scholarly journals Portable acoustic myography - a realistic noninvasive method for assessment of muscle activity and coordination in human subjects in most home and sports settings

2013 ◽  
Vol 1 (2) ◽  
Author(s):  
Adrian P. Harrison ◽  
Bente Danneskiold-Samsøe ◽  
Else M. Bartels
Keyword(s):  
Muscle Activity ◽  
Human Subjects ◽  
Noninvasive Method ◽  
Acoustic Myography

Shin muscle activity and sports surfaces. An electromyographic study

1993 ◽  
Vol 83 (4) ◽  
pp. 181-190 ◽  
Author(s):  
DH Richie ◽  
HA DeVries ◽  
CK Endo
Keyword(s):  
Muscle Damage ◽  
Muscle Activity ◽  
Structural Damage ◽  
Human Subjects ◽  
Floor Surfaces ◽  
The Impact ◽  
Previous Assumption

Twelve human subjects were studied to determine the effect of three different floor surfaces on the medial shin musculature during stationary running. Electromyographic equipment, gated by an accelerometer affixed to the subject's shin, was used to separate the impact (eccentric) phase from the propulsive (concentric) phase of each running step. Excessive eccentric muscle activity has been associated with increased muscle damage, and recent investigations have linked medial tibial shin pain with actual structural damage to the muscle-fascial attachments to the posteromedial aspect of the tibia. Therefore, this study tends to verify the previous assumption that running on hard, noncompliant sport surfaces would predispose running and dancing athletes to shin muscle damage and resultant pain.

scholarly journals Fractionation of muscle activity in rapid responses to startling cues

2017 ◽  
Vol 117 (4) ◽  
pp. 1713-1719 ◽  
Author(s):  
Lauren R. Dean ◽  
Stuart N. Baker
Keyword(s):  
Muscle Activity ◽  
Human Subjects ◽  
Activity Patterns ◽  
Reaction Times ◽  
Principal Component ◽  
Similar Proportion ◽  
Descending Pathways ◽  
Healthy Human ◽  
Wide Range ◽  
The Right

Movements in response to acoustically startling cues have shorter reaction times than those following less intense sounds; this is known as the StartReact effect. The neural underpinnings for StartReact are unclear. One possibility is that startling cues preferentially invoke the reticulospinal tract to convey motor commands to spinal motoneurons. Reticulospinal outputs are highly divergent, controlling large groups of muscles in synergistic patterns. By contrast the dominant pathway in primate voluntary movement is the corticospinal tract, which can access small groups of muscles selectively. We therefore hypothesized that StartReact responses would be less fractionated than standard voluntary reactions. Electromyogram recordings were made from 15 muscles in 10 healthy human subjects as they carried out 32 varied movements with the right forelimb in response to startling and nonstartling auditory cues. Movements were chosen to elicit a wide range of muscle activations. Multidimensional muscle activity patterns were calculated at delays from 0 to 100 ms after the onset of muscle activity and subjected to principal component analysis to assess fractionation. In all cases, a similar proportion of the total variance could be explained by a reduced number of principal components for the startling and the nonstartling cue. Muscle activity patterns for a given task were very similar in response to startling and nonstartling cues. This suggests that movements produced in the StartReact paradigm rely on similar contributions from different descending pathways as those following voluntary responses to nonstartling cues. NEW & NOTEWORTHY We demonstrate that the ability to activate muscles selectively is preserved during the very rapid reactions produced following a startling cue. This suggests that the contributions from different descending pathways are comparable between these rapid reactions and more typical voluntary movements.

Organizing principles for single joint movements: V. Agonist-antagonist interactions

1992 ◽  
Vol 67 (6) ◽  
pp. 1417-1427 ◽  
Author(s):  
G. L. Gottlieb ◽  
M. L. Latash ◽  
D. M. Corcos ◽  
T. J. Liubinskas ◽  
G. C. Agarwal
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Human Subjects ◽  
Single Equation ◽  
Movement Speed ◽  
Joint Movement ◽  
Movement Initiation ◽  
Muscle Activation Patterns ◽  
Movement Distance ◽  
Task Conditions

1. Normal human subjects made discrete elbow flexions in the horizontal plane under different task conditions of initial or final position, inertial loading, or instruction about speed. We measured joint angle, acceleration, and electromyographic signals (EMGs) from two agonist and two antagonist muscles. 2. For many of the experimental tasks, the latency of the antagonist EMG burst was strongly correlated with parameters of the first agonist EMG burst defined by a single equation, expressed in terms of the agonist's hypothetical excitation pulse. Latency is proportional to the ratio of pulse duration to pulse intensity, making it proportional to movement distance and inertial load and inversely proportional to planned movement speed. However, these rules are not sufficient to define the timing of every possible single joint movement. 3. For movements described by the speed-insensitive strategy, the quantity of both antagonist and agonist muscle activity can be uniformly associated with selected kinetic measures that incorporate muscle force-velocity relations. 4. For movements collectively described by the speed-sensitive strategy, (i.e., that have direct or indirect constraints on speed), no single rule can describe all the combinations of agonist-antagonist coordination that are used to perform these diverse tasks. 5. Estimates of joint viscosity were made by calculating the amount of velocity-dependent torque used to terminate movements on target. These estimates are similar to those that have previously been made of limb viscosity during postural maintenance. They imply that a significant component of muscle activity must be used to overcome these forces. 6. These and previous results are all consistent with a dual-strategy hypothesis for those single-joint movements that are sufficiently fast to require pulse-like muscle activation patterns. The major features of such patterns (pulse intensities, durations, and latencies) are determined by central commands programmed in advance of movement initiation. The selection between speed-insensitive or speed-sensitive rules of motoneuron pool excitation is implicitly specified by the nature of speed constraints of the movement task.

scholarly journals Cardiovascular responses to antigravity muscle loading during head-down tilt at rest and after dynamic exercises

2018 ◽  
Author(s):  
Cristiano Alessandro ◽  
Amirehsan Sarabadani Tafreshi ◽  
Robert Riener
Keyword(s):  
Muscle Activity ◽  
Human Subjects ◽  
Cardiovascular Responses ◽  
Bed Rest ◽  
Cardiovascular Regulation ◽  
Upright Position ◽  
The Body ◽  
Healthy Human ◽  
Arterial Blood ◽  
Muscle Loading

AbstractThe physiological processes underlying hemodynamic homeostasis can be modulated by muscle activity and gravitational loading. The effects of antigravity muscle activity on cardiovascular regulation has been observed during orthostatic stress. Here, we evaluated such effects during head-down tilt (HDT). In this posture, the gravitational gradient along the body is different than in upright position, leading to increased central blood volume and reduced venous pooling. We compared the cardiovascular signals obtained with and without antigravity muscle loading during HDT in healthy human subjects, both at rest and during recovery from leg-press exercises. Further, we compared such cardiovascular responses to those obtained during upright position. We found that loading the antigravity muscles during HDT at rest led to significantly higher values of arterial blood pressure than without muscle loading, and restored systolic values to those observed during upright posture. Maintaining muscle loading post-exercise altered the short-term cardiovascular responses, but not the values of the signals five minutes after the exercise. These results demonstrate that antigravity muscle activity modulates cardiovascular regulation during HDT. This modulation should therefore be considered when interpreting cardiovascular responses to conditions that affect both gravity loading and muscle activity, for example bed rest or microgravity.

scholarly journals Muscle Activity During Sleep in Human Subjects, Rats, and Mice: Towards Translational Models of REM Sleep Without Atonia

SLEEP ◽  
2017 ◽  
Vol 40 (4) ◽  
Author(s):  
Alessandro Silvani ◽  
Raffaele Ferri ◽  
Viviana Lo Martire ◽  
Stefano Bastianini ◽  
Chiara Berteotti ◽  
...  
Keyword(s):  
Rem Sleep ◽  
Muscle Activity ◽  
Human Subjects ◽  
Rem Sleep Without Atonia ◽  
Rats And Mice ◽  
Translational Models

Effect of experimental stress on masseter and temporalis muscle activity in human subjects with temporomandibular disorders

1989 ◽  
Vol 34 (6) ◽  
pp. 393-398 ◽  
Author(s):  
J.O. Katz ◽  
J.D. Rugh ◽  
J.P. Hatch ◽  
R.P. Langlais ◽  
G.T. Terezhalmy ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Temporomandibular Disorders ◽  
Human Subjects ◽  
Experimental Stress ◽  
Temporalis Muscle

scholarly journals Cross-species comparison of anticipatory and stimulus-driven neck muscle activity well before saccadic gaze shifts in humans and nonhuman primates

2015 ◽  
Vol 114 (2) ◽  
pp. 902-913 ◽  
Author(s):  
Samanthi C. Goonetilleke ◽  
Leor Katz ◽  
Daniel K. Wood ◽  
Chao Gu ◽  
Alexander C. Huk ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Nonhuman Primates ◽  
Human Subjects ◽  
Neck Muscle ◽  
Visual Responses ◽  
Gaze Shifts ◽  
Head Turning ◽  
Gaze Shift ◽  
Intermediate Layers ◽  
Species Specific

Recent studies have described a phenomenon wherein the onset of a peripheral visual stimulus elicits short-latency (<100 ms) stimulus-locked recruitment (SLR) of neck muscles in nonhuman primates (NHPs), well before any saccadic gaze shift. The SLR is thought to arise from visual responses within the intermediate layers of the superior colliculus (SCi), hence neck muscle recordings may reflect presaccadic activity within the SCi, even in humans. We obtained bilateral intramuscular recordings from splenius capitis (SPL, an ipsilateral head-turning muscle) from 28 human subjects performing leftward or rightward visually guided eye-head gaze shifts. Evidence of an SLR was obtained in 16/55 (29%) of samples; we also observed examples where the SLR was present only unilaterally. We compared these human results with those recorded from a sample of eight NHPs from which recordings of both SPL and deeper suboccipital muscles were available. Using the same criteria, evidence of an SLR was obtained in 8/14 (57%) of SPL recordings, but in 26/29 (90%) of recordings from suboccipital muscles. Thus, both species-specific and muscle-specific factors contribute to the low SLR prevalence in human SPL. Regardless of the presence of the SLR, neck muscle activity in both human SPL and in NHPs became predictive of the reaction time of the ensuing saccade gaze shift ∼70 ms after target appearance; such pregaze recruitment likely reflects developing SCi activity, even if the tectoreticulospinal pathway does not reliably relay visually related activity to SPL in humans.

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.

Development and comprehensive evaluation of a new spring-steel-driven glove for grasping assistance during activities of daily living

2021 ◽  
pp. 095441192110399
Author(s):  
Daniel Chizhik ◽  
Babak Hejrati
Keyword(s):  
Activities Of Daily Living ◽  
Muscle Activity ◽  
Daily Living ◽  
Comprehensive Evaluation ◽  
Human Subjects ◽  
Hand Function ◽  
Spring Steel ◽  
Steel Strips ◽  
Grasping Forces ◽  
Increasing Demand

Millions of people suffer from a decline in grip strength and hand function due to conditions such as chronic disease, injuries, and aging. Hand function decline results in difficulties with performing activities of daily living, where grasping, lifting, and releasing objects are essential. There is an increasing demand for assistive gloves to enhance users’ hand function and improve their independence. This paper presents the design of a new bidirectional lightweight assistive glove and demonstrates its capabilities through comprehensive experiments using human subjects. The developed glove can provide adequate power augmentation for grasping and releasing objects due to its simple yet effective design using spring steel strips and linear actuators. The glove directly transfers assistive forces to users’ fingertips without any complex intermediate mechanism, and its low weight of 196 g promotes its usability. The rigorous experiment design provided a thorough assessment of the developed glove by accounting for both parameters of size and weight of objects and by including subjects with different hand sizes. To quantify the glove’s performance, the subjects’ muscle activity, their finger and thumb joints’ trajectories, and their grasping forces while using the glove were investigated. The glove could generate the necessary grasping forces to assist with lifting common-household objects. The subjects’ muscle activity significantly decreased when using the glove for object manipulation. The trajectories of the index finger and thumb joints when using the glove were dependent on the size of objects similar to natural unassisted grasping. The obtained results demonstrate the glove’s ability for grip power augmentation of individuals with declining hand strength.

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