There is currently no established normative data for cardiopulmonary exercise parameters in the semi-supine position. There is conflicting data regarding the impact of a semi-supine body position on the semi-supine recumbent ergometer on cardiopulmonary exercise parameters. The goal of the current study was to match semi-supine recumbent ergometer tests completed in children/adolescents with those completed on the cycle ergometer and treadmill to identify differences in cardiopulmonary exercise parameters between devices.

Maximal semi-supine recumbent ergometer tests were matched by demographics (age, race/ethnicity, sex, height, weight, and body mass index) to tests completed on the cycle ergometer and treadmill. Groups were compared with two-sample T-tests for numeric variables and Fisher’s exact tests for categorical variables.

There was no difference in demographics between groups. Peak cardiopulmonary exercise parameters (watts, oxygen consumption, heart rate, blood pressure, oxygen saturation, minute ventilation, respiratory exchange ratio, respiratory rate, and anaerobic threshold) were unchanged between semi-supine recumbent ergometer and cycle ergometer, but the ventilatory equivalent of carbon dioxide was higher on the cycle ergometer versus semi-supine recumbent ergometer. Anaerobic threshold, peak oxygen consumption, and peak minute ventilation were lower on the semi-supine recumbent ergometer than on the treadmill.

The uniformity in nearly all cardiopulmonary exercise parameters between the semi-supine recumbent ergometer and cycle ergometer suggests that normative data for the cycle ergometer are a reasonable surrogate for normative data on the semi-supine recumbent ergometer until semi-supine recumbent ergometer-specific normative data are developed.