Learning and transfer in motor-respiratory coordination.

Motor-respiratory coordination occurs naturally during exercise, but the number of coordination patterns performed between movement and breathing is limited. We investigated whether participants could acquire novel ratios (either 5:2 or 5:3). To examine complex temporal relationships between movement and breathing, we used lagged return plots that were produced by graphing relative phase against relative phase after a time delay. By the end of practice, participants performed 5:2 consistently and performed 5:3 using more stable ratios (3:2 and 2:1). Lagged return plots revealed that 5:3 learners harnessed the stable inphase and antiphase patterns to stabilize the required ratio. That strategy resulted in the performance of smaller-integer ratios in the production of 5:3 but not 5:2. Despite those differences, there was positive transfer to unpracticed ratios that was similar in both learning conditions. The time series analysis of lagged return plots revealed differences in ratio performance at transfer. Ratios whose component frequencies were farther apart, like 7:2, were performed consistently, while ratios whose component frequencies were more similar, like 5:4, elicited attraction to inphase and antiphase. The implication is that participants can combine more stable chunks of rhythmic behavior to produce more complex ratios.