Altered movement strategy of chronic ankle instability individuals with postural instability classified based on Nyquist and Bode analyses. (October 2019)

• Record Type: Journal Article
• Authors: Terada, Masafumi; Morgan, Kristin D.; Gribble, Phillip A.
• Is Part Of: Clinical biomechanics. Volume 69(2019)
• Page Start: 39
• Page End: 43
• Publication Date: 2019-10
• Subjects: Sensorimotor control -- Ankle joint injury -- Postural control -- Ankle sprain -- Regularity; Biomechanics -- Periodicals; Osteopathic medicine -- Periodicals; Biomechanics -- Periodicals; Osteopathic Medicine -- Periodicals; 612.76
• DOI: 10.1016/j.clinbiomech.2019.06.020
• Languages: English
• ISSNs: 0268-0033

Abstract

Abstract: Background: The aim of the current study was to assess movement strategies during a single leg balance in chronic ankle instability individuals with unstable postural control strategy identified by Nyquist and Bode analyses in conjunction with sample entropy. Methods: Thirty-three participants with self-reported chronic ankle instability and 22 healthy controls performed single-leg eyes closed static balance trials. The sagittal and frontal plane kinematics in the lower extremity and trunk as well as center of pressure trajectories were recorded during three, 20-second trials. The Nyquist and Bode stability analyses, which classify center of pressure waveforms as stable based on the resulting gain and phase margins, were performed to identify the presence of postural control deficits. Sample entropy was implemented to analyze movement strategies during the task. Findings: Based on the Nyquist and Bode stability analyses, we included 19 out of 33 chronic ankle instability participants with unstable postural control strategy and 16 out of 22 controls with stable postural control strategy in the final analyses. Chronic ankle instability participants demonstrated a significantly lower sample entropy value in sagittal and frontal plane trunk kinematics and sagittal plane hip kinematics compared to the controls. No between-group differences existed in other kinematic measures. Interpretation: The lower sample entropy values in participants with chronic ankle instability indicates that those with postural control deficits may increase reliance on the trunk and hip joint contributions to the maintenance of postural control, reflecting changes in the sensorimotor constraints on movement patterns during the task. Highlights: Ankle and postural instability were associated with decreased kinematic variability. Ankle and postural instability were related to a hip-and-trunk-locked movement. Postural instability is critical prior to determining altered movement strategies. Identifying the disablement exhibited is critical to design rehabilitation programs. Nyquist/Bode criteria are a potential tool for ankle instability homogeneity.