Cardiorespiratory response to treadmill and bicycle exercise in runners.

Maximal aerobic power and related variables during submaximal work were determined on the bicycle ergometer and on the treadmill in nine long-distance runners and in nine control subjects. During submaximal work, heart rate and pulmonary ventilation were similar with the two exercise procedures in each group, but the runners had lower values than the control subjects. During maximal exercise, oxygen uptake and pulmonary ventilation reached higher levels on the treadmill than on the bicycle egometer. The difference in VO2max was not significant in the control subjects (4.4%), but was more pronounced (12.8%) and highly significantly (p < 0.01) in the runners. The intergroup differences for VO2max between runners and controls were more marked during treadmill running (17.3%) than during bicycle exercise (8.5%). It is concluded tht the differences between the VO2max values obtained on the bicycle ergometer and on the treadmill are influenced by the training conditions of the subjects and that bicycle ergometry leads to a marked underestimation of maximal oxygen uptake in runners.