I know nothing at all about this subject, but I love to do online research. Maybe Gerhard can use some of this info for a translation into English.

Subjects performed two tests on a cycle ergometer: 1) graded exercise test (GXT) and 2) performance exercise test (PXT) to volitional fatigue
Each subject performed a graded exercise stress test (GXT) to volitional fatigue using their own bicycle mounted on a magnetic resistance cycle ergometer. This test determined each subject’s peak aerobic capacity, physiological thresholds and time to exhaustion (TE). During the GXT, the pedal frequency (rev/min) was chosen by the subject as the most comfortable and efficient for each workload. For males, the GXT began at 50 Watts and increased 50 Watts every two minutes until volitional fatigue. Females commenced the GXT at 50 Watts, with increases of 50 Watts every two minutes until the stage beyond 150 Watts. Thereafter, each additional stage increased 30 Watts every two minutes until volitional fatigue. These GXT protocols approximated a 25 Watts/min increase for males and 15 Watts/min increase for females. After reaching exhaustion, the cadence was reduced to a self-selected value and the workload was decreased below 100 Watts to facilitate active recovery. During the test, whole body oxygen consumption (VO2) and carbon dioxide production (VCO2) were quantified using breath-by-breath indirect calorimetry utilizing a ParVo MedicsTM system. Heart rate was measured beat-by-beat utilizing a portable electronic telemetry system (PolarTM), with beat-to-beat data expressed as beats/min for all analyses.
http://72.14.253.104/search?q=cache:5oB-Rvbq2iAJ:www.asep.or...