Statistical evidence consistent with two lactate turnpoints during ramp exercise

Morton, R. Hugh; Fukuba, Yoshiyuki; Banister, E. W.; Walsh, M.L.; Kenny, C.T.C.; Cameron, B. J.

doi:10.1007/bf00865410

Cited by 15 publications

(6 citation statements)

References 27 publications

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“…The minimum duration necessary at each stage should be controlled for untrained and recreational athletes in further studies. Graduations with WL increment sizes of 40 or 50 W are sucient for lactate thresholds that are to be calculated using mathematical modelling and curve-®tting techniques (Hughson et al 1987;Berg et al 1990;Cheng et al 1992;Morton et al 1994). If QSS criteria are not accomplished in these protocols the underestimation of WL-related lactate values also has to be calculated.…”

Section: Discussionmentioning

confidence: 99%

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Stage duration and increase of work load in incremental testing on a cycle ergometer

Stockhausen

Grathwohl

Bürklin

et al. 1997

European Journal of Applied Physiology

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Any variation of the test protocol for incremental testing (IT) in cycle ergometry may affect the accuracy of the determination of anaerobic threshold (AnT). For lactate threshold concepts, indicating the maximum lactate steady-state (max Lass), the formation of the quasi-steady-state (QSS=95% of steady-state level) is evident. Previous studies have not specified the time that it takes for blood lactate to stabilize following incremental changes in WL. The purpose of this study was to identify the minimum duration of exercise necessary to establish QSS following various increments in WL (10, 20, 30, 40 and 50 W). Eight male endurance-trained cyclists [relative maximal oxygen consumption = 64.8 (4.2) ml x kg(-1) x min(-1)] performed three different exercise tests on a cycle ergometer: (1) an exhaustive IT with a starting WL of 100 W, followed by 20-W increments every 3 min; (2) a threshold test with 20-W increments every 9 min to determine the MaxLaSS; and (3) five incremental exercise tests (from 100/110 W, with 20-W increments every 3 min) with a final 10-, 20-, 30-, 40- or 50- W increment lasting 10 min, at 10 W below MaxLaSS (T10-T50 experiments). The time constant of lactate kinetics (tau), the time constant of lactate elimination, and the time taken to elicite QSS, defined as 95% of the time taken to reach steady-state level (t95%), were calculated in the T10-T50 experiments. The tau and t95% increased significantly with WL increment size: the correlation was not linear. Smaller WL increments required proportionally longer durations. Mean (SD) t95% values (min:s) were 1:57 (0:27) (T10), 2:58 (0.16) (T20), 4:08 (0:23) (T30), 4:45 (0:45) (T40) and 5:06 (0:43) (T50). The application of these references in IT protocols may lead to an extension of total test duration, particularly with smaller increments. Therefore, lactate threshold modelling, the training status of the athletes and comparability with lactate measurements obtained during training events should be considered. IT protocols not accomplishing QSS criteria may effect an underestimation of WL-related lactate values and an overestimation of lactate thresholds, which indicate MaxLaSS, especially in highly trained athletes. This suggests that the establishment of an increment-size-dependent t95% may reduce protocol-related influences on AnT and standardize the use of the AnT in IT procedures in the training management of elite cyclists.

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Section: Discussionmentioning

confidence: 99%

“…This protocol is known to accomplish the criteria of QSS (Stockhausen et al 1994(Stockhausen et al , 1995. The AnT was estimated using the second turnpoint (LT2) in lactate concentration (Anuola and Rusko 1984;Ribeiro et al 1985;Morton et al 1994). …”

Section: Incremental Testmentioning

confidence: 99%

Stage duration and increase of work load in incremental testing on a cycle ergometer

Stockhausen

Grathwohl

Bürklin

et al. 1997

European Journal of Applied Physiology

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“…The rise of BL concentration during stepwise increase of workload is best described using a model with two turning points instead of continuous [10] or single breakpoint models [11]. A number of studies have identified the existence of two ventilatory thresholds or LTs during exercise to exhaustion.…”

Section: Energy Supply and Lactic Acid Production During Incremental Exercisementioning

confidence: 99%

Methodological approach to the first and second lactate threshold in incremental cardiopulmonary exercise testing

Binder

Wonisch

Corrà

et al. 2008

European Journal of Cardiovascular Prevention & Rehabilitat

366

347

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Determination of an 'anaerobic threshold' plays an important role in the appreciation of an incremental cardiopulmonary exercise test and describes prominent changes of blood lactate accumulation with increasing workload. Two lactate thresholds are discerned during cardiopulmonary exercise testing and used for physical fitness estimation or training prescription. A multitude of different terms are, however, found in the literature describing the two thresholds. Furthermore, the term 'anaerobic threshold' is synonymously used for both, the 'first' and the 'second' lactate threshold, bearing a great potential of confusion. The aim of this review is therefore to order terms, present threshold concepts, and describe methods for lactate threshold determination using a three-phase model with reference to the historical and physiological background to facilitate the practical application of the term 'anaerobic threshold'.

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“…In general, methods for determining the transition from aerobic to anaerobic metabolism are based on incremental exercise tests with exercise periods of 1-5 min (Beaver et al 1986;Cabbrera and Chizeck 1996;Cheng et al 1992;Davis et al 1983;Dickhuth et al 1999;Keul et al 1979;Kindermann et al 1979;Mader et al 1976;McLellan and Jacobs 1993;Morton et al 1994;Prusaczyk et al 1993;Ribeiro et al 1985;Stegmann et al 1981;Wasserman and McIlroy 1964;Wasserman and Whip 1975;Wasserman 1984). In addition, previous studies have pointed out that periods longer than 1-5 min are required to reach a steady state of LA (Foxdal et al 1996;Hughson et al 1987;Oyono-Enguelle et al 1990;Stegmann et al 1981;Uhrhausen et al 1993).…”

Section: Introductionmentioning

confidence: 98%

Accuracy of neuro-fuzzy logic and regression calculations in determining maximal lactate steady-state power output from incremental tests in humans

Smekal

Scharl

Duvillard

et al. 2002

European Journal of Applied Physiology

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The aim of this study was to employ neuro-fuzzy logic and regression calculations to determine the accuracy of prediction of the power output ( P) of the maximal lactate steady-state (MLSS) on a cycle ergometer calculated from the results of incremental tests. A group of 17 male and 17 female sports students underwent two incremental tests (a 1 min test T(1): initial exercise intensity 0.2 W x kg(-1) increasing 0.2 W x kg(-1) every minute; a 3 min test T(3): initial exercise intensity 0.6 W x kg(-1) increasing 0.6 W x kg(-1) every 3 min) and at least four constant-intensity tests of 30 min duration. Two models for MLSS calculation were developed using the data from T(1) and T(3), a forward stepwise linear regression model (REG) and a neuro-fuzzy model (FUZ). A group of 26 randomly selected subjects (model group, MG) were used to generate the REG and the FUZ models. The data from the remaining 8 subjects (4 men and 4 women; verifying group, VG) were used to verify the REG and FUZ models. The precision of the MLSS calculation in MG produced a better correlation when using data from T(1) (REG r=0.95, FUZ r=0.99) than data from T(3) (REG r=0.88, FUZ r=0.98). Our calculation models were confirmed using data from VG for T(1) (REG r=0.97, FUZ r=0.98) as well as for T(3) (REG r=0.97, FUZ r=0.97). Based on our subject population of young, healthy sport students, our results suggest that a single incremental test may be used for prediction of P at the MLSS using a cycle ergometer. Furthermore, the results from T(1) yielded higher correlations compared to T(3). Calculations from REG were similar to FUZ but the precision of REG and FUZ was better compared to calculations derived using data from a single threshold.

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Statistical evidence consistent with two lactate turnpoints during ramp exercise

Cited by 15 publications

References 27 publications

Stage duration and increase of work load in incremental testing on a cycle ergometer

Stage duration and increase of work load in incremental testing on a cycle ergometer

Methodological approach to the first and second lactate threshold in incremental cardiopulmonary exercise testing

Accuracy of neuro-fuzzy logic and regression calculations in determining maximal lactate steady-state power output from incremental tests in humans

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