title: Fixed-point drift and hysteresis in frequency-scaled unimanual coordination.
abstract: Research on human rhythmic coordination has shown that the in-phase and antiphase coordination modes are typically stable and that the coordination of asymmetric effectors frequently exhibits fixed-point drift. The author extended research on symmetry breaking in coordination dynamics by examining a frequency-scaled unimanual pronation-supination task. The results showed symmetry breaking and fixed-point drift, with the radioulnar joint increasingly more phase advanced than the shoulder with increments in movement frequency. Hysteresis was also observed, as the relative phase patterns produced at 3 of the 4 movement frequencies were lower in the upward frequency scaling direction than in the downward direction. These results showed that the dynamic properties of symmetry breaking and fixed-point drift in unimanual pronation-supination movements were consistent with prior research and modeling. The hysteresis effect was explained as potentially being due to the control structures that organize this redundant coordination task.
authors.affiliation: Department of Health and Human Performance, The University of Texas at Brownsville, Brownsville, TX 78520, USA. Eric.James@utb.edu
authors.forename: Eric G
authors.initials: EG
authors.lastname: James
mesh_terms: D000328:Adult; D000465:Algorithms; D003627:Data Interpretation, Statistical; D019277:Entropy; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D009142:Musculoskeletal Physiological Phenomena; D011187:Posture / Q000502:physiology; D011403:Pronation / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D013484:Supination / Q000502:physiology; D055815:Young Adult