Muscle activation during a reach-to-grasp movement in sitting position: Influence of the distance

2009 ◽  
Vol 19 (2) ◽  
pp. 269-275 ◽  
Author(s):  
A. Bonnefoy ◽  
N. Louis ◽  
P. Gorce
Keyword(s):  
Muscle Activation ◽  
Sitting Position ◽  
Reach To Grasp

scholarly journals Muscle activation patterns in acceleration-based phases during reach-to-grasp movement

2016 ◽  
Vol 28 (11) ◽  
pp. 3105-3111 ◽  
Author(s):  
Keisuke Tokuda ◽  
Bumsuk Lee ◽  
Yasufumi Shiihara ◽  
Kazuhiro Takahashi ◽  
Naoki Wada ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Reach To Grasp ◽  
Activation Patterns ◽  
Muscle Activation Patterns

scholarly journals Phase-dependent deficits during reach-to-grasp after human spinal cord injury

2018 ◽  
Vol 119 (1) ◽  
pp. 251-261 ◽  
Author(s):  
Yuming Lei ◽  
Monica A. Perez
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Muscle Activation ◽  
Cervical Spinal Cord ◽  
Sensory Function ◽  
Movement Duration ◽  
Functional Impairments ◽  
Reach To Grasp ◽  
Cord Injury ◽  
Opening And Closing

Most cervical spinal cord injuries result in asymmetrical functional impairments in hand and arm function. However, the extent to which reach-to-grasp movements are affected in humans with incomplete cervical spinal cord injury (SCI) remains poorly understood. Using kinematics and electromyographic (EMG) recordings in hand and arm muscles we studied the different phases of unilateral self-paced reach-to-grasp movements (arm acceleration, hand opening and closing) to a small cylinder in the more and less affected arms of individuals with cervical SCI and in age-matched controls. We found that SCI subjects showed prolonged movement duration in both arms during arm acceleration, and hand opening and closing compared with controls. Notably, the more affected arm showed an additional increase in movement duration at the time to close the hand compared with the less affected arm. Also, the time at which the index finger and thumb contacted the object and the variability of finger movement trajectory were increased in the more compared with the less affected arm of SCI participants. Participants with prolonged movement duration during hand closing were those with more pronounced deficits in sensory function. The muscle activation ratio between the first dorsal interosseous and abductor pollicis brevis muscles decreased during hand closing in the more compared with the less affected arm of SCI participants. Our results suggest that deficits in movement kinematics during reach-to-grasp movements are more pronounced at the time to close the hand in the more affected arm of SCI participants, likely related to deficits in EMG muscle activation and sensory function. NEW & NOTEWORTHY Humans with cervical spinal cord injury usually present asymmetrical functional impairments in hand and arm function. Here, we demonstrate for the first time that deficits in movement kinematics during reaching and grasping movements are more pronounced at the time to close the hand in the more affected arm of spinal cord injury. We suggest that this is in part related to deficits in muscle activation ratios between hand muscles and a decrease in sensory function.

scholarly journals The comparison of the shoulder muscle activation in patients with rotator cuff tear under an abduction brace among the three postures

2021 ◽  
pp. 14
Author(s):  
Keyword(s):  
Rotator Cuff ◽  
Rotator Cuff Tear ◽  
Supine Position ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Sitting Position ◽  
Cuff Tear ◽  
Upper Trapezius ◽  
Anterior Deltoid

Background: Immobilization using an abduction brace is essential for the relaxation of the rotator cuff and scapular muscles and the prevention of a retear in patients with rotator cuff tear after arthroscopic rotator cuff repair (ARCR). However, thus far, the comparison of the scapular muscle activities has not been compared among different postures under an abduction brace in patients after ARCR. Objectives: The purpose of our study was to compare the scapular muscle activities among the supine position, sitting position, and walking under an abduction brace before and after ARCR Study Design: Observational, repeated measures study. Methods: Twelve patients with full-thickness rotator cuff tears were studied. The mean patient age was 64.7 years. The scapular muscle activations of the ipsilateral limbs were measured using surface electromyography in three postures: supine position, sitting position, and walking. The integrated electromyography relative values of the upper trapezius, anterior deltoid, middle deltoid, and biceps brachii were compared preoperatively and at two weeks after ARCR. Results: The trapezius, biceps brachii, and middle deltoid in the walking showed significantly higher integrated electromyography relative values than those in the supine position, preoperatively and at two weeks after surgery. The anterior deltoid in the sitting position had significantly higher integrated electromyography relative values than those in the supine position. Conclusions: Postures affected the scapular muscle activities in ARCR patients under an abduction brace. Understanding the influence of posture on the scapular muscle activity after ARCR will help rehabilitation accurately and appropriately.

Do Corticomotoneuronal Cells Predict Target Muscle EMG Activity?

2008 ◽  
Vol 99 (3) ◽  
pp. 1169-1986 ◽  
Author(s):  
D. M. Griffin ◽  
H. M. Hudson ◽  
A. Belhaj-Saïf ◽  
B. J. McKiernan ◽  
P. D. Cheney
Keyword(s):  
Firing Rate ◽  
Cortical Neurons ◽  
Muscle Activation ◽  
Cell Activation ◽  
Primary Motor Cortex ◽  
Pearson Correlation ◽  
Cortical Cell ◽  
Emg Activity ◽  
Reach To Grasp ◽  
Muscle Activation Patterns

Data from two rhesus macaques were used to investigate the pattern of cortical cell activation during reach-to-grasp movements in relation to the corresponding activation pattern of the cell's facilitated target muscles. The presence of postspike facilitation (PSpF) in spike-triggered averages (SpTAs) of electromyographic (EMG) activity was used to identify cortical neurons with excitatory synaptic linkages with motoneurons. EMG activity from 22 to 24 muscles of the forelimb was recorded together with the activity of M1 cortical neurons. The extent of covariation was characterized by 1) identifying the task segment containing the cell and target muscle activity peaks, 2) quantifying the timing and overlap between corticomotoneuronal (CM) cell and EMG peaks, and 3) applying Pearson correlation analysis to plots of CM cell firing rate versus EMG activity of the cell's facilitated muscles. At least one firing rate peak, for nearly all (95%) CM cells tested, matched a corresponding peak in the EMG activity of the cell's target muscles. Although some individual CM cells had very strong correlations with target muscles, overall, substantial disparities were common. We also investigated correlations for ensembles of CM cells sharing the same target muscle. The ensemble population activity of even a small number of CM cells influencing the same target muscle produced a relatively good match ( r ≥ 0.8) to target muscle EMG activity. Our results provide evidence in support of the notion that corticomotoneuronal output from primary motor cortex encodes movement in a framework of muscle-based parameters, specifically muscle-activation patterns as reflected in EMG activity.

Planning to reach for a rotating rod

2009 ◽  
Vol 41 (4) ◽  
pp. 207-213 ◽  
Author(s):  
Claes von Hofsten ◽  
Katarina Johansson
Keyword(s):  
Age Groups ◽  
Reach To Grasp ◽  
Almost All

Abstract. Hand adjustments of 6- and 10-month-old infants and adults were studied as they reach to grasp a rotating rod. It was found that the subjects in all three age groups adjusted the hand prospectively to the rotating rod during the approach of it. They also adjusted the reaches to the rotating rod in such a way that almost all of the grasps were overhand ones as predicted by the endpoint comfort hypothesis. Finally, it was found that the rotation of the hand was made up of movement units as translational movements are, and that the approach units were relatively independent of the rotational ones.

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