Step-Tracking Movements of the Wrist. IV. Muscle Activity Associated With Movements in Different Directions

1999 ◽  
Vol 81 (1) ◽  
pp. 319-333 ◽  
Author(s):  
Donna S. Hoffman ◽  
Peter L. Strick
Keyword(s):  
Muscle Activity ◽  
Human Subjects ◽  
Movement Direction ◽  
Emg Activity ◽  
Gradual Change ◽  
Movement Onset ◽  
Ulnar Deviation ◽  
Flexion Extension ◽  
Tracking Movements ◽  
Movement Curvature

Hoffman, Donna S. and Peter L. Strick. Step-tracking movements of the wrist. IV. Muscle activity associated with movements in different directions. J. Neurophysiol. 81: 319–333, 1999. We examined the patterns of muscle activity associated with multiple directions of step-tracking movements of the wrist in humans and monkeys. Human subjects made wrist movements to 12 different targets that required varying amounts of flexion-extension and radial-ulnar deviation. Wrist muscles displayed two patterns of electromyographic (EMG) modulation as movement direction changed: amplitude graded and temporally shifted. The amplitude-graded pattern was characterized by modulation of the quantity of muscle activity that occurred during two distinct time periods, an agonist burst interval that began before movement onset and an antagonist burst interval that began just after movement onset. The timing of muscle activity over the two intervals showed little variation with changes in movement direction. For some directions of movement, EMG activity was present over both time intervals, resulting in “double bursts.” Modulation of activity during the agonist burst interval was particularly systematic and was well fit by a cosine function. In contrast, the temporally shifted pattern was characterized by a gradual change in the timing of a single burst of muscle activity. The burst occurred at a time intermediate between the agonist and antagonist burst intervals. The temporally shifted pattern was seen less frequently than the amplitude-graded pattern and was present only in selected wrist muscles for specific directions of movement. Monkeys made wrist movements to 8–16 different targets that required varying amounts of flexion-extension and radial-ulnar deviation. These movements were performed more slowly than those of human subjects. The wrist muscles of the monkeys we examined displayed the amplitude-graded pattern of activity but not the temporally shifted pattern. Stimulation of individual wrist muscles in monkeys resulted in wrist movements that were markedly curved, particularly for the wrist extensors. These results indicate that step-tracking movements of the wrist are generated mainly by using the amplitude-graded pattern to modulate muscle activity. We propose that this pattern reflects a central process that decomposes an intended movement into an agonist, “propulsive” component and an antagonist, “braking” component. Separate bursts of muscle activity then are generated to control each component. On the other hand, we argue that the temporally shifted pattern may function to reduce the amount of movement curvature associated with the activation of wrist muscles.

Electromyographic Activity of Trunk Muscles During Flexion-Distraction Treatment of Low Back Patients

1999 ◽  
Author(s):  
Maruti R. Gudavalli ◽  
Jerrilyn A. Backman ◽  
Steven J. Kirstukas ◽  
Anant V. Kadiyala ◽  
Avinash G. Patwardhan ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Erector Spinae ◽  
Trunk Muscles ◽  
Emg Activity ◽  
Electromyographic Activity ◽  
Low Back ◽  
Mean Values ◽  
Flexion Extension ◽  
Left And Right ◽  
The Mean

Abstract The objective of this study was to determine the electromyographic (EMG) activity of the superficial muscles during the treatment of low back patients during a conservative procedure known as the Cox flexion-distraction procedure. A total of 33 low back pain patients were recruited for this study from chiropractic and allopathic orthopedic clinics. EMG signals were collected while the patient was in a prone relaxed position, during the treatment using the flexion-distraction procedure, and during maximum voluntary exertions in the three planes (flexion, extension, left and right lateral bending, and left and right twisting). The mean values of the Root Mean Square (RMS) values of EMG ratios during treatment versus resting indicate that the muscles are active during the treatment. This activity is more than the activity at rest. However the mean values of the RMS EMG ratios (during treatment versus maximum voluntary contraction) are small indicating that the muscle activity during treatment may not influence the treatment loads. The left and right muscles in all muscle groups were similarly active. During the treatment, erector spinae muscles were the most active, followed by the external oblique, and the rectus abdominus muscles. The results from this study provide quantitative data for the muscle activity during the flexion-distraction treatment. This information can be incorporated into computer models to estimate the loads generated during the flexion-distraction treatment due to the muscle activity compared to the loads generated by the chiropractic physician.

Effects of a primary motor cortex lesion on step-tracking movements of the wrist

1995 ◽  
Vol 73 (2) ◽  
pp. 891-895 ◽  
Author(s):  
D. S. Hoffman ◽  
P. L. Strick
Keyword(s):  
Motor Cortex ◽  
Muscle Activity ◽  
Primary Motor Cortex ◽  
Emg Activity ◽  
Wrist Flexion ◽  
Movement Kinematics ◽  
Antagonist Activity ◽  
Cortex Lesion ◽  
Antagonist Muscles ◽  
Tracking Movements

1. We lesioned the contralateral arm area of the primary motor cortex (M1) in a monkey that had been trained to make rapid step-tracking movements of the wrist in different directions. We examined movement kinematics and electromyographic (EMG) activity of forearm muscles both before and 3.5-5 mo after the lesion. 2. The lesion caused marked changes in movement kinematics and the patterns of activity in agonist, synergist, and antagonist muscles. 3. After the lesion, movements to all targets were performed more slowly. In addition, some movements were misdirected. For example, most movements to the target that required wrist flexion and radial deviation were made in two steps, instead of in a single smooth trajectory. 4. After the lesion, distinct bursts of muscle activity were no longer observed during step-tracking movements. In addition, suppression of antagonist activity at movement onset was abolished or reduced. The relative timing of agonist and synergist muscle activity was markedly altered. 5. We conclude that M1 contributes to the precise spatiotemporal patterning of muscle activity during step-tracking movements.

Deficits in Movements of the Wrist Ipsilateral to a Stroke in Hemiparetic Subjects

2004 ◽  
Vol 92 (6) ◽  
pp. 3276-3285 ◽  
Author(s):  
Cherylon A. Yarosh ◽  
Donna S. Hoffman ◽  
Peter L. Strick
Keyword(s):  
Muscle Activity ◽  
Normal Subjects ◽  
Great Difficulty ◽  
Emg Activity ◽  
Temporal Sequencing ◽  
Tracking Movements ◽  
Bilateral Effects ◽  
Age Range ◽  
And Control ◽  
Initial Movement

We examined step-tracking movements of the wrist and associated EMG activity in seven patients (age range, 27–73 yr) and in seven normal subjects that were matched to patients in age, sex, and handedness. All patients exhibited a hemiparesis that resulted from a unilateral cerebrovascular accident (CVA) that included motor areas in the frontal lobe or their efferents. The lesion in three patients was in their dominant hemisphere. The patients were tested 1–48 mo following their CVA. They had great difficulty in performing or were unable to perform step-tracking movements with the contralesional wrist. In addition, the patients displayed striking deficits in wrist movements and muscle activity of the ipsilesional wrist. These movements were >50% slower than those of controls. The initial movement step routinely undershot the target and was only 63% as large as that of controls. The patients made wrist movements with marked directional errors requiring corrective responses. These errors were due largely to inappropriate temporal sequencing of muscle activity. The deficits in movement and muscle activity in the wrist ipsilesional to a CVA were marked, regardless of whether the lesion was in the dominant or nondominant hemisphere. These observations indicate that unilateral lesions can have significant bilateral effects on the generation and control of distal limb movements.

Characteristics of synergic relations during isometric contractions of human elbow muscles

1986 ◽  
Vol 56 (5) ◽  
pp. 1225-1241 ◽  
Author(s):  
T. S. Buchanan ◽  
D. P. Almdale ◽  
J. L. Lewis ◽  
W. Z. Rymer
Keyword(s):  
Human Subjects ◽  
Joint Torque ◽  
Emg Activity ◽  
Triceps Brachii ◽  
Myoelectrical Activity ◽  
Joint Torques ◽  
Flexion Extension ◽  
Premotor Neurons ◽  
Intramuscular Electrodes ◽  
Long Head

We studied the patterns of EMG activity in elbow muscles in three normal human subjects. The myoelectrical activity of 7-10 muscles that act across the human elbow joint was simultaneously recorded with intramuscular electrodes during isometric joint torques exerted over a range of directions. These directions included flexion, extension, varus (internal humeral rotation), valgus (external humeral rotation), and several intermediate directions. The forces developed at the wrist covered a range of 360 degrees, all orthogonal to the long axis of the forearm. The levels of EMG activity were observed to increase with increasing joint torque in an approximately linear manner. All muscles were active for ranges less than 360 degrees and most were active for less than 180 degrees. The EMG activity was observed to vary in a systematic manner with changes in torque direction and, when examined over the full angular range at a variety of torque levels, is simply scaled with increasing torque magnitude. There were no torque directions or torque magnitudes for which a single muscle was observed to be active alone. In all cases, joint torque appeared to be produced by a combination of muscles. The direction for which the EMG of a muscle reached a maximum value was observed to correspond to the direction of greatest mechanical advantage as predicted by a simple mechanical model of the elbow and relevant muscles. Muscles were relatively inactive during varus torques. This implies that the muscles were not acting to stabilize the joint in this direction and could have been allowing ligaments to carry the load. Plots of EMG activity in one muscle against EMG activity in another demonstrate some instances of pure synergies, but patterns of coactivation for most muscles are more complicated and vary with torque direction. The complexity of these patterns raises the possibility that synergies are determined by the task and may have no independent existence. Activity in two heads of triceps brachii (medial head--a single-joint muscle and long head--a two-joint muscle) covaried closely for a range of torque magnitudes and directions, though shoulder torque and hence the forces experienced by the long head of the triceps undoubtedly varied. The similarity of activation patterns indicates that elbow torque was the principal determining factor. The origins of muscle synergies are discussed. It is suggested that they are best understood on the basis of a model which encodes limb torque in premotor neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Strategies for muscle activation during isometric torque generation at the human elbow

1989 ◽  
Vol 62 (6) ◽  
pp. 1201-1212 ◽  
Author(s):  
T. S. Buchanan ◽  
G. P. Rovai ◽  
W. Z. Rymer
Keyword(s):  
Muscle Activation ◽  
Biceps Brachii ◽  
Human Subjects ◽  
Elbow Flexion ◽  
Emg Activity ◽  
Elbow Extension ◽  
Triceps Brachii ◽  
Pronator Teres ◽  
Flexion Extension ◽  
Torque Generation

1. We studied the patterns of electromyographic (EMG) activity in elbow muscles of 14 normal human subjects. The activity of five muscles that act in flexion-extension and forearm supination-pronation was simultaneously recorded during isometric voluntary torque generation, in which torques generated in a plane orthogonal to the long axis of the forearm were voluntarily coupled with torques generated about the long axis of the forearm (i.e., supination-pronation). 2. When forearm supination torques were superimposed on a background of elbow flexion torque, biceps brachii activity increased substantially, as expected; however, brachioradialis and brachialis EMG levels decreased modestly, a less predictable outcome. The pronator teres was also active during pure flexion and flexion coupled with mild supination (even though no pronation torque was required). This was presumably to offset inappropriate torque contributions of other muscles, such as the biceps brachii. 3. When forearm supination torque was superimposed on elbow extension torque, again the biceps brachii was strongly active. The pronator teres also became mildly active during extension with added pronation torque. These changes occurred despite the fact that both the pronator and biceps muscles induce elbow flexion. 4. In these same elbow extension tasks, triceps brachii activity was also modulated with both pronation or supination loads. It was most active during either supination or pronation loads, again despite the fact that it has no mechanical role in producing forearm supination-pronation torque. 5. Recordings of EMG activity during changes in forearm supination-pronation angle demonstrated that activation of the biceps brachii followed classic length-tension predictions, in that less EMG activity was required to achieve a given supination torque when the forearm was pronated (where biceps brachii is relatively longer). On the other hand, EMG activity of the pronator teres did not decrease when the pronator was lengthened. Triceps EMG was also more active when the forearm was supinated, despite its having no direct functional role in this movement. 6. Plots relating EMG activity in biceps brachii, brachialis, and brachioradialis at three different forearm positions revealed that there was a consistent positive near-linear relationship between brachialis and brachioradialis and that biceps brachii is often most active when brachioradialis and brachialis are least active. 7. We argue that, for the human elbow joint at least, fixed muscle synergies are rather uncommon and that relationships between muscle activities are situation dependent.(ABSTRACT TRUNCATED AT 400 WORDS)

Myoelectric Activity Differences in Three Learning Sessions

2002 ◽  
Vol 16 (2) ◽  
pp. 92-96
Author(s):  
Tiina Ritvanen ◽  
Reijo Koskelo ◽  
Osmo H„nninen
Keyword(s):  
High School Students ◽  
Muscle Activity ◽  
Muscle Tension ◽  
Emg Activity ◽  
Traditional Learning ◽  
Myoelectric Activity ◽  
School Students ◽  
Language Laboratory ◽  
Upper Trapezius ◽  
Muscle Groups

Abstract This study follows muscle activity in three different learning sessions (computer, language laboratory, and normal classroom) while students were studying foreign languages. Myoelectric activity was measured in 21 high school students (10 girls, 11 boys, age range 17-20 years) by surface electromyography (sEMG) from the upper trapezius and frontalis muscles during three 45-min sessions. Root mean square (RMS) average from both investigated muscles was calculated. The EMG activity was highest in both muscle groups in the computer-aided session and lowest in the language laboratory. The girls had higher EMG activity in both investigated muscle groups in all three learning situations. The measured blood pressure was highest at the beginning of the sessions, decreased within 10 min, but increased again toward the end of the sessions. Our results indicate that the use of a computer as a teaching-aid evokes more constant muscle activity than the traditional learning situations. Since muscle tension can have adverse health consequences, more research is needed to determine optimal classroom conditions, especially when technical aids are used in teaching.

scholarly journals Rostrocaudal Distribution of the C-Fos-Immunopositive Spinal Network Defined by Muscle Activity during Locomotion

2021 ◽  
Vol 11 (1) ◽  
pp. 69
Author(s):  
Natalia Merkulyeva ◽  
Vsevolod Lyakhovetskii ◽  
Aleksandr Veshchitskii ◽  
Oleg Gorskii ◽  
Pavel Musienko
Keyword(s):  
Spinal Cord ◽  
Locomotor Activity ◽  
Control Systems ◽  
Muscle Activity ◽  
Knee Extensors ◽  
Emg Activity ◽  
Lumbosacral Spinal Cord ◽  
Adductor Muscles ◽  
Spinal Network ◽  
Hip Flexor

The optimization of multisystem neurorehabilitation protocols including electrical spinal cord stimulation and multi-directional tasks training require understanding of underlying circuits mechanisms and distribution of the neuronal network over the spinal cord. In this study we compared the locomotor activity during forward and backward stepping in eighteen adult decerebrated cats. Interneuronal spinal networks responsible for forward and backward stepping were visualized using the C-Fos technique. A bi-modal rostrocaudal distribution of C-Fos-immunopositive neurons over the lumbosacral spinal cord (peaks in the L4/L5 and L6/S1 segments) was revealed. These patterns were compared with motoneuronal pools using Vanderhorst and Holstege scheme; the location of the first peak was correspondent to the motoneurons of the hip flexors and knee extensors, an inter-peak drop was presumably attributed to the motoneurons controlling the adductor muscles. Both were better expressed in cats stepping forward and in parallel, electromyographic (EMG) activity of the hip flexor and knee extensors was higher, while EMG activity of the adductor was lower, during this locomotor mode. On the basis of the present data, which showed greater activity of the adductor muscles and the attributed interneuronal spinal network during backward stepping and according with data about greater demands on postural control systems during backward locomotion, we suppose that the locomotor networks for movements in opposite directions are at least partially different.

Unraveling Interlimb Interactions Underlying Bimanual Coordination

2005 ◽  
Vol 94 (5) ◽  
pp. 3112-3125 ◽  
Author(s):  
Arne Ridderikhoff ◽  
C. (Lieke) E. Peper ◽  
Peter J. Beek
Keyword(s):  
Bimanual Coordination ◽  
Feedforward Control ◽  
Emg Activity ◽  
Minor Role ◽  
Error Corrections ◽  
Flexion Extension ◽  
Contralateral Hand ◽  
Phase Coordination ◽  
The Stability ◽  
Passive Movements

Three sources of interlimb interactions have been postulated to underlie the stability characteristics of bimanual coordination but have never been evaluated in conjunction: integrated timing of feedforward control signals, phase entrainment by contralateral afference, and timing corrections based on the perceived error of relative phase. In this study, the relative contributions of these interactions were discerned through systematic comparisons of five tasks involving rhythmic flexion–extension movements about the wrist, performed bimanually (in-phase and antiphase coordination) or unimanually with or without comparable passive movements of the contralateral hand. The main findings were the following. 1) Contralateral passive movements during unimanual active movements induced phase entrainment to interlimb phasing of either 0° (in-phase) or 180° (antiphase). 2) Entrainment strength increased with the passive movements' amplitude, but was similar for in-phase and antiphase movements. 3) Coordination of unimanual active movements with passive movements of the contralateral hand (kinesthetic tracking) was characterized by similar bilateral EMG activity as observed in active bimanual coordination. 4) During kinesthetic tracking the timing of the movements of the active hand was modulated by afference-based error corrections, which were more pronounced during in-phase coordination. 5) Indications of in-phase coordination being more stable than antiphase coordination were most prominent during active bimanual coordination and marginal during kinesthetic tracking. Together the results indicated that phase entrainment by contralateral afference contributed equally to the stability of in-phase and antiphase coordination, and that differential stability of these patterns depended predominantly on integrated timing of feedforward signals, with only a minor role for afference-based error corrections.

Respiratory Activity of the Rat Posterior Cricoarytenoid Muscle

1997 ◽  
Vol 106 (11) ◽  
pp. 897-901 ◽  
Author(s):  
Robert G. Berkowitz ◽  
John Chalmers ◽  
Qi-Jian Sun ◽  
Paul M. Pilowsky
Keyword(s):  
Phrenic Nerve ◽  
Muscle Activity ◽  
Electrophysiological Study ◽  
Emg Activity ◽  
Diaphragmatic Muscle ◽  
Posterior Cricoarytenoid Muscle ◽  
Inspiratory Activity ◽  
Intramuscular Nerve ◽  
Posterior Cricoarytenoid ◽  
Nerve Discharge

An anatomic and electrophysiological study of the rat posterior cricoarytenoid (PCA) muscle is described. The intramuscular nerve distribution of the PCA branch of the recurrent laryngeal nerve was demonstrated by a modified Sihler's stain. The nerve to the PCA was found to terminate in superior and inferior branches with a distribution that appeared to be confined to the PCA muscle. Electromyography (EMG) recordings of PCA muscle activity in anesthetized rats were obtained under stereotaxic control together with measurement of phrenic nerve discharge. A total of 151 recordings were made in 7 PCA muscles from 4 rats. Phasic inspiratory activity with a waveform similar to that of phrenic nerve discharge was found in 134 recordings, while a biphasic pattern with both inspiratory and post-inspiratory peaks was recorded from random sites within the PCA muscle on 17 occasions. The PCA EMG activity commenced 24.6 ± 2.2 milliseconds (p < .0001) before phrenic nerve discharge. The results are in accord with findings of earlier studies that show that PCA muscle activity commences prior to inspiratory airflow and diaphragmatic muscle activity. The data suggest that PCA and diaphragm motoneurons share common or similar medullary pre-motoneurons. The earlier onset of PCA muscle activity may indicate a role for medullary pre-inspiratory neurons in initiating PCA activity.

scholarly journals Electromyographic Analysis of Traditional and Nontraditional Abdominal Exercises: Implications for Rehabilitation and Training

2006 ◽  
Vol 86 (5) ◽  
pp. 656-671 ◽  
Author(s):  
Rafael F Escamilla ◽  
Eric Babb ◽  
Ryan DeWitt ◽  
Patrick Jew ◽  
Peter Kelleher ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Latissimus Dorsi ◽  
Rectus Femoris ◽  
Rectus Abdominis ◽  
Oblique Muscle ◽  
Emg Activity ◽  
Internal Oblique ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle ◽  
Roll Out

Abstract Background and Purpose. Performing nontraditional abdominal exercises with devices such as abdominal straps, the Power Wheel, and the Ab Revolutionizer has been suggested as a way to activate abdominal and extraneous (nonabdominal) musculature as effectively as more traditional abdominal exercises, such as the crunch and bent-knee sit-up. The purpose of this study was to test the effectiveness of traditional and nontraditional abdominal exercises in activating abdominal and extraneous musculature. Subjects. Twenty-one men and women who were healthy and between 23 and 43 years of age were recruited for this study. Methods. Surface electromyography (EMG) was used to assess muscle activity from the upper and lower rectus abdominis, external and internal oblique, rectus femoris, latissimus dorsi, and lumbar paraspinal muscles while each exercise was performed. The EMG data were normalized to maximum voluntary muscle contractions. Differences in muscle activity were assessed by a 1-way, repeated-measures analysis of variance. Results. Upper and lower rectus abdominis, internal oblique, and latissimus dorsi muscle EMG activity were highest for the Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees. External oblique muscle EMG activity was highest for the Power Wheel (pike, knee-up, and roll-out) and hanging knee-up with straps. Rectus femoris muscle EMG activity was highest for the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up. Lumbar paraspinal muscle EMG activity was low and similar among exercises. Discussion and Conclusion. The Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees not only were the most effective exercises in activating abdominal musculature but also were the most effective in activating extraneous musculature. The relatively high rectus femoris muscle activity obtained with the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up may be problematic for some people with low back problems.

Sign in / Sign up

Export Citation Format

Share Document