Correction: The center of pressure and ankle muscle co-contraction in response to anterior-posterior perturbations.
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ABSTRACT:
SUBMITTER: PLOS ONE Staff
PROVIDER: S-EPMC6880986 | biostudies-literature | 2019
REPOSITORIES: biostudies-literature
Publications
Correction: The center of pressure and ankle muscle co-contraction in response to anterior-posterior perturbations.
PloS one 20191127 11
[This corrects the article DOI: 10.1371/journal.pone.0207667.]. ...[more]
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Project description:Though 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 co-contraction 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.
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Project description:An excessive posterior tibial slope has been identified as a potential risk factor for anterior cruciate ligament tears. Anterior closing-wedge osteotomy decreases the posterior slope and can eliminate this risk factor in patients with recurrent instability and greater than 12° posterior slope. We will describe an anterior closing-wedge osteotomy technique performed at the tibial tubercle (TT), in which the TT is not detached to preserve the extensor mechanism attachment. A vertical cut is performed in the sagittal plane just posterior to the TT, leaving a distal cortical hinge. Two proximal parallel K-wires and 2 distal parallel K-wires convergent to the proximal ones are inserted from the anterior cortex on both sides of the tubercle toward the tibial posterior cortex at the posterior cruciate ligament's tibial insertion. Proximal and distal cuts are performed to remove the bone wedge. Reduction is achieved by gentle knee extension. Fixation is completed with 2 staples placed medially and laterally to the TT.
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