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
Fernando Klitzke Borszcz, Artur Ferreira Tramontin and Vitor Pereira Costa
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.
Erin Calaine Inglis, Danilo Iannetta, Louis Passfield and Juan M. Murias
, the boundary separating tolerable and nontolerable exercise) and is often identified by measures including the maximal lactate steady state (MLSS) or critical power (CP). 3 Although the accuracy for determining this intensity is best obtained in a laboratory setting, this is not always feasible due to cost
Erin Calaine Inglis, Danilo Iannetta, Daniel A. Keir and Juan M. Murias
-incremental exercise, and the maximal lactate steady state (MLSS) of constant load exercise. 2 – 4 However, considerable debate persists regarding the physiological equivalence of these exercise landmarks and their interchangeability for identification of the critical intensity. 4 – 8 The correspondence between the
Ralph Beneke, Hermann Heck, Helge Hebestreit and Renate M Leithäuser
The value of blood lactate concentration (BLC) measured during incremental load tests in predicting maximal lactate-steady-state (MLSS) workload has rarely been investigated in children. In 17 children and 18 adults MLSS was 4.1 ± 0.9mmol 1.1. Workload at BLC of 3.0mmol 1.1 determined during an incremental load test explained about 80% of the variance (p < .001) and best predicted MLSS workload independent of age. This was despite the increase in power per time related to maximum incremental load test power being higher (p < .001) in children than in adults. The BLC response to given exercise intensities is faster in children without affecting MLSS.
Ralph Beneke and Renate M. Leithäuser
The maximal lactate steady state (MLSS) depicts the highest blood lactate concentration (BLC) that can be maintained over time without a continual accumulation at constant prolonged workload. In cycling, no difference in the MLSS was combined with lower power output related to peak workload (IMLSS) at 100 than at 50 rpm. MLSS coincides with a respiratory exchange ratio (RER) close to 1. Recently, at incremental exercise, an RER of 1 was found at similar workload and similar intensity but higher BLC at 100 than at 50 rpm. Therefore, the authors reassessed a potential effect of cycling cadences on the MLSS and tested the hypothesis that the MLSS would be higher at 105 than at 60 rpm with no difference in IMLSS in a between-subjects design (n = 16, age 25.1 ± 1.9 y, height 178.4 ± 6.5 cm, body mass 70.3 ± 6.5 kg vs n = 16, 23.6 ± 3.0 y, 181.4 ± 5.6 cm, 72.5 ± 6.2 kg; study I) and confirmed these findings in a within-subject design (n = 12, 25.3 ± 2.1 y, 175.9 ± 7.7 cm, 67.8 ± 8.9 kg; study II). In study I, the MLSS was lower at 60 than at 105 rpm (4.3 ± 0.7 vs 5.4 ± 1.0 mmol/L; P = .003) with no difference in IMLSS (68.7% ± 5.3% vs 71.8% ± 5.9%). Study II confirmed these findings on MLSS (3.4 ± 0.8 vs 4.5 ± 1.0 mmol/L; P = .001) and IMLSS (65.0% ± 6.8% vs 63.5% ± 6.3%; P = .421). The higher MLSS at 105 than at 60 rpm combined with an invariance of IMLSS and RER close to 1 at MLSS supports the hypothesis that higher cadences can induce a preservation of carbohydrates at given BLC levels during low-intensity, high-volume training sessions.
Naiandra Dittrich, Ricardo Dantas de Lucas, Ralph Beneke and Luiz Guilherme Antonacci Guglielmo
The purpose of this study was to determine and compare the time to exhaustion (TE) and the physiological responses at continuous and intermittent (ratio 5:1) maximal lactate steady state (MLSS) in well-trained runners. Ten athletes (32.7 ± 6.9 y, VO2max 61.7 ± 3.9 mL · kg−1 · min−1) performed an incremental treadmill test, three to five 30-min constant-speed tests to determine the MLSS continuous and intermittent (5 min of running, interspaced by 1 min of passive rest), and 2 randomized TE tests at such intensities. Two-way ANOVA with repeated measures was used to compare the changes in physiological variables during the TE tests and between continuous and intermittent exercise. The intermittent MLSS velocity (MLSSint = 15.26 ± 0.97 km/h) was higher than in the continuous model (MLSScon = 14.53 ± 0.93 km/h), while the TE at MLSScon was longer than MLSSint (68 ± 11 min and 58 ± 15 min, P < .05). Regarding the cardiorespiratory responses, VO2 and respiratory-exchange ratio remained stable during both TE tests while heart rate, ventilation, and rating of perceived exertion presented a significant increase in the last portion of the tests. The results showed a higher tolerance to exercising during MLSScon than during MLSSint in trained runners. Thus, the training volume of an extensive interval session (ratio 5:1) designed at MLSS intensity should take into consideration this higher speed at MLSS and also the lower TE than with continuous exercise.
Joanne R. Williams and Neil Armstrong
This investigation set out to estimate exercise intensity and blood lactate corresponding to the maximal lactate steady state (MLaSS) and also examined the relationship between performance at the MLaSS with performance at fixed blood lactate reference values of 2.5 and 4.0 mmol•1−1. Cardiopulmonary responses at peak treadmill exercise and blood lactate reference values were measured in 10 boys and 8 girls ages 13-14 years. The 2.5 mmol•11 reference value represented 84±7% peak VO2 in boys and 82±6% peak VO2 in girls. Corresponding values at the 4.0 mmol•1−1 level were 93±6% and 90±5% peak VO2. MLaSS occurred at 77±7% peak VO2 in boys and 76±7% peak VO2 in girls. Blood lactate at the MLaSS was 2.1±0.5 mmol•l−1 in boys and 2.3±0.6 mmol•l−1 in girls. Cardiopulmonary and heart rate responses at the MLaSS were not significantly different from corresponding responses at the 2.5 mmol•l−1 reference value. In contrast, cardiopulmonary responses at the 4.0 mmol•l−1 reference level were significantly higher than those at the MLaSS. These data indicate that a 2.5 mmol•l−1 criterion for assessing aerobic performance in children may be the most appropriate.
Billy Sperlich, Christoph Zinner, David Trenk and Hans-Christer Holmberg
To examine whether a 3-min all-out test can be used to obtain accurate values for the maximal lactate steady state (v MLSS) and/or peak oxygen uptake (VO2peak) of well-trained runners.
The 15 male volunteers (25 ± 5 y, 181 ± 6 cm, 76 ± 7 kg, VO2peak 69.3 ± 9.5 mL · kg−1 · min−1) performed a ramp test, a 3-min all-out test, and several submaximal 30-min runs at constant paces of v END (mean velocity during the last 30 s of the 3-min all-out test) itself and v END +0.2, +0.1, –0.1, –0.2, –0.3, or –0.4 m/s.
v MLSS and v END were correlated (r = .69, P = .004), although v MLSS was lower (mean difference: 0.26 ± 0.32 m/s, 95% CI –.44 to –.08 m/s, P = .007, effect size = 0.65). The VO2peak values derived from the ramp and 3-min all-out tests were not correlated (r = .41, P = .12), with a mean difference of 523 ± 1002 mL (95% CI –31 to 1077 mL).
A 3-min all-out test does not provide a suitable measure of v MLSS or VO2peak for well-trained runners.
David Michael Morris and Rebecca Susan Shafer
The authors sought to compare power output at blood lactate threshold, maximal lactate steady state, and pH threshold with the average power output during a simulated 20-km time trial assessed during cycle ergometry. Participants (N = 13) were trained male and female cyclists and triathletes, all permanent residents at moderate altitude (1,525–2,225 m). Testing was performed at 1,525 or 1,860 m altitude. Power outputs were determined during a simulated 20-km time trial (PTT), at blood pH threshold (PpHT), at maximal lactate steady state (PMLSS), and at blood lactate threshold determined by 2 methods: the highest power output that did not result in consecutive and continued increases in blood lactate concentrations from exercising baseline (PLT) and the highest power output that did not result in consecutive and continued increases of ≥1 mmol/L in blood lactate concentrations from exercising baseline (PLT1). PLT, PLT1, and PMLSS were all significantly lower than PpHT (p < .05) and PTT (p < .05). No significant difference was observed between PpHT and PTT (p > .05). Significant correlations were observed between each of the metabolic variables, PLT, PLT1, PMLSS, and PpHT, compared with PTT (p < .05). The authors conclude that, of the 4 metabolic variables, only PpHT offered an accurate reflection of PTT.