Cardiac Function and Muscular Oxygen Desaturation in Sprint and Endurance Cohorts during the Incremental Bicycle Ergometry

Abstract

Research background and hypothesis. The objective of this study was to compare the velocity of changes of
cardiac output and muscular oxygen desaturation during the graded exercise stress in endurance and sprint cohorts.
Research  methods.  The  subjects,  13  long  distance  runners  and  11  sprinters,  underwent  a  50W  increase  in
workload every 6 minutes and they exercised till the inability to continue the workout.  The heart rate (HR), cardiac
output and oxygen desaturation (StO 2 ) in lateral head of the rectus femoral muscle were registered.
Research results. The averaged values of change in cardiac output at each stage of workout were similar for
both cohorts. We found statistically significantly higher velocities of changes in StO 2  in the sprint cohort than in
the endurance cohort. The lower physical performance abilities are typical of the sprint cohort compared to the
endurance cohort but three was no difference between the averaged maximal HR values registered at the end of
incremental ergometry. During the exercising with given work rate at stages which became subjectively hard, the
StO 2  decreased to the same smallest level. This means that the same type of change and the same smallest degree of
StO 2  occurs just before the inability to continue the exercising.  
Discussions and conclusions. The endurance cohort features a more extensive slow augmentation and greater
peak values of cardiac output compared to the sprint cohort.  The same type of changes and the same degree of
muscular oxygen desaturation occur at the point of the inability to continue the exercising, but faster changes in
oxygen desaturation in muscular tissue are characteristic of the sprint cohort compared to the sprint cohort.

Keywords:  bicycle ergometry, cardiac output, oxygen desaturation.