/inhibition (ICF, SICI). The maximal compound wave (MMAX) measured peripheral excitability of the rectus femoris (RF) and maximal voluntary isometric contraction (MVIC) neuromuscular function of the leg extensors. Measures were taken immediately post, 30?min, 1 and 6?h post-training.

Results: A significantly greater increase in MEP/MMAX ratio (p?=?.005) was observed for females immediately post-training compared to males. While no sex differences in MEP/MMAX ratio was observed at 30?min and 1?h post-training, a greater MEP/MMAX ratio for males was observed at 30?min (p?p?=?.003). CSP trended to decrease for males compared to females immediately post-training (d?=?1.93). MVIC was decreased post-training for males; 14.22% and females; 14.16% (P?MAX reduced at 30?min for both groups (P?P?>?.05).

Conclusion: The net output of corticospinal excitability is similar between males and females during fatigue. However, the mechanism in which this is modulated (increased MEP, decreased CSP) appears to be sex-specific.  相似文献   

16.
Abstract

This study examined the effects of knowledge of results (KR) delay and subjective estimation of movement form on the acquisition and retention of a motor skill. During acquisition, four groups of participants performed 60 trials of a throwing accuracy task under the following conditions: (a) immediate KR, (b) delayed KR, (c) immediate KR + form estimation, and (d) delayed KR + form estimation. Retention tests of throwing accuracy and outcome error estimation in the absence of visual KR were administered 5 min and 24 hours following acquisition. Throwing accuracy was significantly higher during acquisition but significantly lower during retention for immediate-KR participants than for delayed-KR participants. However, participants who estimated their movement form during acquisition produced significantly higher throwing accuracy and lower estimation error during retention than those who did not.  相似文献   

17.
Applying the Go/No-Go paradigm to fencing, we investigated the relationship between the moment at which the No-Go signal appeared after a movement had been initiated and the time required by fencers to suppress the motor execution of a step-lunge. Secondarily, we determined a time threshold from which movement inhibition results in an error. The No-Go stimulus was represented by a real attack movement. 18 elite fencers and a fencing master were included in the study. Four force plates measured the horizontal components of the fencer's and master's reaction forces, which were used to calculate the time components of the attack and the response inhibition process. Also, the velocity and displacement of the master's and fencer's respective centres of mass were estimated using inverse dynamics. In all cases, cognitive inhibition processes were completed after the onset of movement. Movement time was calculated using four time components (muscle activation, muscle deactivation, transition and braking time). The results obtained revealed that cognitive processes were not significantly affected by the timing of the appearance of the No-Go signal. In contrast, movement time and its time components tended to decrease when the time delay between the No-Go stimulus and the onset of the fencer's movement increased. In conclusion, any attempt to withhold an attack movement when it has already started leads to an error that increases the risk of being hit by the opponent, especially when attack is inhibited within 150?ms after the movement has started.  相似文献   

18.
Abstract

The developmental nature of reaction time (RT) and anticipation timing (AT) performance, as well as the relationship between them, was investigated using 15 male and 15 female subjects at each of five age levels—7, 9, 11, 13, and 20 yrs. Each subject was given 40 trials for both RT and AT performance with task order counterbalanced. Results indicated that as age increased RT decreased, with males having more rapid RT than females. The two younger age groups differed from the three older groups on AT performance. RT was significantly correlated with AT (|CE| measure) for the 7, 9, and 11 yr old males but not in any other age by gender condition. Apparently neither young males nor young females have a good motor plan in memory to control AT performance. However, the more rapid RT (and thus better response initiation) of the males allows better AT performance at the younger ages. Beginning about 10–11 yrs of age, better motor plans are developed in children's memory system, leading to less reliance on rapid RT for good AT performance, and thus the correlation between RT and AT performance is not present.  相似文献   

19.
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   

20.
Abstract

This study was undertaken to investigate relationships between various forms of creativity, and to determine whether the expression of motor creativity is related to selected motor skills. The tests administered to the 65 fourth grade subjects consisted of creative thinking tests, a motor creativity battery, and motor skill tests. The following conclusions were drawn: (a) the expression of motor creativity through movement is not related to performance on the selected motor skill items; (b) creativity does not appear to be a generalized trait in as much as significant relationships were not found between the various aspects of creativity; (c) a tendency toward generalization of creativity was found for girls but not for boys; (d) a combination of weight, figural fluency and figural originality accounts for a significant amount of the variability in motor creativity for boys, while a combination of figural and verbal creativity factors does the same for girls; (e) boys of this age perform significantly better than girls on skill tests involving strength, while girls excel on balance and agility items.  相似文献   

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