{"title":"Postural Sway and Muscle Activity Dynamics of Upright Standing on Sloped Surfaces.","authors":"Jacey Baldridge, Adam C King","doi":"10.1123/mc.2022-0005","DOIUrl":null,"url":null,"abstract":"<p><p>During upright standing, individuals often use co-contraction muscle activity at the ankle joint when encountering increased postural difficulty; however, this strategy has been shown to be maladaptive. The purpose of the current investigation was to examine the effect of sloped standing on postural sway and muscle co-contraction at the ankle joint as a function of postural difficulty. Twelve young (21.67 ± 1.11 years) adults performed upright standing on flat, declined, and inclined support surfaces. Center of pressure displacements indexed postural sway while electromyography data were collected for the tibialis anterior and gastrocnemius medialis muscles. A co-contraction index and a nonlinear coupling metric (cross-approximate entropy) were computed between ankle dorsiflexor and plantar flexor muscles (tibialis anterior/gastrocnemius medialis) activity. The results showed that higher degrees of postural difficulty led to increased amounts of sway as well as increased sway regularity. Lower co-contraction index was observed for higher degrees of postural difficulty; however, increased dynamic coupling occurred with deviations from the flat standing condition. Overall, increased postural difficulty as manipulated by sloped standing (in either inclined or declined conditions) resulted in individuals adopting a more regular sway trajectory that may be due, in part, to a stronger dynamic coupling strategy occurring at the neuromuscular level.</p>","PeriodicalId":49795,"journal":{"name":"Motor Control","volume":null,"pages":null},"PeriodicalIF":0.9000,"publicationDate":"2022-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Motor Control","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1123/mc.2022-0005","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2022/10/1 0:00:00","PubModel":"Print","JCR":"Q4","JCRName":"NEUROSCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
During upright standing, individuals often use co-contraction muscle activity at the ankle joint when encountering increased postural difficulty; however, this strategy has been shown to be maladaptive. The purpose of the current investigation was to examine the effect of sloped standing on postural sway and muscle co-contraction at the ankle joint as a function of postural difficulty. Twelve young (21.67 ± 1.11 years) adults performed upright standing on flat, declined, and inclined support surfaces. Center of pressure displacements indexed postural sway while electromyography data were collected for the tibialis anterior and gastrocnemius medialis muscles. A co-contraction index and a nonlinear coupling metric (cross-approximate entropy) were computed between ankle dorsiflexor and plantar flexor muscles (tibialis anterior/gastrocnemius medialis) activity. The results showed that higher degrees of postural difficulty led to increased amounts of sway as well as increased sway regularity. Lower co-contraction index was observed for higher degrees of postural difficulty; however, increased dynamic coupling occurred with deviations from the flat standing condition. Overall, increased postural difficulty as manipulated by sloped standing (in either inclined or declined conditions) resulted in individuals adopting a more regular sway trajectory that may be due, in part, to a stronger dynamic coupling strategy occurring at the neuromuscular level.
期刊介绍:
Motor Control (MC), a peer-reviewed journal, provides a multidisciplinary examination of human movement across the lifespan. To keep you abreast of current developments in the field of motor control, it offers timely coverage of important topics, including issues related to motor disorders. This international journal publishes many types of research papers, from clinical experimental to modeling and theoretical studies. These papers come from such varied disciplines as biomechanics, kinesiology, neurophysiology, neuroscience, psychology, physical medicine, and rehabilitation.
Motor Control, the official journal of the International Society of Motor Control, is designed to provide a multidisciplinary forum for the exchange of scientific information on the control of human movement across the lifespan, including issues related to motor disorders.
Motor Control encourages submission of papers from a variety of disciplines including, but not limited to, biomechanics, kinesiology, neurophysiology, neuroscience, psychology, physical medicine, and rehabilitation. This peer-reviewed journal publishes a wide variety of types of research papers including clinical experimental, modeling, and theoretical studies. To be considered for publication, papers should clearly demonstrate a contribution to the understanding of control of movement.
In addition to publishing research papers, Motor Control publishes review articles, quick communications, commentaries, target articles, and book reviews. When warranted, an entire issue may be devoted to a specific topic within the area of motor control.