RESUMO
This study aimed to investigate the reliability of 1) the key parameters of cycling ergospirometry (maximum power output [Pmax] and oxygen uptake [VÌO2peak], ventilatory thresholds 1 [VT 1] and 2 [VT 2], and cycling efficiency [CE] and gross efficiency [GE]), 2) the commonly used parameters to quantify exhaustion (maximum heart rate [HFmax], respiratory quotient [RQmax], blood lactate concentration [BLAmax], and ratings of perceived exhaustion [RPEmax]), and 3) the kinetics of exercise induced gas exchange measurements (oxygen uptake [VÌO2], carbon dioxide output [VÌCO2], and minute ventilation [VÌE]) using the PowerCube-Ergo metabolic system in consideration of international statistical recommendations. 12 women and 12 men (28â±â4 years; 23.2â±â2.4âkg/m(2)) performed two cycling tests (20 watt/min) separated by one week. The reliability was calculated based on differences in means (t test and effect sizes), retest correlation (intraclass correlation coefficient [ICC]), and within-subject variation (standard error of measurement [SEM]). Of the key parameters of cycling ergospirometry, an excellent reliability (ICC ≥â0.969; pâ=â0.000) and high accuracy (%SEM ≤â4.6) were found for Pmax, VÌO2peak, and VT 1. Of the most commonly used parameters to quantify exhaustion, an excellent reliability (ICCâ=â0.922; pâ=â0.000) and high accuracy (%SEMâ=â1.0) existed only for HFmax. The gas exchange measurements (VÌO2, VÌCO2 und VÌE) of the PowerCube-Ergo were all excellently reliable (ICC ≥â0,991; pâ=â0.000) and the accuracy of VÌO2 (SEMâ=â0.10âl/min) and VÌE (SEMâ=â3.13âl/min) fulfilled the quality guidance of exercise physiology laboratories. For future studies and practical purposes, the results are vital for the decision as to whether a difference between two tests represents a true intervention effect or just a measurement error and for the estimation of required sample sizes.