Anaerobic threshold, also termed 4.0 mmol.l-1 threshold (AT4), and individual anaerobic threshold (IAT), presumably indicate the workload corresponding to maximal lactate steady state (MLSS) during an incremental workload test. MLSS is the highest blood lactate concentration (BLC) resulting in a steady state during constant workload. The purpose of the present investigation was to ascertain the validity of AT4 and IAT as related to MLSS during rowing ergometry. Nine rowers (mean +/- SD age 20.2 +/- 1.6 yr; HT 187.2 +/- 4.9 cm; WT 81.1 +/- 6.3 kg) performed an incremental load test to determine AT4, IAT and maximal workload and several 30 min constant workloads for MLSS measurement on a mechanical rowing ergometer. The incremental load test was conducted at 215 W and increased by 35 W every 3.0 min. The first 30 min constant workload was conducted at 60% of maximal workload (363.3 +/- 45.1 W). If a constant load test resulted in a steady state of BLC subsequent constant load tests were performed and workload increased by 3% to 10% after each constant load test until no steady state of BLC could be observed. AT4 (287.0 +/- 20.5 W), IAT (287.1 +/- 25.1 W), and BLC at IAT (4.2 +/- 0.8 mmol.l-1) were higher (P < 0.001) compared to MLSS workload (255.1 +/- 17.5 W) and MLSS (3.0 +/- 0.6 mmol.l-1), respectively. Independent of the practical application of AT4 and IAT, in rowing AT4 and IAT do not represent MLSS workload.