Pulmonary function during cycling and running in triathletes

摘要

Aim. Running performance has become key to the triathlete's overall performance. We still know relatively little about the factors that define the ability to perform a good run after cycling, however, and the perception of discomfort during the first minutes of this post-cycling running has yet to be satisfactorily explained. Pulmonary volumes (i.e., residual volume, RV, and functional residual capacity, FRC) have been demonstrated to be impaired after a cycle-run succession in triathletes but not after a run-run succession that is matched in terms of intensity and duration. Cycling in itself and/or the succession of two different exercises (i.e., cycling and running) may explain this phenomenon, but the exact mechanism has not yet been determined. Methods. Thirteen young male triathletes participated in three different exercise trials: 30 min of cycling followed by 20 min of running (C-R), 30 min of control cycling (C) and 20 min of control running (R). Pulmonary volumes and flows were measured 10 min before and 10 min after each trial. During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. Results. The results showed that 1) C induced significant increases in RV, FRC and RV/TLC (2.31 +- 0.18 vs 2.01 +- 0.17 L, 4.35 +- 0.24 vs 4.01 +- 0.25 L, and 27.21 +- 1.62 vs 23.98 +- 1.55, respectively, after versus before C) and 2) there were no significant pulmonary volume or flow changes after C-R or R. Conclusion. We concluded that 1) cycling exercise in itself seems to increase the post-exercise pulmonary volume changes which could lead to respiratory muscle alterations and 2) one likely explanation for this finding appears to be the crouched position of cycling.