Analysis of Thoracoabdominal Motion during Incremental Work Cycle Exercise

We measured thoracoabdominal motion by analyzing changes of rib cage (RC) and abdomen (ABD) motion during cycle ergometry using respiratory inductive plethysmography in eight healthy subjects (8 males). Cycle exercise was performed at three incremental work rates of 60, 90, and 120w for five minutes each and tidal volume (TV) was continuously measured with a respiratory flowmeter on a breath-by-breath basis. It was found that RC motion increased, but ABD motion did not always increase, during incremental work cycle exercise RC motion contributed more to the increase of TV than ABD motion. These results suggest that TV increase was produced more by RC motion than by ABD motion.