Maximal lactate steady state (MLSS) corresponds to the prolonged constant workload whereby the kinetics of blood lactate concentration clearly increases from steady state. Different results of MLSS in children may reflect specific test protocols or definitions. Three methods corresponding to lactate time courses during 20 min (MLSS I), 16 min (MLSS II), and 8 min (MLSS III) of constant submaximal workload were intraindividually compared in 10 boys. At MLSS I, lactate, V̇O2peak, heart rate, and workload were higher (p < .05) than at MLSS II and at MLSS III. The differences between MLSS I, MLSS II, and MLSS III reflect insufficient contribution to lactate kinetics by testing procedures, strongly depending on the lactate time courses during the initial 10 min of constant workload. Previously published divergent results of MLSS in children seem to reflect a methodological effect more than a metabolic change.
Ralph Beneke, Renate Leithäuser, and Matthias Hütler are with the Department of Sports Medicine at the Free University Berlin, Clayallee 229, 14195 Berlin, Germany. Volker Schwarz is with the Department of Sports Science at Humboldt-University Berlin, Universitätsstraße 3b, 10117 Berlin, Germany. Serge P. von Duvillard is with the Human Performance Laboratory at the University of North Dakota, Department of HPER, Grand Forks, ND 58202-8235.