Preferred and Induced Coordination Modes during the Acquisition of Bimanual Movements with a 2:1 Frequency Ratio

The generalizability of the preferred in-phase and anti-phase coordination modes under isofrequency conditions to bimanual patterns with a 2:1 frequency ratio was studied. Experiment 1 dealt with spontaneously emerging coordination modes and showed that all participants converged to a similar relative phasing pattern, characterized by an alternation between synchronization of the same and opposite relative peak limb positions. This suggests that movement reversals were exploited as intermittent loci of control during multifrequency tasks. Experiment 2 involved the acquisition of a 2:1 ratio with a 90° phase offset and demonstrated the powerful effect of real-time visual relative motion feedback on performance. Removal of this augmented feedback source resulted in a deterioration of the coordination pattern, accompanied by a regression to the aforementioned spontaneous coordination modes.