Reaction Time and Intent to Respond

1966 ◽  
Vol 23 (3_suppl) ◽  
pp. 1108-1110
Author(s):  
Roy Yensen
Keyword(s):  
Reaction Time ◽  
Movement Time ◽  
Muscle Tension ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Prime Movers

It is suggested that increases in muscle tension may have occurred just prior to the initiation of the response under conditions of artificially increased mass and that these may have contributed to Whitley's (1966) finding of significantly faster RT under this condition. Following brief discussion of variation in intent to move more or less strongly, it is postulated that the exertion of near maximum voluntary contraction of the prime movers in the initiation of a movement would decrease the RT and that such RT would correlate positively with movement time.

Noise and muscle contraction affecting vigilance task performance

2005 ◽  
Vol 4 (3) ◽  
pp. 157-171
Author(s):  
Duane C. Button ◽  
David G. Behm ◽  
Michael Holmes ◽  
Scott N. Mackinnon
Keyword(s):  
Reaction Time ◽  
Muscle Contraction ◽  
Task Performance ◽  
Video Game ◽  
Movement Time ◽  
Maximum Voluntary Contraction ◽  
Vigilance Task ◽  
Voluntary Contraction ◽  
Neuromuscular Fatigue ◽  
Muscle Contraction Intensity

The objective of this study was to determine the effects of muscle contraction intensity, neuromuscular fatigue, and noise on vigilance performance. Dependent variables included simple (reaction time and movement time) and complex (video game: Tetris) vigilance tasks (SVT and CVT respectively) and maximum voluntary contraction (MVC) force and activation. Vigilance tasks and MVC were randomly allocated to 5 minute blocks during a pre-test. Following the pre-test, the tests were again randomly allocated within three, 15 minute testing sessions over 65 minutes, while 1) being exposed to high (95 dB (A)) or low (53 dB (A)) levels of noise, and 2) performing muscle contractions at 20% and 5% of MVC, or no contractions. Ninety-five (95) dB (A) noise increased (p ≤ 0.01) SVT (reaction time and movement time combined) by 11.2% and decreased (p ≤ 0.01) CVT by 20%. Both 20% and 5% MVC impaired SVT and CVT to a similar extent, while no changes were seen with no contractions. Furthermore, neuromuscular fatigue had no apparent effect on vigilance task performance. These findings suggest that the distraction of noise and divided attention between muscle contraction and a vigilance task decreases performance.

scholarly journals Motor planning perturbation: muscle activation and reaction time

2018 ◽  
Vol 120 (4) ◽  
pp. 2059-2065
Author(s):  
Stefan Delmas ◽  
Agostina Casamento-Moran ◽  
Seoung Hoon Park ◽  
Basma Yacoubi ◽  
Evangelos A. Christou
Keyword(s):  
Reaction Time ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Maximum Voluntary Contraction ◽  
Motor Planning ◽  
Reaction Time Task ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Time Interval ◽  
Voluntary Activity

Reaction time (RT) is the time interval between the appearance of a stimulus and initiation of a motor response. Within RT, two processes occur, selection of motor goals and motor planning. An unresolved question is whether perturbation to the motor planning component of RT slows the response and alters the voluntary activation of muscle. The purpose of this study was to determine how the modulation of muscle activity during an RT response changes with motor plan perturbation. Twenty-four young adults (20.5 ±1.1 yr, 13 women) performed 15 trials of an isometric RT task with ankle dorsiflexion using a sinusoidal anticipatory strategy (10–20% maximum voluntary contraction). We compared the processing part of the RT and modulation of muscle activity from 10 to 60 Hz of the tibialis anterior (primary agonist) when the stimulus appeared at the trough or at the peak of the sinusoidal task. We found that RT ( P = 0.003) was longer when the stimulus occurred at the peak compared with the trough. During the time of the reaction, the electromyography (EMG) power from 10 to 35 Hz was less at the peak than the trough ( P = 0.019), whereas the EMG power from 35 to 60 Hz was similar between the peak and trough ( P = 0.92). These results suggest that perturbation to motor planning lengthens the processing part of RT and alters the voluntary activation of the muscle by decreasing the relative amount of power from 10 to 35 Hz. NEW & NOTEWORTHY We aimed to determine whether perturbation to motor planning would alter the speed and muscle activity of the response. We compared trials when a stimulus appeared at the peak or trough of an oscillatory reaction time task. When the stimulus occurred at the trough, participants responded faster, with greater force, and less EMG power from 10-35 Hz. We provide evidence that motor planning perturbation slows the response and alters the voluntary activity of the muscle.

Muscle Strength Assessment from the EMG Frequency Spectrum

1987 ◽  
Vol 31 (3) ◽  
pp. 310-314 ◽  
Author(s):  
Eui S. Jung
Keyword(s):  
Biceps Brachii ◽  
Muscle Tension ◽  
Maximum Voluntary Contraction ◽  
Power Spectra ◽  
Voluntary Contraction ◽  
The Other ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Strength Assessment ◽  
The Right

Assessment of a worker's strength is of great interest when evaluating the worker's ability to safely perform a job. Many previous studies have shown that surface electromyogram EMG amplitudes correlate well with muscle force. The present study furthered this concept by using EMG power spectra to achieve a quantified representation of true strength capability. Two groups of male subjects performed isometric elbow flexions while EMG was obtained from the right belly of biceps brachii. One group exercised their arms regularly while the other not. Six different levels of graded maximum voluntary contraction (%MVC) were selected to examine the relations between muscle tension and the mean power frequency (MPF) resulting from EMG power spectra. Resultant MPF's ranged between 50Hz and 70Hz in agreement with previous research results. Two-way ANOVA showed that, in the trained group, a significant increase in the MPF was found at near maximum contractions, whereas the other group failed to show any difference. Further analysis revealed that this increase in MPF was mainly caused by the power increase in the higher bandwidth (70—100Hz). A significant variation between subjects in both groups was also observed.

scholarly journals The Effect of Mechanical Vibration Stimulation of Perception Subthreshold on the Muscle Force and Muscle Reaction Time of Lower Leg

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Huigyun Kim ◽  
Kiyoung Kwak ◽  
Dongwook Kim
Keyword(s):  
Reaction Time ◽  
Vibration Frequency ◽  
Muscle Force ◽  
Maximum Voluntary Contraction ◽  
Mechanical Vibration ◽  
Lower Leg ◽  
Voluntary Contraction ◽  
Perception Threshold ◽  
Measurement Results ◽  
Analysis System

The objective of this study is to investigate the effect of mechanical vibration stimulation on the muscle force and muscle reaction time of lower leg according to perception threshold and vibration frequency. A vibration stimulation with perception threshold intensity was applied on the Achilles tendon and tibialis anterior tendon. EMG measurement and analysis system were used to analyze the change of muscle force and muscle reaction time according to perception threshold and vibration frequency. A root-mean-square (RMS) value was extracted using analysis software and Maximum Voluntary Contraction (MVC) and Premotor Time (PMT) were analyzed. The measurement results showed that perception threshold was different from application sites of vibration frequency. Also, the muscle force and muscle reaction time showed difference according to the presence of vibration, frequency, and intensity. This result means that the vibration stimulation causes the change on the muscle force and muscle reaction time and affects the muscles of lower leg by the characteristics of vibration stimulation.

Muscle Fatigue Induced by Sustained Isometric Contraction

1973 ◽  
Vol 15 (1) ◽  
pp. 67-73
Author(s):  
Noorallah V. Gillani ◽  
Dhanjoo N. Ghista
Keyword(s):  
Muscle Fatigue ◽  
Isometric Contraction ◽  
Muscle Tension ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Thermodynamic Criterion ◽  
Static Contraction ◽  
Static Effort ◽  
Suitable Measure ◽  
Regional Metabolism

An important potential thermodynamic criterion for the condition of muscle fatigue induced by a single sustained isometric contraction is discussed, and a method is suggested for its use in determining the duration for which any given static contraction will be sustained before the condition of fatigue is reached. In a healthy rested muscle, under given environmental conditions, the production of a critical amount of heat caused by local regional metabolism is postulated as a necessary response to sustained static effort beyond 15% MVC before fatigue can occur. Muscle response is expressed here as a percent of maximum voluntary contraction (% MVC), a relative unit for each group of muscles which is a suitable measure of the actual level of physiological stimulus for any muscle. A relation between static muscle tension, the duration for which such a tension is sustained, and the critical amount of heat produced until the onset of fatigue is derived. It is assumed that the amount of heat liberated in the muscle during regional metabolism can be measured.

Whole-Body Reaching Movements Formulated by Minimum Muscle-Tension Change Criterion

2016 ◽  
Vol 28 (5) ◽  
pp. 950-969 ◽  
Author(s):  
Naoki Kudo ◽  
Kyuheong Choi ◽  
Takahiro Kagawa ◽  
Yoji Uno
Keyword(s):  
Muscle Tension ◽  
Maximum Voluntary Contraction ◽  
Weighting Factor ◽  
Voluntary Contraction ◽  
The Body ◽  
Joint Torque ◽  
Reaching Movements ◽  
Whole Body ◽  
Hand Position ◽  
Tension Change

It is well known that planar reaching movements of the human shoulder and elbow joints have invariant features: roughly straight hand paths and bell-shaped velocity profiles. The optimal control models with the criteria of smoothness or precision, which determine a unique movement pattern, predict such features of hand trajectories. In this letter on expanding the research on simple arm reaching movements, we examine whether the smoothness criteria can be applied to whole-body reaching movements with many degrees of freedom. Determining a suitable joint trajectory in the whole-body reaching movement corresponds to the optimization problem with constraints, since body balance must be maintained during a motion task. First, we measured human joint trajectories and ground reaction forces during whole-body reaching movements, and confirmed that subjects formed similar movements with common characteristics in the trajectories of the hand position and body center of mass. Second, we calculated the optimal trajectories according to the criteria of torque and muscle-tension smoothness. While the minimum torque change trajectories were not consistent with the experimental data, the minimum muscle-tension change model was able to predict the stereotyped features of the measured trajectories. To explore the dominant effects of the extension from the torque change to the muscle-tension change, we introduced a weighted torque change cost function. Considering the maximum voluntary contraction (MVC) force of the muscle as the weighting factor of each joint torque, we formulated the weighted torque change cost as a simplified version of the minimum muscle-tension change cost. The trajectories owing to the minimum weighted torque change criterion also showed qualitative agreement with the common features of the measured data. Proper estimation of the MVC forces in the body joints is essential to reproduce human whole-body movements according to the minimum muscle-tension change criterion.

scholarly journals Effects of Static and Dynamic Stretching on Force Sense, Dynamic Flexibility and Reaction Time of Children

2019 ◽  
Vol 12 (1) ◽  
pp. 22-27
Author(s):  
Dimitris Chatzopoulos ◽  
Georgios Doganis ◽  
Georgios Lykesas ◽  
Nikolaos Koutlianos ◽  
Christos Galazoulas ◽  
...  
Keyword(s):  
Reaction Time ◽  
Repeated Measures ◽  
Movement Time ◽  
Young Male ◽  
Voluntary Contraction ◽  
Warm Up ◽  
Dynamic Stretching ◽  
Force Matching ◽  
Matching Test ◽  
Force Sense

Background: Traditionally, stretching protocols are basic components of warm-up aiming to improve performance and reduce injuries. However, the literature suggests that different stretching protocols during warm-up may have diverse effects on performance. Objective: The purpose of this study was to compare the acute effects of three different stretching protocols on force sense, dynamic flexibility, reaction time and movement time. Methods: The study included twenty-five participants who were TaeKwonDo young male players (age = 11.78 ± 1.66 years.). All the participants performed one of the following protocols on different days: (a) 5 min jogging followed by 3 min Static Stretching (SS), (b) 5 min jogging followed by 3 min Dynamic Stretching (DS), and (c) 5 min jogging followed by 3 min of rest (NS). After the protocols, the participants performed the following measurements: (a) force-matching test at 20% maximal isometric voluntary contraction (force sense), (b) active straight leg raise test (dynamic flexibility) and (c) reaction and movement time test. Results: Repeated measures analysis of variance revealed no significant main effects on force sense. Furthermore, SS performed significantly better in dynamic flexibility in comparison to NS, and DS performed significantly better in terms of dynamic flexibility and movement time compared to SS. Conclusion: According to the results of the study, it seems that force sense is not affected by either SS or DS protocols (30 sec duration per muscle group). Moreover, it seems that DS in the warm-up is more appropriate than SS for activities requiring dynamic flexibility and movement time.

scholarly journals Development of a trunk motor paradigm for use in neuroimaging

2020 ◽  
Vol 11 (1) ◽  
pp. 193-200
Author(s):  
Elizabeth Saunders ◽  
Brian C. Clark ◽  
Leatha A. Clark ◽  
Dustin R. Grooms
Keyword(s):  
Motor Control ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Erector Spinae ◽  
Head Motion ◽  
Low Back ◽  
Cyclic Contraction ◽  
Cyclic Contractions ◽  
Measurement Units ◽  
Healthy Participants

AbstractThe purpose of this study was to quantify head motion between isometric erector spinae (ES) contraction strategies, paradigms, and intensities in the development of a neuroimaging protocol for the study of neural activity associated with trunk motor control in individuals with low back pain. Ten healthy participants completed two contraction strategies; (1) a supine upper spine (US) press and (2) a supine lower extremity (LE) press. Each contraction strategy was performed at electromyographic (EMG) contraction intensities of 30, 40, 50, and 60% of an individually determined maximum voluntary contraction (MVC) (±10% range for each respective intensity) with real-time, EMG biofeedback. A cyclic contraction paradigm was performed at 30% of MVC with US and LE contraction strategies. Inertial measurement units (IMUs) quantified head motion to determine the viability of each paradigm for neuroimaging. US vs LE hold contractions induced no differences in head motion. Hold contractions elicited significantly less head motion relative to cyclic contractions. Contraction intensity increased head motion in a linear fashion with 30% MVC having the least head motion and 60% the highest. The LE hold contraction strategy, below 50% MVC, was found to be the most viable trunk motor control neuroimaging paradigm.

scholarly journals The Effects of Spinal Manipulation on Motor Unit Behavior

2021 ◽  
Vol 11 (1) ◽  
pp. 105
Author(s):  
Lucien Robinault ◽  
Aleš Holobar ◽  
Sylvain Crémoux ◽  
Usman Rashid ◽  
Imran Khan Niazi ◽  
...  
Keyword(s):  
Motor Unit ◽  
Conduction Velocity ◽  
Spinal Manipulation ◽  
Maximum Voluntary Contraction ◽  
Force Production ◽  
Movement Control ◽  
Position Sense ◽  
Joint Position Sense ◽  
Voluntary Contraction ◽  
Passive Movement

Over recent years, a growing body of research has highlighted the neural plastic effects of spinal manipulation on the central nervous system. Recently, it has been shown that spinal manipulation improved outcomes, such as maximum voluntary force and limb joint position sense, reflecting improved sensorimotor integration and processing. This study aimed to further evaluate how spinal manipulation can alter neuromuscular activity. High density electromyography (HD sEMG) signals from the tibialis anterior were recorded and decomposed in order to study motor unit changes in 14 subjects following spinal manipulation or a passive movement control session in a crossover study design. Participants were asked to produce ankle dorsiflexion at two force levels, 5% and 10% of maximum voluntary contraction (MVC), following two different patterns of force production (“ramp” and “ramp and maintain”). A significant decrease in the conduction velocity (p = 0.01) was observed during the “ramp and maintain” condition at 5% MVC after spinal manipulation. A decrease in conduction velocity suggests that spinal manipulation alters motor unit recruitment patterns with an increased recruitment of lower threshold, lower twitch torque motor units.

Relationship of Reaction Time and Movement Time in a Gross Motor Skill

1973 ◽  
Vol 36 (2) ◽  
pp. 453-454 ◽  
Author(s):  
Richard Groves
Keyword(s):  
Reaction Time ◽  
Motor Skill ◽  
Movement Time ◽  
Gross Motor ◽  
Moment Coefficient ◽  
Relationship Of ◽  
Gross Motor Skill

The purpose of the study was to investigate the independence of reaction time (RT) and movement time (MT) in a gross motor skill, the racing start in swimming. RT and MT were quantified for each S by counting frames of film for five trials. The Pearson product-moment coefficient of –.231 ( p > .05) between means indicated that RT and MT were independent factors.

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