Rule for scaling shoulder rotation angles while walking through apertures.

BACKGROUND: When an individual is trying to fit into a narrow aperture, the amplitude of shoulder rotations in the yaw dimension is well proportioned to the relative aperture width to body width (referred to as the critical ratio value). Based on this fact, it is generally considered that the centra...

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Main Authors: Takahiro Higuchi, Yasuhiro Seya, Kuniyasu Imanaka
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3483222?pdf=render
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author Takahiro Higuchi
Yasuhiro Seya
Kuniyasu Imanaka
author_facet Takahiro Higuchi
Yasuhiro Seya
Kuniyasu Imanaka
author_sort Takahiro Higuchi
collection DOAJ
description BACKGROUND: When an individual is trying to fit into a narrow aperture, the amplitude of shoulder rotations in the yaw dimension is well proportioned to the relative aperture width to body width (referred to as the critical ratio value). Based on this fact, it is generally considered that the central nervous system (CNS) determines the amplitudes of shoulder rotations in response to the ratio value. The present study was designed to determine whether the CNS follows another rule in which a minimal spatial margin is created at the aperture passage; this rule is beneficial particularly when spatial requirements for passage (i.e., the minimum passable width) become wider than the body with an external object. METHODOLOGY/PRINCIPAL FINDINGS: Eight young participants walked through narrow apertures of three widths (ratio value = 0.9, 1.0, and 1.1) while holding one of three horizontal bars (short, 1.5 and 2.5 times the body width). The results showed that the amplitude of rotation angles became smaller for the respective ratio value as the bar increased in length. This was clearly inconsistent with the general hypothesis that predicted the same rotation angles for the same ratio value. Instead, the results were better explained with a new hypothesis which predicted that a smaller rotation angle was sufficient to produce a constant spatial margin as the bar-length increased in length. CONCLUSION: The results show that, at least under safe circumstances, the CNS is likely to determine the amplitudes of shoulder rotations to ensure the minimal spatial margin being created at one side of the body at the time of crossing. This was new in that the aperture width subtracted from the width of the body (plus object) was taken into account for the visuomotor control of locomotion through apertures.
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spelling doaj.art-5c984279e5d24fdb8e33e895d387838f2022-12-21T17:45:26ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-01710e4812310.1371/journal.pone.0048123Rule for scaling shoulder rotation angles while walking through apertures.Takahiro HiguchiYasuhiro SeyaKuniyasu ImanakaBACKGROUND: When an individual is trying to fit into a narrow aperture, the amplitude of shoulder rotations in the yaw dimension is well proportioned to the relative aperture width to body width (referred to as the critical ratio value). Based on this fact, it is generally considered that the central nervous system (CNS) determines the amplitudes of shoulder rotations in response to the ratio value. The present study was designed to determine whether the CNS follows another rule in which a minimal spatial margin is created at the aperture passage; this rule is beneficial particularly when spatial requirements for passage (i.e., the minimum passable width) become wider than the body with an external object. METHODOLOGY/PRINCIPAL FINDINGS: Eight young participants walked through narrow apertures of three widths (ratio value = 0.9, 1.0, and 1.1) while holding one of three horizontal bars (short, 1.5 and 2.5 times the body width). The results showed that the amplitude of rotation angles became smaller for the respective ratio value as the bar increased in length. This was clearly inconsistent with the general hypothesis that predicted the same rotation angles for the same ratio value. Instead, the results were better explained with a new hypothesis which predicted that a smaller rotation angle was sufficient to produce a constant spatial margin as the bar-length increased in length. CONCLUSION: The results show that, at least under safe circumstances, the CNS is likely to determine the amplitudes of shoulder rotations to ensure the minimal spatial margin being created at one side of the body at the time of crossing. This was new in that the aperture width subtracted from the width of the body (plus object) was taken into account for the visuomotor control of locomotion through apertures.http://europepmc.org/articles/PMC3483222?pdf=render
spellingShingle Takahiro Higuchi
Yasuhiro Seya
Kuniyasu Imanaka
Rule for scaling shoulder rotation angles while walking through apertures.
PLoS ONE
title Rule for scaling shoulder rotation angles while walking through apertures.
title_full Rule for scaling shoulder rotation angles while walking through apertures.
title_fullStr Rule for scaling shoulder rotation angles while walking through apertures.
title_full_unstemmed Rule for scaling shoulder rotation angles while walking through apertures.
title_short Rule for scaling shoulder rotation angles while walking through apertures.
title_sort rule for scaling shoulder rotation angles while walking through apertures
url http://europepmc.org/articles/PMC3483222?pdf=render
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