Temporal Pattern of Agonist-Antagonist EMG Activity during Rapid Limb Movements in Man

1987 ◽  
Vol 65 (3) ◽  
pp. 933-934
Author(s):  
Jay H. Williams ◽  
William S. Barnes
Keyword(s):  
Temporal Pattern ◽  
Emg Activity ◽  
Maximal Velocity ◽  
Elbow Extension ◽  
Limb Movements ◽  
Movement Velocity ◽  
Braking Force ◽  
Positive Correlations

Analysis of elbow-extension movements, executed at maximal velocity, show positive correlations of timing of agonist-antagonist EMG activity with both movement velocity and displacement. Results indirectly support the notion that the antagonist musculature provides a braking force to arrest rapid limb movements.

Changes in the Temporal Pattern of Primary Motor Cortex Activity in a Directional Isometric Force Versus Limb Movement Task

1998 ◽  
Vol 80 (3) ◽  
pp. 1577-1583 ◽  
Author(s):  
Lauren E. Sergio ◽  
John F. Kalaska
Keyword(s):  
Motor Cortex ◽  
Temporal Pattern ◽  
Primary Motor Cortex ◽  
Isometric Force ◽  
Limb Movement ◽  
Emg Activity ◽  
Limb Movements ◽  
Hand Motion ◽  
Burst Pattern ◽  
Spatial Coordinates

Sergio, Lauren E. and John F. Kalaska. Changes in the temporal pattern of primary motor cortex activity in a directional isometric force versus limb movement task. J. Neurophysiol. 80: 1577–1583, 1998. We recorded the activity of 75 proximal-arm-related cells in caudal primary motor cortex (MI) while a monkey generated either isometric forces or limb movements against an inertial load. The forces and movements were in eight directions in a horizontal plane. The isometric force generated at the hand increased monotonically in the direction of the target force level. The force exerted against the load in the movement task was more complex, including a transient decelerative phase during the movement as the hand approached the target. Electromyographic (EMG) activity of proximal-arm muscles reflected the task-dependent changes in dynamics, showing a ramp increase in activity during the isometric task and a reciprocal triphasic burst pattern in the movement task. A sliding 50-ms window analysis showed that the directionality of the EMG, when expressed in hand-centered spatial coordinates, remained stable throughout the isometric ramp but often showed a significant transient shift during the limb movements. Many cells in M1 showed corresponding significant changes in activity pattern and instantaneous directionality between the two tasks. This momentary dissociation of discharge from the directional kinematics of hand displacement is evidence that the activity of many single proximal-arm related M1 cells is not coupled only to the direction and velocity of hand motion.

Changes in motor unit recruitment thresholds of the human anconeus muscle during torque development preceding shortening elbow extensions

2012 ◽  
Vol 107 (10) ◽  
pp. 2876-2884 ◽  
Author(s):  
B. Harwood ◽  
C. L. Rice
Keyword(s):  
Motor Unit ◽  
Discharge Rate ◽  
Maximal Velocity ◽  
Elbow Extension ◽  
Movement Velocity ◽  
Maximal Voluntary Isometric Contraction ◽  
Resultant Velocity ◽  
Constant Resistance ◽  
Torque Development ◽  
Shortening Contractions

Rate of torque development and the subsequent movement velocity are modulated by motor unit (MU) properties, primarily MU discharge rate and MU recruitment threshold (MURT). In isometric conditions, MURTs have been shown to decrease with increased rates of torque development. It is unclear whether this relationship is similar in the production of dynamic shortening contractions. Using fast joint velocities to drive the system, we aimed to determine how anconeus MURTs recorded during the torque production phase preceding movement were affected in relation to the resultant peak elbow extension velocity. Recruitment thresholds of 17 MUs from 9 young men were tracked throughout non-isokinetic dynamic elbow extensions with velocities ranging from 64°/s to 500°/s at a constant resistance of 25% of maximal voluntary isometric contraction and during isometric elbow extensions (0°/s). Relative MURTs decreased ∼50% from the slowest (<25% of maximal velocity) to the fastest (>75% of maximal velocity) resultant velocity ranges ( P < 0.05). Although a significant ( P < 0.001) but weak ( r = −0.27, R2 = 0.08) relationship was observed between MURT and resultant peak elbow extension velocity for the group, only 7 of the 17 MUs displayed significant moderate ( r = −0.40, R2 = 0.17) to strong ( r = −0.85, R2 = 0.73) negative MURT-velocity relationships. These data indicate variable responses of MURTs with increasing resultant peak velocity, which may be related to the intrinsic properties of individual MUs.

Mind-Muscle Connection: Verbal Instructions Alter Electromyographic Activity for Elbow Flexors and Extensors During Co-Contraction Training

2020 ◽  
pp. 003151252094908
Author(s):  
Rafael A. Fujita ◽  
Marina M. Villalba ◽  
Nilson R. S. Silva ◽  
Matheus M. Pacheco ◽  
Matheus M. Gomes
Keyword(s):  
Strength Training ◽  
Elbow Joint ◽  
Biceps Brachii ◽  
Elbow Flexion ◽  
Emg Activity ◽  
Elbow Extension ◽  
Verbal Instruction ◽  
Triceps Brachii ◽  
Verbal Instructions ◽  
Lateral Head

Co-contraction training has demonstrated similar electromyographic (EMG) activity levels compared to conventional strength training. Since verbal instructions can increase EMG activity on target muscles during conventional exercises, the same should occur during co-contraction. In this study we analyzed whether different verbal instructions would alter the EMG activity of target muscles - biceps brachii (BB) and triceps brachii lateral head (TB) - during co-contraction training for the elbow joint. Seventeen males with experience in strength training performed a co-contraction set in two verbal instruction conditions to emphasize either elbow flexion or elbow extension. Surface electrodes were fixed over biceps brachii and triceps brachii lateral head muscles. We measured EMG mean amplitude and analyzed data with 2-way ANOVA. We found a significant interaction between muscle and verbal instruction ( p = 0.002). Post hoc tests indicated that verbal instructions ( p = 0.001) influenced the BB EMG activity (elbow flexion: M = 68.74, SD = 17.96%; elbow extension: M = 53.47, SD = 16.13%); and also showed difference ( p = 0.006) in the EMG activity between BB and TB with verbal instruction emphasizing the elbow extension (BB: M = 53.47, SD = 16.13%; TB: M = 69.18, SD = 21.79%). There was a difference in the EMG ratio of BB/TB ( p = 0.001) when focusing on elbow flexion ( M = 1.09, SD = 0.30) versus elbow extension ( M = 0.81, SD = 0.25). As verbal instruction modified the magnitude of muscle recruitment during co-contractions for elbow joint muscles, there is a clear mind-muscle connection of importance to this method of training. Also, of importance to trainers, verbal instructions seemed to affect individuals differentially.

The Relative Efficacy of Different forms of Knowledge of Results for the Learning of a New Relative Timing Pattern

2003 ◽  
Vol 56 (4) ◽  
pp. 1-20 ◽  
Author(s):  
Dominique De Jaeger ◽  
Luc Proteau
Keyword(s):  
Temporal Pattern ◽  
Relative Efficacy ◽  
Relative Timing ◽  
Movement Velocity ◽  
Knowledge Of Results ◽  
Timing Pattern ◽  
Verbal Knowledge ◽  
Source Of Information ◽  
Forms Of Knowledge ◽  
Effective Source

The goal of the present study was to determine the relative efficacy of verbal and auditory knowledge of results for promoting learning of a new constrained relative timing pattern. In a series of four experiments we compared the efficiency of verbal knowledge of results to that of auditory knowledge of results. The results of all four experiments revealed that verbal knowledge of result is a very effective source of information to promote learning of a new imposed relative timing pattern. Auditory knowledge of results favoured learning of a new relative timing pattern in a very limited set of circumstances. In the present study, this was only the case when movement velocity remained constant from one segment of the task to the next and if it resulted in an unfamiliar temporal pattern. The results of all four experiments also provided evidence that movement parameterization and relative timing are independent processes that can be developed in parallel.

scholarly journals RADIO-ULNAR PRONATION VS FOREARM EXTENSION: WHICH THE BEST TO REACH THE MAXIMAL BADMINTON RACKET VELOCITY?

2020 ◽  
Vol 20 (2) ◽  
pp. 99-107
Author(s):  
M Phomsoupha ◽  
J Jeuvrey ◽  
G Laffaye
Keyword(s):  
Angular Velocity ◽  
High Speed ◽  
Skill Level ◽  
Maximal Velocity ◽  
Elbow Extension ◽  
End Points ◽  
Head Velocity ◽  
The Difference ◽  
Common Components

Aim. Forearm extension and radio-ulnar pronation are two common components of the final movement during each badminton smash stroke. By coordinating the forearm to produce both extension and pronation at the same time, racket head velocity can be increased. Thus, this study examined maximal velocity and racket deflection during both movements in regard with skill level. Materials and methods. Twenty-two players (8 experts and 14 novices) participated in this study. Wrist, handle and racket head velocity were recorded using high speed cameras (Vicon V8i at a frequency of 250 Hz). Results. The racket head velocity with radio-ulnar pronation was 16 % higher than with forearm extension. This higher velocity resulted from an 8 % higher acceleration and a 70 % higher maximal angular velocity of the end points of the forearm segments during radio-ulnar pronation. In each movement, experts’ maximal velocity was higher than that of novices (p < .001).The maximal velocity of the racket for novices was obtained with elbow extension (20.9 ± 4.8 m/s), with a gain of 47 %, whereas for experts, it was obtained with radio-ulnar pronation (33.9 ± 5.8 m/s), with a gain of 53 %. Conclusion. The difference between the best velocities in both samples is 39 %, obtained respectively by radio-ulnar pronation for experts and an elbow extension for novices. Forearm extension and radio-ulnar pronation acceleration on the handle led to an increase in racket head velocity.

Modification in Movement Accuracy in the Triphasic Pattern during a Rapid Forearm-Flexion Task

1988 ◽  
Vol 67 (2) ◽  
pp. 455-460 ◽  
Author(s):  
Michel André Roy ◽  
Betsy A. Keller ◽  
Pierre P. Lagassé
Keyword(s):  
Movement Time ◽  
Limb Movement ◽  
Emg Activity ◽  
Maximum Speed ◽  
Propulsive Force ◽  
Antagonist Activity ◽  
Movement Velocity ◽  
Movement Accuracy ◽  
Triphasic Pattern

The present study was designed to investigate modifications in the triphasic EMG pattern during a forearm-flexion task at maximum speed which required three levels of movement accuracy. 36 subjects participated in 4 training sessions, performing a total of 200 repetitions of each movement. The fastest movement time was associated with the least accurate movement task. Likewise, the slowest movement time was found for the movement requiring the greatest accuracy. Differences in the duration and amplitude of agonist 1 activity, the start of agonist 2 activity, and the start and amplitude of antagonist activity were observed for the three movements. The results indicate that agonist 1 provides a propulsive force to initiate limb movement. The antagonist EMG activity was thought responsible for braking and correcting limb movement. Modifications in agonist 2 activity suggest this burst is related to movement velocity.

Fluctuations in acceleration during voluntary contractions lead to greater impairment of movement accuracy in old adults

2003 ◽  
Vol 95 (1) ◽  
pp. 373-384 ◽  
Author(s):  
Evangelos A. Christou ◽  
Minoru Shinohara ◽  
Roger M. Enoka
Keyword(s):  
Young Adults ◽  
Eccentric Contractions ◽  
Emg Activity ◽  
Target Velocity ◽  
Movement Velocity ◽  
Movement Accuracy ◽  
Old Adults ◽  
Emg Amplitude ◽  
First Dorsal Interosseus ◽  
Voluntary Contractions

The purpose of the study was to assess the effect of movement velocity on the relation between fluctuations in acceleration and the ability to achieve a target velocity during voluntary contractions performed by young (29.5 ± 4.3 yr) and old (74.9 ± 6.2 yr) adults. Subjects performed concentric and eccentric contractions with the first dorsal interosseus muscle while lifting a submaximal load (15% of maximum) at six movement velocities (0.03–1.16 rad/s). Fluctuations in acceleration, the accuracy of matching the target velocity, and electromyographic (EMG) activity were determined from three trials for each contraction type and movement velocity. The fluctuations in acceleration increased with movement velocity for both concentric and eccentric contractions, but they were greatest during fast eccentric contractions (∼135%) when there was stronger modulation of acceleration in the 5- to 10-Hz bandwidth. Nonetheless, EMG amplitude for first dorsal interosseus increased with movement velocity only for concentric and not eccentric contractions. Consistent with the minimum variance theory, movement accuracy was related to the fluctuations in acceleration for both types of contractions in all subjects. For a given level of fluctuations in acceleration, however, old subjects were three times less accurate than young subjects. Although the EMG amplitude at each speed was similar for young and old adults, only the young adults modulated the power in the EMG spectrum with speed. Thus the fluctuations in acceleration during voluntary contractions had a more pronounced effect on movement accuracy for old adults compared with young adults, probably due to factors that influenced the frequency-domain characteristics of the EMG.

scholarly journals Dopamine-dependent scaling of subthalamic gamma bursts with movement velocity in patients with Parkinson’s disease

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Roxanne Lofredi ◽  
Wolf-Julian Neumann ◽  
Antje Bock ◽  
Andreas Horn ◽  
Julius Huebl ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Symptom Severity ◽  
Maximal Velocity ◽  
Movement Velocity ◽  
Gamma Power ◽  
Highly Correlated ◽  
Cardinal Symptoms ◽  
Deep Brain Stimulation Surgery ◽  
Gamma Burst

Gamma synchronization increases during movement and scales with kinematic parameters. Here, disease-specific characteristics of this synchronization and the dopamine-dependence of its scaling in Parkinson’s disease are investigated. In 16 patients undergoing deep brain stimulation surgery, movements of different velocities revealed that subthalamic gamma power peaked in the sensorimotor part of the subthalamic nucleus, correlated positively with maximal velocity and negatively with symptom severity. These effects relied on movement-related bursts of transient synchrony in the gamma band. The gamma burst rate highly correlated with averaged power, increased gradually with larger movements and correlated with symptom severity. In the dopamine-depleted state, gamma power and burst rate significantly decreased, particularly when peak velocity was slower than ON medication. Burst amplitude and duration were unaffected by the medication state. We propose that insufficient recruitment of fast gamma bursts during movement may underlie bradykinesia as one of the cardinal symptoms in Parkinson’s disease.

Emg and Motor Performance Changes with Practice of a Forearm Movement by Children

1988 ◽  
Vol 67 (2) ◽  
pp. 523-529 ◽  
Author(s):  
Richard Engelhorn
Keyword(s):  
Motor Performance ◽  
Biceps Brachii ◽  
Movement Time ◽  
Age Groups ◽  
Elbow Flexion ◽  
Emg Activity ◽  
Practice Session ◽  
Triceps Brachii ◽  
Movement Velocity ◽  
Time To Peak

The purpose of this research was to investigate changes in the control of movement, using EMG and kinematic variables, over practice by children. Children in three age groups, 7, 9, and 11 yr., performed 60 trials of an elbow-flexion movement. Correct movements consisted of a 60° angular movement of the forearm in 800 msec. The analysis of biceps brachii and triceps brachii muscle EMG activity, movement displacement and timing error, and movement velocity patterns indicated changes in motor performance with practice. All age groups improved performance with practice and also exhibited a decrease in biceps EMG activity with practice. Only movement-time error and time to peak triceps muscle activity differed between the age groups. The 11-yr.-old group significantly altered the timing of the antagonistic response to stop the movement over the practice session. This change is suggested to be related to the greater information-processing ability of these children and the development of appropriate movement strategies to perform the movement task successfully. Other changes observed in the EMG data appear similar to changes observed in studies of adults.

Shaping Appropriate Locomotive Motor Output Through Interlimb Neural Pathway Within Spinal Cord in Humans

2008 ◽  
Vol 99 (6) ◽  
pp. 2946-2955 ◽  
Author(s):  
Noritaka Kawashima ◽  
Daichi Nozaki ◽  
Masaki O. Abe ◽  
Kimitaka Nakazawa
Keyword(s):  
Spinal Cord ◽  
Upper Limb ◽  
Lower Limb ◽  
Muscle Activity ◽  
Swing Phase ◽  
Motor Output ◽  
Emg Activity ◽  
Limb Movements ◽  
Neural Connections ◽  
Upper Limb Movements

Direct evidence supporting the contribution of upper limb motion on the generation of locomotive motor output in humans is still limited. Here, we aimed to examine the effect of upper limb motion on locomotor-like muscle activities in the lower limb in persons with spinal cord injury (SCI). By imposing passive locomotion-like leg movements, all cervical incomplete ( n = 7) and thoracic complete SCI subjects ( n = 5) exhibited locomotor-like muscle activity in their paralyzed soleus muscles. Upper limb movements in thoracic complete SCI subjects did not affect the electromyographic (EMG) pattern of the muscle activities. This is quite natural since neural connections in the spinal cord between regions controlling upper and lower limbs were completely lost in these subjects. On the other hand, in cervical incomplete SCI subjects, in whom such neural connections were at least partially preserved, the locomotor-like muscle activity was significantly affected by passively imposed upper limb movements. Specifically, the upper limb movements generally increased the soleus EMG activity during the backward swing phase, which corresponds to the stance phase in normal gait. Although some subjects showed a reduction of the EMG magnitude when arm motion was imposed, this was still consistent with locomotor-like motor output because the reduction of the EMG occurred during the forward swing phase corresponding to the swing phase. The present results indicate that the neural signal induced by the upper limb movements contributes not merely to enhance but also to shape the lower limb locomotive motor output, possibly through interlimb neural pathways. Such neural interaction between upper and lower limb motions could be an underlying neural mechanism of human bipedal locomotion.

Sign in / Sign up

Export Citation Format

Share Document