Resumen:
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; V̇O2 max ∼75 ml · kg-1 · 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 · min-1). The following variables were recorded every 100 W until the end of the tests: pulmonary ventilation (V̇E, in / · min-1 BTPS), tidal volume (VT, in IBTPS), breathing frequency (fb, in breaths · min-1), ventilatory equivalents for oxygen (V̇E · V̇O2 -1) and carbon dioxide (V̇E · V̇CO2 -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 /· s-1). The results showed no changes in any of these variables (p...