Document Detail


Stage duration and increase of work load in incremental testing on a cycle ergometer.
MedLine Citation:
PMID:  9349642     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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.
Authors:
W Stockhausen; D Grathwohl; C Bürklin; P Spranz; J Keul
Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of applied physiology and occupational physiology     Volume:  76     ISSN:  0301-5548     ISO Abbreviation:  Eur J Appl Physiol Occup Physiol     Publication Date:  1997  
Date Detail:
Created Date:  1997-11-26     Completed Date:  1997-11-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0410266     Medline TA:  Eur J Appl Physiol Occup Physiol     Country:  GERMANY    
Other Details:
Languages:  eng     Pagination:  295-301     Citation Subset:  IM; S    
Affiliation:
University Hospital Freiburg, Center for Internal Medicine, Department of Rehabilitation, Prevention and Sports Medicine, Germany.
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MeSH Terms
Descriptor/Qualifier:
Adult
Anaerobic Threshold / physiology
Bicycling / physiology
Exercise / physiology*
Exercise Test / standards*
Humans
Kinetics
Lactic Acid / blood
Male
Chemical
Reg. No./Substance:
50-21-5/Lactic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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