Displays that facilitate performance of multifrequency ratios during motor-respiratory coordination.

A large number of ratios between movement and breathing are possible, but only a small number have been performed during exercise. The purpose of this study was twofold: (1) to investigate displays that might facilitate the performance of other ratios; and (2) to test predictions from the sine circle map and continued fractions in a model motor-respiratory task in which participants coordinated arm movement and breathing. Displays consisted of either real-time feedback or a template (non-feedback). The accuracy of ratio performance was significantly greater with the template in which the number and relative positioning of movements and breaths was depicted, compared to with real-time feedback. Across displays, the stability of ratio performance conformed to principles of the sine circle map and was significantly greater for ratios with longer continued fractions. Therefore, the motor-respiratory repertoire can be expanded by increasing participants' understanding of the pattern to be performed, but performance is constrained by general dynamical principles. Copyright 2009 Elsevier B.V. All rights reserved.