title: Postural responses during the various frequencies of anteroposterior perturbation.
abstract: This study investigated the characteristics of dynamic postural responses when subjects attempted to maintain an upright standing position on a support plate during continuous sinusoidal perturbation in the anterior-posterior direction. Fifteen healthy young subjects participated in the experiment. Body movement patterns during the perturbation were captured and analyzed using a 3D motion analysis system (APAS 3D motion analysis, Ariel Dynamics Inc.). Seven markers were attached on the subject's body to measure and analyze the motion patterns. The markers were positioned at the head, chest, hip, right knee, left knee, right ankle, and left ankle. Five different frequencies of motion were applied to the support surface: 0.1, 0.5, 1.0, 1.5, and 2.0 Hz with a 4-cm path of motion at the base. The experiments measured dynamic postural responses in a condition were subjects had their eyes open. The results showed that the median frequency of the knee and ankle increased in all frequency bands. Following an increase in the frequency of the perturbation, the postural control strategy was changed from the ankle strategy to a combined strategy. These experimental results could be applied to the dynamic postural training for the elderly and to rehabilitation training for patients to improve their ability for postural control.
authors.affiliation: Division of Biomedical Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeonbuk 561-756, Republic of Korea.
authors.forename: Kap Soo
authors.initials: KS
authors.lastname: Han
authors.affiliation: Division of Biomedical Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeonbuk 561-756, Republic of Korea.
authors.forename: Sun Hye
authors.initials: SH
authors.lastname: Shin
authors.affiliation: Division of Biomedical Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeonbuk 561-756, Republic of Korea.
authors.forename: Chang Ho
authors.initials: CH
authors.lastname: Yu
authors.affiliation: Division of Biomedical Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeonbuk 561-756, Republic of Korea.
authors.forename: Tae Kyu
authors.initials: TK
authors.lastname: Kwon
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D010812:Physical Stimulation / Q000379:methods; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*
keywords: Postural control; dynamic postural balance; horizontal translation; motion base