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Fiona Iredale, Frank Bell and Myra Nimmo

Fourteen sedentary 50- to 55-year-old men were exercised to exhaustion using an incremental treadmill protocol. Mean (±SEM) peak oxygen uptake (V̇O2peak) was 40.5 ± 1.19 ml · kg1 · min−1, and maximum heart rate was 161 ± 4 beats · min−1. Blood lactate concentration was measured regularly to identify the lactate threshold (oxygen consumption at which blood lactate concentration begins to systematically increase). Threshold occurred at 84 ± 2% of V̇O2peak. The absolute lactate value at threshold was 2.9 ± 0.2 mmol · L−1. On a separate occasion, 6 subjects exercised continuously just below their individual lactate thresholds for 25 min without significantly raising their blood lactate levels from the 10th minute to the 25th. The absolute blood lactate level over the last 20 min of the steady-state test averaged 3.7 ± 1.2 mmol · L−1. This value is higher than that elicited at the threshold in the incremental test because of the differing nature of the protocols. It was concluded that although the lactate threshold occurs at a high percentage of V̇O2peak, subjects are still able to sustain exercise at that intensity for 25 min.

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Pitre C. Bourdon, Sarah M. Woolford and Jonathan D. Buckley

Prescribing training loads for endurance athletes often incorporates the measurement of the blood lactate response to incremental exercise in conjunction with heart rate (HR), oxygen consumption ( V ˙ O 2 ), and exercise intensity, and the subsequent calculation of blood lactate thresholds

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Ralph Beneke, Tobias G.J. Weber and Renate M. Leithäuser

It is well known that cycling cadences in terms of pedal revolutions per minute (rpm) affect metabolic responses over a wide range of given exercise intensities. 1 – 4 At low exercise intensities, blood lactate concentration (BLC) and respiratory measures are higher at high than at low rpm. As

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Carlos Augusto Kalva-Filho, Argyris Toubekis, Alessandro Moura Zagatto, Adelino Sanchez Ramos da Silva, João Paulo Loures, Eduardo Zapaterra Campos and Marcelo Papoti

the maximal intensity that can be sustained without substantial increases in blood lactate concentrations ([La − ]), indicating that the anaerobic metabolism is not required and the effort may be sustained for several minutes (eg, >30 min) ( 2 , 8 ). On the other hand, exercises performed above the

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Pedro L. Valenzuela, Javier S. Morales, Carl Foster, Alejandro Lucia and Pedro de la Villa

The lactate threshold (LT), usually defined as the maximum workload that precedes an exponential rise in blood lactate values during an incremental test, is one of the most popular markers of the so-called anaerobic transition. This marker has been extensively used as a predictor of endurance

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Fernando Klitzke Borszcz, Artur Ferreira Tramontin and Vitor Pereira Costa

Maximal lactate steady state (MLSS) is defined as the highest constant intensity of exercise that can be maintained for a longer period without continuous increase in blood lactate concentration ([La − ]), and it is the gold-standard parameter for aerobic evaluation. 1 – 3 MLSS determination is

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Ralph Beneke, Volker Schwarz, Renate Leithäuser, Matthias Hütler and Serge P. von Duvillard

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.

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Fred Brouns, Mikael Fogelholm, Gerrit van Hall, Anton Wagenmakers and Wim H.M. Saris

This study tested the hypothesis that a 3-week oral lactate supplementation affects postexercise blood lactate disappearance in untrained male subjects. Fifteen men were randomly assigned to either a lactate supplementation (n = 8) or a placebo (n = 7) treatment. During the treatment period they drank an oral lactate or a maltodextrin (placebo) supplement twice a day. The lactate drink contained 10 g of lactate as calcium, sodium, and potassium salts. Blood lactate concentrations were studied before, during, and immediately after three exercise tests, both pre-and posttreatment. Peak lactate values for placebo (PL) or lactate (L) treatment groups during different tests were as follows: Test 1 PL, 13.49 ± 3.71; L, 13.70 ± 1.90; Test 2 PL, 12.64 ± 2.32; L, 12.00 ± 2.23; Test 3 PL, 12.29 ± 2.92; L, 11.35 ± 1.38 and were reached 3 min postexercise. The decrease in blood lactate during the long (30- to 45-min) recovery periods amounted to @ 10 mmol/L. Blood lactate changes were highly reproducible. However, a 3-week oral lactate supplementation did not result in differences in lactate disappearance. This study does not support the hypothesis that regular oral lactate intake at rest enhances the removal of lactate during and following exercise, that is, not with the given lactate load and supplementation period.

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Peter Pfitzinger and Patty Freedson

Part 1 reviews the literature concerning peak blood lactate responses to exercise in children. After a brief overview of lactate metabolism, an analysis is presented comparing children to adults regarding peak blood lactate concentration. Possible factors accounting for lower blood lactate concentrations during maximal exercise in children are considered.

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Peter Pfitzinger and Patty Freedson

Part 2 reviews the literature concerning the lactate threshold in children. An analysis is presented comparing children to adults regarding responses to submaximal exercise, and the lactate threshold as a percentage of VO2max. Possible explanations for lower blood lactate concentrations during submaximal exercise in children are considered.