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dc.contributor.authorKim, D.
dc.contributor.authorHwang, J.-M.
dc.date.accessioned2019-04-05T13:55:10Z
dc.date.available2019-04-05T13:55:10Z
dc.date.issued2018
dc.identifier.urihttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85057469619&doi=10.1371%2fjournal.pone.0207667&partnerID=40&md5=bb7eca95023ffe9ebea6ab093a8f4269
dc.identifier.urihttp://hdl.handle.net/10713/8774
dc.description.abstractThough both contraction of agonist muscles and co-contraction of antagonistic muscle pairs across the ankle joint are essential to postural stability, they are perceived to operate independently of each other, In an antagonistic setup, agonist muscles contract generating moment about the joint, while antagonist muscles contract generating stiffness across the joint. While both work together in maintaining robustness in the face of external perturbations, contractions of agonist muscles and co-contractions of antagonistic muscle pairs across the ankle joint play different roles in responding to and adapting to external perturbations. To determine their respective roles, we exposed participants to repeated perturbations in both large and small magnitudes. The center of pressure (COP) and a cocontraction index (CCI) were used to quantify the activation of agonist muscles and antagonistic muscle pairs across the ankle joint. Our results found that participants generated moment of a large magnitude across the ankle joint - a large deviation in the COP curve - in response to perturbations of a large magnitude (p <0.05), whereas the same participants generated higher stiffness about the ankle - a larger value in CCI - in response to perturbations of a small magnitude (p <0.05). These results indicate that participants use different postural strategies pertaining to circumstances. Further, the moment across the ankle decreased with repetitions of the same perturbation (p <0.05), and CCI tended to remain unchanged even in response to a different perturbation following repetition of the same perturbation (p <0.05). These findings suggest that ankle muscle contraction and co-contraction play different roles in regaining and maintaining postural stability. This study demonstrates that ankle moment and stiffness are not correlated in response to external perturbations. © 2018 Kim, Hwang. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en_US
dc.description.urihttps://dx.doi.org/10.1371/journal.pone.0207667en_US
dc.language.isoEnglishen_US
dc.publisherPublic Library of Scienceen_US
dc.relation.ispartofPLoS ONE
dc.subjectcenter of pressureen_US
dc.subject.meshAnkle Jointen_US
dc.subject.meshPostural Balance--physiologyen_US
dc.titleThe center of pressure and ankle muscle cocontraction in response to anterior-posterior perturbationsen_US
dc.typeArticleen_US
dc.identifier.doi10.1371/journal.pone.0207667
dc.identifier.pmid30496202


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