Author ORCID Identifier
Stergiou - https://orcid.org/0000-0002-9737-9939
Document Type
Article
Publication Date
2-3-2020
Abstract
Background
Voluntary shifting body weight in the anteroposterior direction is an important element of daily life activities, such as rising from a chair or initiating a step. In order to accommodate the daily-life challenges of such tasks, voluntary postural sway needs to be flexible and variable.
Research question
In this study we asked how whole-body tracking of a complex visual target motion with the concurrent provision of feedback modulates the variability of voluntary sway.
Methods
Twenty young adults (age: 27.10 ± 9.15years, height: 170.73 ± 9.40 cm, mass: 62.84 ± 11.48 kg) performed 132 cycles of voluntary antero-posterior sway, on a force platform, under two conditions: a) self-paced sway and b) swaying while tracking the complex motion of a visual target. Magnitude and temporal structure of variability of postural sway were investigated with the Coefficient of Variance (CoV) and the fractal exponent α, respectively. This analysis was performed for sway cycle duration, amplitude and velocity. The cross-correlation function between the target and sway cycle parameters was computed as a measure of visuo-postural coupling.
Results
The CoV of sway cycle amplitude, duration and velocity increased during active tracking of the complex target. Fractal exponent α increased for sway cycle amplitude but decreased for cycle duration and remained unchanged for sway velocity. The cross-correlation function revealed a consistent peak at lag+1 indicating an asynchrony between the target and sway cycle duration, while the peak cross-correlation for cycle amplitude was noted at lag 0.
Significance
Swaying to the complex motion of a visual target improves the variability of sway cycle amplitude, at the cost of cycle duration. This is associated with a more synchronous spatial than temporal coupling to the visual target motion. This knowledge could inform the design of postural tracking paradigms as appropriate exercise interventions, for improving voluntary sway in populations with reduced limits of stability (i.e. older adults).
Journal Title
Gait & Posture
Volume
77
First Page
125
Last Page
131
Recommended Citation
Sotirakis, H., Patikas, D., Stergiou, N., & Hatzitaki, V. (2020, February 3). Sway to the complex motion of a visual target affects postural sway variability. Gait & Posture, 77, 125-131. https://doi.org/10.1016/j.gaitpost.2020.01.026
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Comments
This is an Accepted Manuscript of an article published by Elsevier in Gait & Posture on February 3, 2020, available online: https://doi.org/10.1016/j.gaitpost.2020.01.026