Four commonly utilized metabolic systems fail to produce similar results during submaximal and maximal exercise

Abstract

This study evaluated the reproducibility of four commonly utilized metabolic systems. The metabolic carts and associated electronic cycle ergometers were: (1) the Q‐PLEX I/Corival, (2) SensorMedics 2900/Ergometrics, (3) Medical Graphics Corporation (MGC) 2001/Mijnhardt, and (4) CPX/Medifit. Five individuals (mean age, 32 years; weight, 74 kg; height, 179 cm) experienced in graded exercise testing participated. Duplicate submaximal and maximal protocols were completed on separate days with all four systems. The submaximal power outputs averaged 85, 135, and 190 W and were each 4 minutes in duration. A maximal effort was achieved with a continuous ramp protocol (30 W/min) until exhaustion. All four systems demonstrated excellent reproducibility (usually 5% or less variation) for values reported during either submaximal or maximal exercise. These values were system dependent, however, as evident from a significant difference in submaximal and maximal pulmonary ventilation, oxygen consumption (VO2), carbon di...