scholarly journals Investigation of the Intra- and Inter-Limb Muscle Coordination of Hands-and-Knees Crawling in Human Adults by Means of Muscle Synergy Analysis

Entropy ◽  
2017 ◽  
Vol 19 (5) ◽  
pp. 229 ◽  
Author(s):  
Xiang Chen ◽  
Xiaocong Niu ◽  
De Wu ◽  
Yi Yu ◽  
Xu Zhang
Keyword(s):  
Muscle Synergy ◽  
Muscle Coordination ◽  
Limb Muscle ◽  
Human Adults

The effects of differences on sagittal kinematics and muscle coordination during step up and step down in patients with spinal stenosis

2021 ◽  
pp. 1-7
Author(s):  
Sun-Shil Shin ◽  
Won-Gyu Yoo
Keyword(s):  
Spinal Stenosis ◽  
Vastus Lateralis ◽  
Center Of Mass ◽  
Gluteus Medius ◽  
Muscle Coordination ◽  
Limb Muscle ◽  
Compensatory Mechanisms ◽  
Contraction Ratio ◽  
Trunk Posture ◽  
Step Down

BACKGROUND AND OBJECTIVE: Lumbar spinal stenosis (LSS) is a common spinal disorder that causes patients to assume a forward-trunk posture. Spinal alignment affects swing limb angles and stance limb muscle activities. Therefore, we investigated the effects of differences in step up (SU) and step down (SD) tasks on the kinematics of the trunk and swing limb as well as stance limb muscle coordination in patients with LSS. METHODS: Nine elderly female patients diagnosed with LSS were recruited for this study. The sagittal kinematics of the trunk and swing limb and isolated contraction ratio of the gluteus medius (GMed) and vastus lateralis (VL) during SU and SD tasks were measured using a motion analysis system and surface electromyography system. RESULTS: Thoracic (17.71∘± 7.77∘) and spine angles (13.64∘± 11.34∘) as well as swing hip (48.48 ± 12.76) and pelvic angles (7.52 ± 10.33) were significantly greater during SU than SD (10.14 ± 8.41, 10.03 ± 11.03, 29.42 ± 10.57, 3.21 ± 10.11, all P< 0.05, respectively). The isolated contraction ratio of the GMed of the stance limb (34.12% ± 13.28%) was significantly higher during SU than during SD (26.65% ± 10.02%), whereas that of the VL of the stance limb (65.88% ± 13.28%) was significantly lower during SU than during SD (73.35% ± 10.02%, P= 0.011 for both comparisons). CONCLUSIONS: Patients with LSS demonstrated trunk compensatory mechanisms to address swing hip and knee angles. Trunk position affected pelvic limb muscle coordination in the standing support limb. These findings demonstrate that SD are more challenging than SU for patients with LSS, possibly due to reduced ability to generate adequate leg extensor muscular output to safely control the motion of the body’s center of mass. Therefore, trunk positions must be considered when patients with LSS undergo rehabilitation programs, particularly those involving SD or descending stairs, so that healthcare professionals can better assist patients with LSS. In addition, this study provides a background for further studies.

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 Sensorimotor feedback based on task-relevant error robustly predicts temporal recruitment and multidirectional tuning of muscle synergies

2013 ◽  
Vol 109 (1) ◽  
pp. 31-45 ◽  
Author(s):  
Seyed A. Safavynia ◽  
Lena H. Ting
Keyword(s):  
Sagittal Plane ◽  
Balance Control ◽  
Center Of Mass ◽  
The Body ◽  
Muscle Synergy ◽  
Muscle Synergies ◽  
Muscle Coordination ◽  
Initial State ◽  
Sensorimotor Feedback ◽  
Task Level

We hypothesized that motor outputs are hierarchically organized such that descending temporal commands based on desired task-level goals flexibly recruit muscle synergies that specify the spatial patterns of muscle coordination that allow the task to be achieved. According to this hypothesis, it should be possible to predict the patterns of muscle synergy recruitment based on task-level goals. We demonstrated that the temporal recruitment of muscle synergies during standing balance control was robustly predicted across multiple perturbation directions based on delayed sensorimotor feedback of center of mass (CoM) kinematics (displacement, velocity, and acceleration). The modulation of a muscle synergy's recruitment amplitude across perturbation directions was predicted by the projection of CoM kinematic variables along the preferred tuning direction(s), generating cosine tuning functions. Moreover, these findings were robust in biphasic perturbations that initially imposed a perturbation in the sagittal plane and then, before sagittal balance was recovered, perturbed the body in multiple directions. Therefore, biphasic perturbations caused the initial state of the CoM to differ from the desired state, and muscle synergy recruitment was predicted based on the error between the actual and desired upright state of the CoM. These results demonstrate that that temporal motor commands to muscle synergies reflect task-relevant error as opposed to sensory inflow. The proposed hierarchical framework may represent a common principle of motor control across motor tasks and levels of the nervous system, allowing motor intentions to be transformed into motor actions.

Muscle Synergy Analysis Between Young and Elderly People in Standing-Up Motion

2013 ◽  
Vol 25 (6) ◽  
pp. 1038-1049 ◽  
Author(s):  
Qi An ◽  
◽  
Yusuke Ikemoto ◽  
Hajime Asama
Keyword(s):  
Motor Function ◽  
Older Persons ◽  
The Elderly ◽  
Joint Torque ◽  
Daily Activities ◽  
Muscle Synergy ◽  
Elderly Persons ◽  
Muscle Coordination ◽  
Important Data ◽  
Standing Up

Standing up is fundamental to daily activities of the elderly. It is necessary both to enhance muscle strength and to strengthen muscle coordination for improvement of their motor function. In this paper, we extract important data related to muscle coordination, called synergy, to perform standing motion by young and elderly participants. The contribution of muscle synergy to body kinematics is calculated through neural networks that estimate joint torque and body kinematics. To explain deficient motor function in elderly persons, extracted synergy is classified into 4 clusters based on how synergy contribute to body kinematics. Cluster analysis explains that elderly participants have weaker synergy than young persons in bending their backs to generate momentum. Compared to younger persons, older persons require additional muscle coordination to stabilize posture after standing-up in order to avoid falling.

scholarly journals Long-term training modifies the modular structure and organization of walking balance control

2015 ◽  
Vol 114 (6) ◽  
pp. 3359-3373 ◽  
Author(s):  
Andrew Sawers ◽  
Jessica L. Allen ◽  
Lena H. Ting
Keyword(s):  
Neural Control ◽  
Balance Control ◽  
Muscle Synergy ◽  
Muscle Coordination ◽  
Motor Behaviors ◽  
Motor Module ◽  
Biomechanical Constraints ◽  
And Function ◽  
Walking Balance

How does long-term training affect the neural control of movements? Here we tested the hypothesis that long-term training leading to skilled motor performance alters muscle coordination during challenging, as well as nominal everyday motor behaviors. Using motor module (a.k.a., muscle synergy) analyses, we identified differences in muscle coordination patterns between professionally trained ballet dancers (experts) and untrained novices that accompanied differences in walking balance proficiency assessed using a challenging beam-walking test. During beam walking, we found that experts recruited more motor modules than novices, suggesting an increase in motor repertoire size. Motor modules in experts had less muscle coactivity and were more consistent than in novices, reflecting greater efficiency in muscle output. Moreover, the pool of motor modules shared between beam and overground walking was larger in experts compared with novices, suggesting greater generalization of motor module function across multiple behaviors. These differences in motor output between experts and novices could not be explained by differences in kinematics, suggesting that they likely reflect differences in the neural control of movement following years of training rather than biomechanical constraints imposed by the activity or musculoskeletal structure and function. Our results suggest that to learn challenging new behaviors, we may take advantage of existing motor modules used for related behaviors and sculpt them to meet the demands of a new behavior.

scholarly journals Motor module generalization across balance and walking is reduced after stroke

2018 ◽  
Author(s):  
Jessica L. Allen ◽  
Trisha M. Kesar ◽  
Lena H. Ting
Keyword(s):  
Neuromuscular Control ◽  
Muscle Synergy ◽  
Stroke Survivors ◽  
Muscle Coordination ◽  
Overground Walking ◽  
Modular Control ◽  
Motor Module ◽  
Walking Performance ◽  
Walking Speeds ◽  
Reactive Balance

AbstractHere, we examined features of muscle coordination associated with reduced walking performance in chronic stroke survivors. Using motor module (a.k.a. muscle synergy) analysis, we identified differences in the modular control of overground walking and standing reactive balance in stroke survivors compared to age-similar neurotypical controls. In contrast to previous studies that demonstrated reduced motor module number post-stroke, our cohort of stroke survivors did not exhibit a reduction in motor module number compared to controls during either walking or reactive balance. Instead, the pool of motor modules common to walking and reactive balance was smaller, suggesting a reduction in generalizability of motor module function across behaviors. The motor modules common to walking and reactive balance tended to be less variable and more distinct, suggesting more reliable output compared to motor modules specific to one behavior. Indeed, higher levels of motor module generalization was associated with faster walking speeds in stroke survivors. Further, recruitment of a common independent plantarflexor module across both behaviors was associated with faster walking speeds. Our work is the first to show that motor module generalization across walking and balance may help to distinguish important and clinically-relevant differences in walking performance across stroke survivors that would have been overlooked by examining only a single behavior. Finally, as similar relationships between motor module generalization and walking performance have been demonstrated in healthy young adults and individuals with Parkinson’s disease, our work suggests that motor module generalization across walking and balance may be important for well-coordinated walking.New and NoteworthyOur study is the first to simultaneously examine neuromuscular control of walking and standing reactive balance in stroke survivors. We show that motor module generalization across these behaviors (i.e., recruiting common motor modules) is reduced compared to neurotypical controls, which is associated with slower walking speeds. This is true despite no difference in motor module number between groups within each behavior, suggesting that motor module generalization across walking and balance is important for well-coordinated walking.

scholarly journals Effect of acute noxious stimulation to the leg or back on muscle synergies during walking

2015 ◽  
Vol 113 (1) ◽  
pp. 244-254 ◽  
Author(s):  
Wolbert van den Hoorn ◽  
Paul W. Hodges ◽  
Jaap H. van Dieën ◽  
François Hug
Keyword(s):  
Vastus Lateralis ◽  
Plantar Flexion ◽  
Rectus Femoris ◽  
Muscle Synergy ◽  
Noxious Stimulation ◽  
Muscle Synergies ◽  
Muscle Coordination ◽  
Painful Condition ◽  
Leg Muscles ◽  
Pain Location

This study aimed to examine how acute muscle pain affects muscle coordination during gait with consideration of muscle synergies (i.e., group of muscles activated in synchrony), amplitude of muscle activity and kinematics. A secondary aim was to determine whether any adaptation was specific to pain location. Sixteen participants walked on a treadmill during 5 conditions [control, low back pain (LBP), washout LBP, calf pain (CalfP), and washout CalfP]. Five muscle synergies were identified for all of the conditions. Cross-validation analysis showed that muscle synergy vectors extracted for the control condition accounted for >81% of variance accounted for from the other conditions. Muscle synergies were altered very little in some participants ( n = 7 for LBP; n = 10 for CalfP), but were more affected in the others ( n = 9 for LBP; n = 6 for CalfP). No systematic differences between pain locations were observed. Considering all participants, synergies related to propulsion and weight acceptance were largely unaffected by pain, whereas synergies related to other functions (trunk control and leg deceleration) were more affected. Gastrocnemii activity was less during both CalfP and LBP than control. Soleus activity was further reduced during CalfP, and this was associated with reduced plantar flexion. Some lower leg muscles exhibited adaptations depending on pain location (e.g., greater vastus lateralis and rectus femoris activity during CalfP than LBP). Overall, these changes in muscle coordination involve a participant-specific strategy that is important to further explore, as it may explain why some people are more likely to develop persistence of a painful condition.

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