EMG Patterns of the Elbow- and Shoulder-Operating Muscles in Slow Parafrontal Upper Limb Movements under Isotonic Loading

Верещака, И. В.; Gorkovenko, A. V.; Lehedza, O. V.; Abramovych, T. I.; Pilewska, Wiesława; Zasada, Mariusz; Kostyukov, A. I.

doi:10.1007/s11062-019-09779-8

Cited by 6 publications

(3 citation statements)

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“…In the present work, earlier developed methods for the analysis of parafrontal hand movements (Vereshchaka et al, 2018a) have been extended to compare traces with different distances from the subject’s body. This extension allowed for applying multifactor ANOVA to describe quantitatively the EMG activities in the muscles providing these movements.…”

Section: Discussionmentioning

confidence: 99%

“…Quantitative analysis is related to the hysteresis evaluation of the EMGs in the test movements. The following expression, proposed in our preceding study (Vereshchaka et al, 2018a), was used for computation of the normalized areas of the EMG loops:…”

Section: Methodsmentioning

confidence: 99%

“…In both types of movements, the intensities of EMG activity in the shoulder and elbow muscles are correlated with the respective joint torques, consisting of the positive and negative components, each of which corresponds to the predominant activation of the flexor and extensor muscles, respectively. The methods allowing to evaluate the forces acting on the arm muscles and to define character of the muscle contractions (eccentric vs. concentric) along trajectories of the two-joint movements can be found in earlier studies by our group (Kostyukov, 2016; Lehedza et al, 2016; Lehedza, 2017; Gorkovenko, 2018; Kostyukov and Tomiak, 2018; Vereshchaka et al, 2018a). To distinguish various combinations of activity in muscles acting at different joints, we proposed extracting along the movement paths the segments of coinciding and opposing synergies, with active muscles of different joints belonging to the same (flexor and flexor, extensor and extensor) or opposite (flexor and extensor, extensor and flexor) functionalities, respectively (Tomiak et al, 2015, 2016; Kostyukov and Tomiak, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Hysteresis and Synergy of the Central Commands to Muscles Participating in Parafrontal Upper Limb Movements

et al. 2019

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The averaged electromyograms (EMGs) were registered from the arm muscles of ten subjects in movements of the right hand performed under visual guidance on the horizontal plane along linear trajectories going parallel to the frontal plane at various distances from the trunk. The tests consisted of the steady movements (speed 4 cm/s) between two points symmetrical about the shoulder axis; the hand moved firstly from left to right, then in the opposite direction. The tests repeated ten times for each of two equal loads (10.2 N) applied to the hand along movement trajectory in the right- (Fr) or leftward (Fl) directions. The elbow and shoulder flexors reacted predominantly on Fr loads; the extensors were mostly activated by Fl loads. Positional changes of the averaged EMGs in both flexor and extensor muscles belonging to different joints demonstrated hysteresis properties; the respective hysteresis loops had counterclockwise direction in flexors and clockwise in extensors. The muscles predominantly opposing the loading forces of a given direction participate in a cocontraction mode as antagonists when the direction of load is changed; in this case, together with a decrease in the amplitude of the hysteresis loops, their direction is also reversed. The multiplication index of synergy (MIS), which is based on multiplication of the respective normalized averaged EMG records, has been proposed to evaluate quantitatively changes in the synergy effects between various muscle groups. For distal shifts of the movement traces, the synergy effects are shown to be changed in different directions, increasing in flexors and decreasing in extensors. The obtained results demonstrate that the muscle hysteresis leads to strong modification of the central commands during movements.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%