Facilitation of Nonpreferred Coordination Patterns During the Transition from Discrete to Continuous Movements

This study investigates how motor coordination undergoes the passage from a discrete to a continuous movement régime. Participants repeated concatenated discrete movements with each hand such that one hand was lagging the other by a quarter of a cycle (i.e., with a 90 ° phase difference). As movement frequency increased, the tendency to persist in this relative phase competed with a progressive effect of the interlimb coupling favoring 0 ° and 180°. In 61 % of the participants, a switch from a discrete to a continuous motion régime was accompanied by a shift toward the 0 ° or 180°. The 0 ° was more often favored than 180°. The remaining participants sustained a relative phase close to 90 ° even at the highest movement frequency and proved to be more accurate at the initial lowest frequency. These findings indicate that a priming effect may circumvent the tendency to produce preferred patterns and favor the production of nonpreferred patterns and that initial individual differences affect how motor coordination evolves with chang-ing constraints