Higher Accuracy of the Lactate Minimum Test Compared to Established Threshold Concepts to Determine Maximal Lactate Steady State in Running

This study evaluated the accuracy of the lactate minimum test, in comparison to a graded-exercise test and established threshold concepts (OBLA and mDmax) to determine running speed at maximal lactate steady state. Eighteen subjects performed a lactate minimum test, a graded-exercise test (2.4 m·s^-1 start,+0.4 m·s^-1 every 5 min) and 2 or more constant-speed tests of 30 min to determine running speed at maximal lactate steady state. The lactate minimum test consisted of an initial lactate priming segment, followed by a short recovery phase. Afterwards, the initial load of the subsequent incremental segment was individually determined and was increased by 0.1 m·s^-1 every 120 s. Lactate minimum was determined by the lowest measured value (LM_abs) and by a third-order polynomial (LM_pol). The mean difference to maximal lactate steady state was+0.01±0.14 m·s^-1 (LM_abs), 0.04±0.15 m·s^-1 (LM_pol), -0.06±0.31 m·s¹ (OBLA) and -0.08±0.21 m·s¹ (mDmax). The intraclass correlation coefficient (ICC) between running velocity at maximal lactate steady state and LM_abs was highest (ICC=0.964), followed by LM_pol (ICC=0.956), mDmax (ICC=0.916) and OBLA (ICC=0.885). Due to the higher accuracy of the lactate minimum test to determine maximal lactate steady state compared to OBLA and mDmax, we suggest the lactate minimum test as a valid and meaningful concept to estimate running velocity at maximal lactate steady state in a single session for moderately up to well-trained athletes.