title: Compensatory mechanisms of balance to the scaling of arm-swing frequency.
abstract: The present study investigated the contribution of the Hof (2007) mechanism 1 (M1-moving the center of pressure (COP) with respect to the vertical projection of the center of mass (COMTotal)); and mechanism 2 (M2-rotating the trunk and upper limbs around the COMTotal) to postural control and the stability of COP-COMTotal cophase as a function of lateral arm-swing frequency. Young adults were instructed to stand still on a force platform while alternating their arm swinging from above the head to the side of their thigh to create perturbations to postural control. Scaling the frequency of arm-swing (random step changes of 0.2 Hz within a bandwidth of 0.2 to 1.6 Hz) increased the SD of COP but decreased the SD of COMTotal. Increments in arm-swing frequency induced a progressive increase in M1 and decrease in M2 in terms of their relative contribution to postural stability. The cophase between COP and COMTotal became more tightly in-phase over increments of arm-swing frequency. These findings show an adaptive compensatory role of M1 and M2 within the stability of COP-COMTotal coupling in the regulation of human balance control.
authors.affiliation: Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, United States. Electronic address: cozy1123@gmail.com.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Ko
authors.affiliation: Center for Autism and Developmental Disabilities, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, United States.
authors.forename: John H
authors.initials: JH
authors.lastname: Challis
authors.affiliation: Department of Kinesiology, The University of Georgia, Athens, GA 30602, United States.
authors.forename: Karl M
authors.initials: KM
authors.lastname: Newell
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology*; D001696:Biomechanical Phenomena; D006257:Head; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011312:Pressure; D060726:Torso; D055815:Young Adult
keywords: Arm-swing; Center of mass; Center of pressure; Postural control