title: Transitions of postural coordination as a function of frequency of the moving support platform.
abstract: This study was set-up to investigate the multi-segmental organization of human postural control in a dynamic balance task. The focus was on the coupling between the center of mass (CoM) and center of pressure (CoP) as a candidate collective variable that supports maintaining balance on a sinusoidal oscillating platform in the medial-lateral (ML) plane and was continuously scaled up and then down across a frequency range from 0.2Hz to 1.2Hz. The CoM-CoP coordination changed from in-phase to anti-phase and anti-phase to in-phase at a critical frequency (∼0.4Hz to 0.6Hz, respectively) in the scaling up or down of the support surface frequency, showed hysteresis as a function of the direction of frequency change and critical fluctuations at the transition region. There was evidence of head motion independent of CoM motion at the higher platform frequencies and a learning effect on several of the dynamic indices over 2days of practice. The findings are consistent with the hypothesis of CoM-CoP acting as an emergent collective variable that is supported by the faster time scale motions of the joints and their synergies in postural control.
authors.affiliation: Department of Kinesiology, The Pennsylvania State University, United States. Electronic address: avi.dm16@gmail.com.
authors.forename: Aviroop
authors.initials: A
authors.lastname: Dutt-Mazumder
authors.affiliation: Department of Kinesiology, University of Georgia, United States.
authors.forename: Karl
authors.initials: K
authors.lastname: Newell
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D015992:Body Mass Index; D007839:Functional Laterality; D019416:Head Movements / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011214:Practice, Psychological; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult
keywords: Moving platform; Multi-joint coordination; Phase transition; Postural control