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Visual field motion during a body pull affects compensatory standing and stepping responses

Citation

St George, RJ and Di Giulio, I and Day, BL, Visual field motion during a body pull affects compensatory standing and stepping responses, Journal of Physiology, 598, (10) pp. 1929-1941. ISSN 0022-3751 (2020) [Refereed Article]


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Copyright Statement

Copyright 2020 The Authors. This is the peer reviewed version of the following article: St George, RJ and Di Giulio, I and Day, BL, Visual field motion during a body pull affects compensatory standing and stepping responses, Journal of Physiology ISSN 0022-3751 (2020). This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article has been published in final form at: http://dx.doi.org/10.1113/JP275436

DOI: doi:10.1113/JP275436

Abstract

The aim of this study was to determine how visual motion evoked by an upper body perturbation during standing affects compensatory postural responses. This was investigated by rotating the visual field forwards or backwards about the ankle, time-locked to a forwards or backwards shoulder pull. Kinematic, kinetic and electromyographic responses were recorded to a range of pull forces over 160 trials in 12 healthy adults (mean = 31 years, S.D. =5.8). Stepping threshold forces and in-place postural responses were compared between conditions.

When the visual field moved in the same direction as the pull, so that the apparent velocity of the body was reduced (SLOW condition), the pull-force required to induce a step was less than when the visual field either rotated in the opposite direction (FAST) or was unaltered (NATURAL). For in-place responses, the body was displaced further in the direction of the pull in the SLOW condition. This was due to a reduction in the resistive force from lower leg muscles 130ms after the visual motion onset. In trials with no pull, the visual motion induced postural responses that were later (290ms) and had smaller amplitudes compared to when visual motion is paired with an unexpected perturbation of the body.

The results suggest that the apparent speed of the visual environment during a perturbation does influence whether a compensatory step is taken, not via a direct effect on the decision to step but by modulating the initial in-place response.

Item Details

Item Type:Refereed Article
Keywords:Vision, balance, perturbation, stepping, optic flow, automatic postural response
Research Division:Health Sciences
Research Group:Sports science and exercise
Research Field:Motor control
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:St George, RJ (Dr Rebecca St George)
ID Code:137865
Year Published:2020
Deposited By:Psychology
Deposited On:2020-03-07
Last Modified:2021-03-18
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