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

Wang, Yun; Watanabe, Kota; Asaka, Tadayoshi

doi:10.1186/s12984-015-0005-9

Cited by 10 publications

(5 citation statements)

References 31 publications

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“…Delayed and reduced ASAs could potentially cause age-related impairments in synergic control [11, 42]. Several studies have shown that impaired control of postural stability happens with healthy aging [12, 13, 43]. In those studies, older adults showed a reduction in the synergy index in whole-body postural tasks in preparation for action.…”

Section: Discussionmentioning

confidence: 99%

“…These values were corrected by integrals of the averaged 10 ms baseline EMG within the ST NS condition in the time interval from − 1000 ms to − 900 ms ( I EMG). ∆ I EMG indices were normalized (∆ I EMG N ) by the maximum magnitude of the integral across experimental conditions [12, 28, 29]. The timing of changes in the muscle activity (EMG onset time, t EMG ) was defined as the instant lasting for at least 25 ms when the average muscle activation across trials for each condition was greater (burst) or smaller (inhibition) than the mean ± 2SD of its baseline activity [15].…”

Section: Methodsmentioning

confidence: 99%

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Effect of dance on multi-muscle synergies in older adults: a cross-sectional study

2019

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BackgroundThe purpose of this study was to investigate the efficacy of dance in the experienced older dancers compared to the inexperienced older adults. We explored the effect of dance on the composition of muscle groups and multi-muscle synergies stabilizing the center of pressure (COP) displacement in preparation to take a step during support surface translation.MethodsEight dance experienced elderly participants were asked to take a step in response to support surface perturbations. Uncontrolled manifold analysis was used to identify muscle modes (M-modes) as factors in the muscle activation space. Variance components in the M-mode space and indices of M-mode synergy stabilizing COP displacement were computed.ResultsThe reciprocal M-modes were observed more frequently in the dance group than in the control group prior to the step initiation. Dance led to higher indices of multi-muscle synergies and earlier anticipatory synergy adjustments during preparation for making a step in response to the support surface translations.ConclusionsDance appeared to be associated with adjustments in both the composition of M-modes and M-mode co-variation patterns resulting in stronger synergies stabilizing COP coordinate in older adults. The results reported here could have clinical relevance when offering a dance approach to balance training for impaired individuals.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effect of dance on multi-muscle synergies in older adults: a cross-sectional study

2019

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“…Wojtara et al proposed a synergy-based stability index during maintaining lateral balance, and this work considers the temporary muscle synergies in postural reflex and automatic response (Wojtara et al, 2014). Wang et al analyzed muscle synergies facing a step made with obstacles in elderly people and revealed a decreased ability to use multiple-mode synergies following a predictable perturbation (Wang et al, 2015). Li et al analyzed muscle synergy in the crus for examining its correlation with plantar/dorsiflexion in the ankle joint (Li et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Muscle Synergy Alteration of Human During Walking With Lower Limb Exoskeleton

Liu

Yin

et al. 2019

Front. Neurosci.

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Muscle synergy reflects inherent coordination patterns of muscle groups as the human body finishes required movements. It may be still unknown whether the original muscle synergy of subjects may alter or not when exoskeletons are put on during their normal walking activities. This paper reports experimental results and presents analysis on muscle synergy from 17 able-bodied subjects with and without lower-limb exoskeletons when they performed normal walking tasks. The electromyography (EMG) signals of the tibialis anterior (TA), soleus (SOL), lateral gastrocnemius (GAS), vastus medialis oblique (VMO), vastus lateralis oblique (VLO), biceps femoris (BICE), semitendinosus (SEMI), and rectus femoris (RECT) muscles were extracted to obtain the muscle synergy. The quantitative results show that, when the subjects wore exoskeletons to walk normally, their mean muscle synergy changed from when they walked without exoskeletons. When the subjects walked with and without exoskeletons, statistically significant differences on sub-patterns of the muscles' synergies between the corresponding two groups could be found.

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“…However, there is conflicting evidence as to how and if at all old age affects motor flexibility during reaching, as motor flexibility during reaching was less (Dutta et al 2013 ; Verrel et al 2012 ), similar (Xu et al 2013 ), or even greater (Krüger et al 2013 ) in old compared with young adults. Moreover, old compared to young adults employ less motor flexibility during multi-finger force coordination (Kapur et al 2010 ; Olafsdottir et al 2007 ; Shinohara et al 2004 ) and standing balance tasks (Hsu et al 2013 , 2014 ), but similar motor flexibility during the initiation of a step over an object (Wang et al 2015 ), walking (Krishnan et al 2013 ) and hand rotation tasks (Skm et al 2012 ) and larger motor flexibility in sit-to-stand tasks (Greve et al 2013 ).…”

Section: Introductionmentioning

confidence: 99%

Old adults preserve motor flexibility during rapid reaching

2017

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PurposeOur ability to flexibly coordinate the available degrees of freedom allows us to perform activities of daily living under various task constraints. Healthy old adults exhibit subclinical peripheral and central nervous system dysfunctions, possibly compromising the flexibility in inter-joint coordination during voluntary movements and the ability to adapt to varying task constraints.MethodWe examined how healthy old (75.4 ± 5.2 years, n = 14) compared with young adults (24.3 ± 2 years, n = 15) make use of the available motor flexibility to adapt to physical and dexterity constraints during a rapid goal-directed reaching task. We manipulated physical and dexterity demands by changing, respectively, external resistance and target size. Motor flexibility was quantified by an uncontrolled manifold (UCM) analysis.ResultsWe found that healthy young and old adults employ similar motor flexibility as quantified by the ratio between goal equivalent and non-goal equivalent variability (V Ratio) and were similarly able to adapt to increases in physical and dexterity demands during goal-directed rapid reaching (V Ratio: p = .092; young: 0.548 ± 0.113; old: 0.264 ± 0.117). Age affected end-effector kinematics. Motor flexibility and end-effector kinematics did not correlate.ConclusionThe data challenge the prevailing view that old age affects movement capabilities in general and provide specific evidence that healthy old adults preserve motor flexibility during a reaching task. Future studies applying UCM analysis should examine if experimental set-ups limit movement exploration, leaving possible age differences undetected.

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

Cited by 10 publications

References 31 publications

Effect of dance on multi-muscle synergies in older adults: a cross-sectional study

Effect of dance on multi-muscle synergies in older adults: a cross-sectional study

Muscle Synergy Alteration of Human During Walking With Lower Limb Exoskeleton

Old adults preserve motor flexibility during rapid reaching

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