The impact of locomotor respiratory coupling on ventilatory and thoraco-abdominal breathing patterns during running

Entrainment is the process in which different rhythms or frequencies spontaneously synchronize. Locomotor Respiratory Coupling (LRC) refers to phase locking of running and breathing so that the same number of steps occur during each breath. Frequency entrainment occurs when the individual can maintain the same ratio between the cadence and the respiratory frequency during the performance. LRC was suggested to improve breathing efficiency, but also to be mechanically insignificant with a negligible contribution to tidal volume. We analyzed the impact of LRC on ventilatory and thoraco-abdominal breathing patterns using opto-electronic plethysmography. Seven healthy males (median age: 24 years) ran for 5 minutes at 10 km/h on a treadmill spontaneously (SB) and with an imposed 2:1 stride-per-breath ratio (CO). In the last 90” of CO running (EX2) minute ventilation was higher than SB. No changes were found in the thoraco-abdominal pattern (figure) and the mean Borg Rating Of Perceived Exertion (SB. 3.8; CO: 3.9). The coefficient of variability of the respiratory rate reduced from 25-30% at SB to 6-7% at CO. CO reduced the variability of the respiratory rate without impacting on the ventilatory and thoraco-abdominal patterns and in the perceived exertion. <fig><object-id>erj;64/suppl_68/PA1590/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>