scholarly journals On the Reliability and Repeatability of Surface Electromyography Factorization by Muscle Synergies in Daily Life Activities

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Juri Taborri ◽  
Eduardo Palermo ◽  
Zaccaria Del Prete ◽  
Stefano Rossi
Keyword(s):  
Activity Patterns ◽  
Intraclass Correlation ◽  
Nonnegative Matrix ◽  
Cosine Similarity ◽  
Muscle Synergy ◽  
Coefficient Of Determination ◽  
Muscle Synergies ◽  
Daily Life Activities ◽  
Research Fields ◽  
Emg Signal

Muscle synergy theory is a new appealing approach for different research fields. This study is aimed at evaluating the robustness of EMG reconstruction via muscle synergies and the repeatability of muscle synergy parameters as potential neurophysiological indices. Eight healthy subjects performed walking, stepping, running, and ascending and descending stairs’ trials for five repetitions in three sessions. Twelve muscles of the dominant leg were analyzed. The “nonnegative matrix factorization” and “variability account for” were used to extract muscle synergies and to assess EMG goodness reconstruction, respectively. Intraclass correlation was used to quantify methodology reliability. Cosine similarity and coefficient of determination assessed the repeatability of the muscle synergy vectors and the temporal activity patterns, respectively. A 4-synergy model was selected for EMG signal factorization. Intraclass correlation was excellent for the overall reconstruction, while it ranged from fair to excellent for single muscles. The EMG reconstruction was found repeatable across sessions and subjects. Considering the selection of neurophysiological indices, the number of synergies was not repeatable neither within nor between subjects. Conversely, the cosine similarity and coefficient of determination values allow considering the muscle synergy vectors and the temporal activity patterns as potential neurophysiological indices due to their similarity both within and between subjects. More specifically, some synergies in the 4-synergy model reveal themselves as more repeatable than others, suggesting focusing on them when seeking at the neurophysiological index identification.

scholarly journals Muscle Synergies Reliability in the Power Clean Exercise

2020 ◽  
Vol 5 (4) ◽  
pp. 75
Author(s):  
Paulo D. G. Santos ◽  
João R. Vaz ◽  
Paulo F. Correia ◽  
Maria J. Valamatos ◽  
António P. Veloso ◽  
...  
Keyword(s):  
Nonnegative Matrix Factorization ◽  
Nonnegative Matrix ◽  
Human Movement ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Complex Task ◽  
Muscle Coordination ◽  
High Similarity ◽  
Strength Tests ◽  
Power Clean

Muscle synergy extraction has been utilized to investigate muscle coordination in human movement, namely in sports. The reliability of the method has been proposed, although it has not been assessed previously during a complex sportive task. Therefore, the aim of the study was to evaluate intra- and inter-day reliability of a strength training complex task, the power clean, assessing participants’ variability in the task across sets and days. Twelve unexperienced participants performed four sets of power cleans in two test days after strength tests, and muscle synergies were extracted from electromyography (EMG) data of 16 muscles. Three muscle synergies accounted for almost 90% of variance accounted for (VAF) across sets and days. Intra-day VAF, muscle synergy vectors, synergy activation coefficients and individual EMG profiles showed high similarity values. Inter-day muscle synergy vectors had moderate similarity, while the variables regarding temporal activation were still strongly related. The present findings revealed that the muscle synergies extracted during the power clean remained stable across sets and days in unexperienced participants. Thus, the mathematical procedure for the extraction of muscle synergies through nonnegative matrix factorization (NMF) may be considered a reliable method to study muscle coordination adaptations from muscle strength programs.

scholarly journals Subject-Specific Muscle Synergies in Human Balance Control Are Consistent Across Different Biomechanical Contexts

2010 ◽  
Vol 103 (6) ◽  
pp. 3084-3098 ◽  
Author(s):  
Gelsy Torres-Oviedo ◽  
Lena H. Ting
Keyword(s):  
Muscle Activation ◽  
Balance Control ◽  
Nonnegative Matrix ◽  
The Body ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Support Surface ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Specific Muscle

The musculoskeletal redundancy of the body provides multiple solutions for performing motor tasks. We have proposed that the nervous system solves this unconstrained problem through the recruitment of motor modules or functional muscle synergies that map motor intention to action. Consistent with this hypothesis, we showed that trial-by-trial variations in muscle activation for multidirectional balance control in humans were constrained by a small set of muscle synergies. However, apparent muscle synergy structures could arise from characteristic patterns of sensory input resulting from perturbations or from low-dimensional optimal motor solutions. Here we studied electromyographic (EMG) responses for balance control across a range of biomechanical contexts, which alter not only the sensory inflow generated by postural perturbations, but also the muscle activation patterns used to restore balance. Support-surface translations in 12 directions were delivered to subjects standing in six different postural configurations: one-leg, narrow, wide, very wide, crouched, and normal stance. Muscle synergies were extracted from each condition using nonnegative matrix factorization. In addition, muscle synergies from the normal stance condition were used to reconstruct muscle activation patterns across all stance conditions. A consistent set of muscle synergies were recruited by each subject across conditions. When balance demands were extremely different from the normal stance (e.g., one-legged or crouched stance), task-specific muscle synergies were recruited in addition to the preexisting ones, rather generating de novo muscle synergies. Taken together, our results suggest that muscle synergies represent consistent motor modules that map intention to action, regardless of the biomechanical context of the task.

scholarly journals Modular Organization of Muscle Synergies to Achieve Movement Behaviors

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Kunkun Zhao ◽  
Zhisheng Zhang ◽  
Haiying Wen ◽  
Zihan Wang ◽  
Jiankang Wu
Keyword(s):  
Motion Control ◽  
Control Mechanism ◽  
Nonnegative Matrix ◽  
Movement Patterns ◽  
Motor Dysfunction ◽  
Muscle Synergy ◽  
Modular Organization ◽  
Muscle Synergies ◽  
Motion Primitives ◽  
Motion Control Mechanism

Muscle synergy has been applied to comprehend how the central nervous system (CNS) controls movements for decades. However, it is not clear about the motion control mechanism and the relationship between motions and muscle synergies. In this paper, we designed two experiments to corroborate the hypothesis: (1) motions can be decomposed to motion primitives, which are driven by muscle synergy primitives and (2) variations of motion primitives in direction and scale are modulated by activation coefficients rather than muscle synergy primitives. Surface electromyographic (EMG) signals were recorded from nine muscles of the upper limb. Nonnegative matrix factorization (NMF) was applied to extract muscle synergy vectors and corresponding activation coefficients. We found that synergy structures of different movement patterns were similar (α=0.05). The motion modulation indexes (MMI) among movement patterns in reaching movements showed apparent differences. Merging coefficients and reconstructed similarity of synergies between simple motions and complex motions were significant. This study revealed the motion control mechanism of the CNS and provided a rehabilitation and evaluation method for patients with motor dysfunction in exercise and neuroscience.

Muscle Synergies Based on a Biomechanical Biaxial Isometric Shoulder Model Minimizing Fatigue

2010 ◽  
Author(s):  
Mohamadreza Nassajian Moghadam ◽  
Kamiar Aminian ◽  
Mohsen Asghari ◽  
Mohammad Parnianpour
Keyword(s):  
Shoulder Joint ◽  
Degrees Of Freedom ◽  
Muscle Activation ◽  
Glenohumeral Joint ◽  
Nonnegative Matrix ◽  
Factorization Method ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Specific Direction ◽  
Activation Data

In this study we utilize the concept of synergy formation as a simplifying control strategy to manage the high number of degrees of freedom presented in the maintenance of the posture of the shoulder joint. We address how to find the muscle synergy recruitment map to the biomechanical demands (biaxial external torque) during an isometric shoulder task. We use a numerical optimization based shoulder model to obtain muscle activation levels when a biaxial external isometric torque is exposed at the shoulder glenohumeral joint. In the numerical simulations, different shoulder torque vectors parallel to the horizontal plane are considered. For each selected direction for the torque, the resulting muscle activation data are calculated and then used for grouping muscles in some fixed element synergies by nonnegative matrix factorization method Next, the muscle synergies are converted from activation level to the torque space to see how muscle synergy recruitment addresses the torque production in a specific direction at the shoulder joint. The results confirmed our expectation that the few dominant synergies are sufficient to address the torque vectors in directions which coincide to the basic vectors of torque space, such that each muscle contributed to more than one synergy.

Shared muscle synergies in human walking and cycling

2014 ◽  
Vol 112 (8) ◽  
pp. 1984-1998 ◽  
Author(s):  
Filipe O. Barroso ◽  
Diego Torricelli ◽  
Juan C. Moreno ◽  
Julian Taylor ◽  
Julio Gomez-Soriano ◽  
...  
Keyword(s):  
Nonnegative Matrix ◽  
Muscular Activity ◽  
Muscle Synergy ◽  
Emg Activity ◽  
Modular Organization ◽  
Muscle Synergies ◽  
Supporting Evidence ◽  
Healthy Humans ◽  
Common Control ◽  
Secondary Objective

The motor system may rely on a modular organization (muscle synergies activated in time) to execute different tasks. We investigated the common control features of walking and cycling in healthy humans from the perspective of muscle synergies. Three hypotheses were tested: 1) muscle synergies extracted from walking trials are similar to those extracted during cycling; 2) muscle synergies extracted from one of these motor tasks can be used to mathematically reconstruct the electromyographic (EMG) patterns of the other task; 3) muscle synergies of cycling can result from merging synergies of walking. A secondary objective was to identify the speed (and cadence) at which higher similarities emerged. EMG activity from eight muscles of the dominant leg was recorded in eight healthy subjects during walking and cycling at four matched cadences. A factorization technique [nonnegative matrix factorization (NNMF)] was applied to extract individual muscle synergy vectors and the respective activation coefficients behind the global muscular activity of each condition. Results corroborated hypotheses 2 and 3, showing that 1) four synergies from walking and cycling can successfully explain most of the EMG variability of cycling and walking, respectively, and 2) two of four synergies from walking appear to merge together to reconstruct one individual synergy of cycling, with best reconstruction values found for higher speeds. Direct comparison of the muscle synergy vectors of walking and the muscle synergy vectors of cycling ( hypothesis 1) produced moderated values of similarity. This study provides supporting evidence for the hypothesis that cycling and walking share common neuromuscular mechanisms.

Is interindividual variability of EMG patterns in trained cyclists related to different muscle synergies?

2010 ◽  
Vol 108 (6) ◽  
pp. 1727-1736 ◽  
Author(s):  
François Hug ◽  
Nicolas A. Turpin ◽  
Arnaud Guével ◽  
Sylvain Dorel
Keyword(s):  
Interindividual Variability ◽  
Nonnegative Matrix ◽  
Rectus Femoris ◽  
Biceps Femoris ◽  
Surface Emg ◽  
Constant Load ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Lower Limb Muscles ◽  
Emg Patterns

Our aim was to determine whether muscle synergies are similar across trained cyclists (and thus whether the same locomotor strategies for pedaling are used), despite interindividual variability of individual EMG patterns. Nine trained cyclists were tested during a constant-load pedaling exercise performed at 80% of maximal power. Surface EMG signals were measured in 10 lower limb muscles. A decomposition algorithm (nonnegative matrix factorization) was applied to a set of 40 consecutive pedaling cycles to differentiate muscle synergies. We selected the least number of synergies that provided 90% of the variance accounted for VAF. Using this criterion, three synergies were identified for all of the subjects, accounting for 93.5 ± 2.0% of total VAF, with VAF for individual muscles ranging from 89.9 ± 8.2% to 96.6 ± 1.3%. Each of these synergies was quite similar across all subjects, with a high mean correlation coefficient for synergy activation coefficients (0.927 ± 0.070, 0.930 ± 0.052, and 0.877 ± 0.110 for synergies 1– 3, respectively) and muscle synergy vectors (0.873 ± 0.120, 0.948 ± 0.274, and 0.885 ± 0.129 for synergies 1– 3, respectively). Despite a large consistency across subjects in the weighting of several monoarticular muscles into muscle synergy vectors, we found larger interindividual variability for another monoarticular muscle (soleus) and for biarticular muscles (rectus femoris, gastrocnemius lateralis, biceps femoris, and semimembranosus). This study demonstrated that pedaling is accomplished by the combination of the similar three muscle synergies among trained cyclists. The interindividual variability of EMG patterns observed during pedaling does not represent differences in the locomotor strategy for pedaling.

scholarly journals Human Muscle Synergy Analysis to Approach the Understanding of Brain Control Algorithm

2021 ◽  
Author(s):  
Fereidoun Nowshiravan Rahatabad ◽  
Parisa Rangraz
Keyword(s):  
Control Algorithm ◽  
Functional Unit ◽  
Recurrence Plot ◽  
Human Muscle ◽  
Muscle Synergy ◽  
Hand Movements ◽  
Muscle Synergies ◽  
Emg Signal ◽  
Random Motions ◽  
Non Negative Matrix Factorization

Purpose: Muscle synergy is a functional unit that coordinates the activity of a number of muscles. In this study, the extraction of muscle synergies in three types of hand movements in the horizontal plane is investigated. Materials and Methods: So, after constructing the tracking pattern of three signals, by LabVIEW, the Electromyography (EMG) signal from six muscles of hand was recorded. Then time-constant muscle synergies and their activity curves from the recorded EMG signals were extracted using Non-negative Matrix Factorization (NMF) method. Results: Comparison of these patterns showed that the non-random motions’ synergies were more similar than the random motions among different individuals. It was observed that in all movements, the similarity of the synergies in one cluster was greater than the similarity of their corresponding activation curves. Conclusion: The results showed that the complexity of the recurrence plot in random movement is greater than that of the other movements.

scholarly journals Identifying Representative Synergy Matrices for Describing Muscular Activation Patterns During Multidirectional Reaching in the Horizontal Plane

2010 ◽  
Vol 103 (3) ◽  
pp. 1532-1542 ◽  
Author(s):  
Silvia Muceli ◽  
Andreas Trøllund Boye ◽  
Andrea d'Avella ◽  
Dario Farina
Keyword(s):  
Linear Combination ◽  
Upper Limb ◽  
Horizontal Plane ◽  
Degrees Of Freedom ◽  
Nonnegative Matrix ◽  
Coefficient Of Determination ◽  
Muscle Synergies ◽  
Large Set ◽  
Reaching Task ◽  
Multijoint Movements

Muscle synergies have been proposed as a simplifying principle of generation of movements based on a low-dimensional control by the CNS. This principle may be useful for movement restoration by, e.g., functional electrical stimulation (FES), if a limited set of synergies can describe several functional tasks. This study investigates the possibility of describing a multijoint reaching task of the upper limb by a linear combination of one set of muscle synergies common to multiple directions. Surface electromyographic (EMG) signals were recorded from 12 muscles of the dominant upper limb of eight healthy men during single-joint movements and a multijoint reaching task in 12 directions in the horizontal plane. The movement kinematics was recorded by a motion analysis system. Muscle synergies were extracted with nonnegative matrix factorization of the EMG envelopes. Synergies were computed either from the single-joint movements to describe the two degrees of freedom independently or from the multijoint movements. On average, the multijoint reaching task could be accurately described in all the directions (coefficient of determination >0.85) by a linear combination of either four synergies extracted from the individual degrees of freedom or three synergies extracted from multijoint movements in at least three reaching directions. These results indicate that a large set of multijoint movements can be generated by a synergy matrix of limited dimensionality and common to all directions if the synergies are extracted from a representative number of directions. The linear combination of synergies may thus be used in strategies for restoring functions, such as FES.

scholarly journals Feasibility of Muscle Synergy Outcomes in Clinics, Robotics, and Sports: A Systematic Review

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Juri Taborri ◽  
Valentina Agostini ◽  
Panagiotis K. Artemiadis ◽  
Marco Ghislieri ◽  
Daniel A. Jacobs ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Motor Task ◽  
Muscle Synergy ◽  
Modular Organization ◽  
Single Subject ◽  
Muscle Synergies ◽  
Neural Encoding ◽  
Research Fields ◽  
The Central Nervous System

In the last years, several studies have been focused on understanding how the central nervous system controls muscles to perform a specific motor task. Although it still remains an open question, muscle synergies have come to be an appealing theory to explain the modular organization of the central nervous system. Even though the neural encoding of muscle synergies remains controversial, a large number of papers demonstrated that muscle synergies are robust across different tested conditions, which are within a day, between days, within a single subject, and between subjects that have similar demographic characteristics. Thus, muscle synergy theory has been largely used in several research fields, such as clinics, robotics, and sports. The present systematical review aims at providing an overview on the applications of muscle synergy theory in clinics, robotics, and sports; in particular, the review is focused on the papers that provide tangible information for (i) diagnosis or pathology assessment in clinics, (ii) robot-control design in robotics, and (iii) athletes’ performance assessment or training guidelines in sports.

Development and validation of a questionnaire measuring knowledge, attitudes, and practices (KAP) to healthy eating and activity patterns in school children (HEAPS)

2021 ◽  
pp. 026010602098235 ◽  
Author(s):  
Panchali Moitra ◽  
Preeti Verma ◽  
Jagmeet Madan
Keyword(s):  
Correlation Coefficient ◽  
Healthy Eating ◽  
School Children ◽  
Content Validity ◽  
Activity Patterns ◽  
Intraclass Correlation ◽  
Validity And Reliability ◽  
Attitudes And Practices ◽  
Item Content ◽  
Knowledge Attitudes And Practices

Background: Development of culturally appropriate and psychometrically sound instruments that measure knowledge and health behaviors of children will help to inform appropriate interventions. Aim: To develop and test the validity and reliability of a questionnaire measuring knowledge, attitudes, and practices to healthy eating and activity patterns in school children in India. Methods: Review of literature, focus-group discussions, and theoretical constructs of the Health Belief Model guided the development of an item pool. Face and content validity were assessed by children and a panel of experts and the item content validity, item difficulty, and discrimination indices were calculated. Construct validity was determined using the principal axis method of exploratory factor analysis among a cross-sectional sample of children ( n=252). Internal consistency (Cronbach α values >0.7) and test-retest reliability (intraclass correlation coefficient values >0.75) were estimated. Results: Item content validity index for clarity and relevance were satisfactory (>0.80) and internal consistency for knowledge (Kuder-Richardson 20 = 0.832), attitude (Cronbach’s α = 0.912), and practice items (Cronbach’s α = 0.769) were good. Four factors (children’s eating habits, family dietary practices, and consumption of healthy and unhealthy foods) and two factors (moderate to vigorous activities and sedentary activities) explained 67.7% and 48.2% of the total variance in practice items. Intraclass correlation coefficient estimates ranged from good to excellent (0.72–0.99). Conclusions: The results of the validity and reliability of the 84-item knowledge, attitudes, and practices to healthy eating and activity patterns in schoolchildren questionnaire were promising. The detailed description of the methodology employed may prove useful to researchers conducting similar studies in children.

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