Effects of endurance training on the breathing pattern of professional cyclists.

The aim of this longitudinal study was to clarify the changes induced by endurance training on the breathing pattern of 13 professional cyclists (age+/-SD: 24+/-2 years; VO(2 max) approximately 75 ml x kg(-1) x min(-1)) during the three periods (rest, precompetition, and competition) of a sports season. Both the volume and the intensity of training were quantified during these periods. In each session (corresponding to each of the three periods) all subjects performed (1) a pulmonary function test (to measure forced vital capacity [FVC], peak expiratory flow [PEF], and maximal voluntary ventilation [MVV]), and (2) a ramp test until exhaustion on a cycle ergometer (workload increases of 25 W x min(-1)). The following variables were recorded every 100 W until the end of the tests: pulmonary ventilation (VE, in l x min(-1) BTPS), tidal volume (VT, inl BTPS), breathing frequency (f(b), in breaths x min(-1)), ventilatory equivalents for oxygen (VE x VO(2)(-1)) and carbon dioxide (VE x VCO(2)(-1)), inspiratory (TI) and expiratory (TE) times (s), ratio of TI to total respiratory duration or inspiratory "duty cycle" (TI/TTOT, and mean inspiratory flow rate (VT)/TI), in l x s(-1)). The results showed no changes in any of these variables (p>0.05) between the three periods of study, despite significant changes in training loads (i.e., increases in the volume and/or intensity of training throughout the season). These findings suggest that endurance conditioning does not alter the breathing pattern of professional cyclists during an incremental exercise test.