Organization of Compensatory Postural Coordination Patterns

• Published in: Journal of motor behavior 2003-12, Vol.35 (4), p.325-342
• Main Authors: Ko, Young-Gyu, Challis, John H., Stitt, Joseph P., Newell, Karl M.
• Format: Article
• Language: English
• Subjects: Adult; Anatomy; Biological and medical sciences; Biomechanical Phenomena; Body Mass Index; compensatory postural coordination; Coordination; degrees of freedom; Exhibits; Fourier Analysis; Freedom; Fundamental and applied biological sciences. Psychology; Gravitation; Humans; Joints - physiology; Kinesthesis - physiology; Male; Mathematical Computing; Orientation - physiology; Postural Balance - physiology; Reference Values; self-organization; Signal Processing, Computer-Assisted; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 0022-2895; 1940-1027
• DOI: 10.1080/00222890309603154

The authors investigated whether compensatory postural coordination patterns are organized according to the same dynamical principles as are nonequilibrium phase transitions. Eight participants were asked to maintain upright balance on a moving platform that was sinusoidally translated in the anterior-posterior direction and was systematically increased and decreased 0.19 Hz as a step function every 10 platform cycles through the frequency range 0.19-1.46 Hz. At low platform frequencies, all participants exhibited small joint angular motions with high variability, and the relative phase between the joint motions exhibited drifting patterns and large fluctuations. As platform frequency increased, the amplitude of joint motion increased systematically and joint-specific oscillatory patterns emerged. The findings provided no evidence for a Hopf bifurcation or hysteresis in the transitions of postural coordination modes, however, or, mote generally, a basis for distinguishing the relevance of linear versus nonlinear models of postural control.