Muscle synergies in preparation to a step made with and without obstacle

Wang, Yun; Watanabe, Kota; Asaka, Tadayoshi; Wan, Fatao

doi:10.1007/s00421-014-2978-7

Cited by 7 publications

(9 citation statements)

References 31 publications

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“…The muscle groups showed obvious changes when stepping over obstacles (20). Eight pre-amplified wireless transmission modules (DTS Noraxon, Scottsdale, AZ, USA) at a gain of 4,000 were linked with the electrodes to record EMG signals at a sample frequency of 1 kHz.…”

Section: Methodsmentioning

confidence: 99%

Alterations of Muscle Activation Pattern in Stroke Survivors during Obstacle Crossing

Chen

Mao

et al. 2017

Front. Neurol.

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ObjectiveThis study investigates changes in the neuromuscular activation pattern of the lower limb muscles in stroke survivors when crossing obstacles of three different heights.MethodsEight stroke survivors and eight age-, height-, and gender-matched healthy controls were recruited and instructed to cross over obstacles with heights of 10, 20, and 30% leg length. Surface electromyography (EMG) signals were recorded from the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG) of both limbs. Muscle activation signals were normalized to maximum voluntary contraction. Differences between groups and heights were compared using the root mean square of EMG, the cocontraction index of agonist and antagonist muscles, and power spectral analysis based on the mean power frequency (MPF). The correlations between the calculated variables and clinical scales such as Berg Balance Scale and Fugl-Meyer assessment (FMA) were also examined.ResultsDuring the leading limb swing phase, the activation levels of all four muscles were greater in the stroke group than the healthy controls (p < 0.05), and the TA showed increased activation level with increasing obstacle height in both groups (p < 0.05). Cocontraction between the TA and MG was higher in the stroke group during the swing phase of the leading limb and between the RF and BF during the stance phase (p < 0.05). Similarly, for the trailing limb, increased cocontractions between the two pairs of agonist and antagonist muscles were found during the stance phase in the stroke group (p < 0.05). During the crossing stride, the frequency analysis showed significantly smaller MPF values in all four lower limb muscles in the leading limb of stroke survivors compared with healthy controls (p < 0.05). Moreover, significant correlations were found between the FMA scores and the BF and TA activations in the leading limb during the swing phase (p < 0.05).ConclusionGreater activation levels of the lower limb muscles resulted in higher muscular demands for stroke survivors, which might lead to greater difficulty in maintaining balance. The increased cocontraction during obstacle crossing might be compensation for the affected stability and enable safe crossing for stroke survivors. The reduced MPF in the affected limb of the stroke group might be due to impairments in motor units or other complex neuromuscular alterations.

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Section: Methodsmentioning

confidence: 99%

Alterations of Muscle Activation Pattern in Stroke Survivors during Obstacle Crossing

Chen

Mao

et al. 2017

Front. Neurol.

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“…The choice of the obstacle height was based on the following considerations. This task was used in our earlier studies of obstacle crossing [ 5 , 17 , 18 ] and the same high obstacle height on older subjects has been used in previous researches [ 2 , 3 ] to reflect typical high height encountered in everyday life. The obstacle location was chosen in any distance by each subject.…”

Section: Methodsmentioning

confidence: 99%

“…In the ST CS task, the subjects were asked to make a comfortable level step from quiet stance in a self-paced manner. In the ST OS task, the subjects were required to step over an obstacle of 15% body height from quiet stance in a self-paced way [ 5 ]. For each task, the subjects were instructed to look straight ahead and with no restrictions to the arms.…”

Section: Methodsmentioning

confidence: 99%

“…Wang et al investigated the multi-muscle synergies used by healthy young participants to stabilize the anterior-posterior (AP) trajectory of the center of pressure (COP) during preparation to making a step with obstacle [ 5 ]. Within the obstacle-negotiation paradigm, stepping over obstacle task from quiet stance was combined to comfortable level stepping.…”

Section: Introductionmentioning

confidence: 99%

“…While such coordination pattern in the activation of the lower extremities and the trunk muscles are established in the healthy young adults [ 5 - 10 ], to the best of our knowledge there are no studies that evaluate the effect of aging on the multi-M-mode synergies during the stepping over obstacle task. Given that aging is associated with a decline in muscle mass, strength, coordination and postural stability [ 11 , 12 ], comprehending the age-related differences in the muscle synergies during preparation to making a step with obstacle is vital.…”

Section: Introductionmentioning

confidence: 99%

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Muscle synergies in preparation to a step made with obstacle in elderly individuals

Wang

Watanabe

Asaka

2015

Journal of NeuroEngineering and Rehabilitation

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BackgroundTo evaluate if multi-muscle synergies are comprised of flexible combinations of a small number of postural muscles to stabilize the center of pressure (COP) shift during preparation to making a step in the elderly (self-paced level stepping vs. obstacle crossing stepping).MethodsElectromyography (EMG) signals of leg and trunk muscles were recorded. Linear combination of integrated indices of muscle activity (M-modes) and their relationship to changes in the COP shift in the anterior-posterior (AP) direction were first determined. Uncontrolled manifold (UCM) analysis was performed to determine the extent to which variance of the M-modes acted to produce a consistent change in the COP displacement.ResultsThe elderly were capable of stabilizing the COPAP coordinate based on co-varied involvement of the M-modes. The synergy index (∆V) changes in the elderly emerged later (100 ms prior to t0) and its magnitude was smaller as compared to that reported in younger persons.ConclusionsOur study reveals that aging is associated with a preserved ability to explore the flexibility of the M-mode compositions but a decrease ability to use multi-M-mode synergies following a predictable perturbation.

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Muscle synergies underlying control of taking a step during support surface translation

2015

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Muscle synergies in preparation to a step made with and without obstacle

Abstract: These findings demonstrate the robustness of multi-M-mode synergies across different manners of making a step.

Cited by 7 publications

References 31 publications

Alterations of Muscle Activation Pattern in Stroke Survivors during Obstacle Crossing

Alterations of Muscle Activation Pattern in Stroke Survivors during Obstacle Crossing

Muscle synergies in preparation to a step made with obstacle in elderly individuals

Muscle synergies underlying control of taking a step during support surface translation

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