Knowledge of Results and Motor Learning

119 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1973.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Postural Stability Margins as a Function of Support Surface Slopes.

This investigation examined the effects of slope of the surface of support (35°, 30°, 20°, 10° Facing(Toe) Down, 0° Flat and 10°, 20°, 25° Facing (Toe) Up) and postural orientation on the margins of postural stability in quiet standing of young adults. The findings showed that the center of pressure-CoP (displacement, area and length) had least motion at the baseline (0° Flat) platform condition that progressively increased as a function of platform angle in both facing up and down directions. The virtual time to collision (VTC) dynamics revealed that the spatio-temporal margins to the functional stability boundary were progressively smaller and the VTC time series also more regular (SampEn-Sample Entropy) as slope angle increased. Surface slope induces a restricted stability region with lower dimension VTC dynamics that is more constrained when postural orientation is facing down the slope. These findings provide further evidence that VTC acts as a control variable in standing posture that is influenced by the emergent dynamics of the individual-environment-task interaction

VTC Anova Graphs

Visual VTC Graph

stats_CoPderivatives

Stats of VT

Data from: Postural stability margins as a function of support surface slopes

This investigation examined the effects of slope of the surface of support (35°, 30°, 20°, 10° Facing(Toe) Down, 0° Flat and 10°, 20°, 25° Facing (Toe) Up) and postural orientation on the margins of postural stability in quiet standing of young adults. The findings showed that the center of pressure—CoP (displacement, area and length) had least motion at the baseline (0° Flat) platform condition that progressively increased as a function of platform angle in both facing up and down directions. The virtual time to collision (VTC) dynamics revealed that the spatio-temporal margins to the functional stability boundary were progressively smaller and the VTC time series also more regular (SampEn–Sample Entropy) as slope angle increased. Surface slope induces a restricted stability region with lower dimension VTC dynamics that is more constrained when postural orientation is facing down the slope. These findings provide further evidence that VTC acts as a control variable in standing posture that is influenced by the emergent dynamics of the individual-environment-task interaction

Group mean (n = 17) for SampEn with between-S standard deviation across all sloped platform conditions.

<p>Group mean (n = 17) for SampEn with between-S standard deviation across all sloped platform conditions.</p

Representative 3D plot of VTC in CoPx and CoPy across all sloped platform conditions.

<p>The heel position is towards CoP<i>y</i> and the toes are oriented towards CoP<i>x</i>.</p

Group mean (n = 17) with between-S standard deviation for polar distribution of VTC mean magnitude and probability of a virtual contact across 20 boundary segments as a function of sloped platform conditions using CoP data.

<p>1^st and 3^rd Row – VTC mean (s), 2^nd and 4^th Row – Probability of VTC.</p