Manipulating graded exercise test variables affects the validity of the lactate threshold and V˙O2peak
To determine the validity of the lactate threshold (LT) and maximal oxygen uptake ( _ VO 2max ) determined during graded exercise test (GXT) of different durations and using different LT calculations. Trained male cyclists (n = 17) completed five GXTs of varying stage length (1, 3, 4, 7 and 10 min) to establish the LT, and a series of 30-min constant power bouts to establish the maximal lactate steady state (MLSS). _ VO 2 was assessed during each GXT and a subsequent verification exhaustive bout (VEB), and 14 different LTs were calculated from four of the GXTs (3, 4, 7 and 10 min)-yielding a total 56 LTs. Agreement was assessed between the highest _ VO 2 measured during each GXT ( _ VO 2peak ) as well as between each LT and MLSS. _ VO 2peak and LT data were analysed using mean difference (MD) and intraclass correlation (ICC).