Abstract

The purpose of the study was to investigate the calibration systems of an airbraked ergometer and two mechanically-braked ergometers using a dynamometer and to compare the cardiorespiratory responses to sub-maximal work on each ergometer. The pendulum scale of a mechanically-braked ergometer (Monark), whichassumes negligible friction in the transmission, was found to underestimate the power input between zero and 12 percent at levels ranging from 40 to 245 watts at 50 rpm. Another mechanically-braked ergometer (Cotton) utilizing a weighted belt was also found to underestimate power input. An air-braked ergometer (Repco) conformed closely to its published calibration figures. The latter ergometer is limited in that it utilizes pedal frequencies that vary with power input, however these frequencies are similar to those repoted to beoptimal for highest mechanical efficiency. Using the three calibrated ergometers, no difference was found in net efficiency nor in heart rate response during sub-maximal exercise. However, when the commonly used uncorrected Monark scale was employed, higher steady heart rates (and therefore lower Astrand Nomogram estimations of maximal oxygen consumption) were recorded when compared to those obtained using the Repco machine. Verf.-Referat