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Stage duration and increase of work load in incremental testing on a cycle ergometer
W Stockhausen1, D Grathwohl, C Bürklin
1University Hospital Freiburg, Center for Internal Medicine, Department of Rehabilitation, Prevention and Sports Medicine, Germany.
Summary
Determining the anaerobic threshold (AnT) in cycle ergometry requires careful protocol selection. This study found that smaller work rate increments necessitate longer exercise durations to achieve lactate stabilization, impacting AnT accuracy in elite cyclists.
Area of Science:
- Sports Science
- Exercise Physiology
- Biochemistry
Background:
- Accurate determination of anaerobic threshold (AnT) in cycle ergometry is crucial for training management.
- Variations in incremental testing (IT) protocols can affect AnT accuracy, particularly concerning lactate stabilization.
- Previous research has not established the exercise duration needed for blood lactate to stabilize after incremental work rate (WL) changes.
Purpose of the Study:
- To identify the minimum exercise duration required to achieve quasi-steady-state (QSS) lactate levels following various WL increments in endurance-trained cyclists.
- To analyze the relationship between WL increment size and the time needed for lactate kinetics to stabilize.
Main Methods:
- Eight male endurance-trained cyclists performed exhaustive IT, threshold tests, and specific incremental tests with varying WL increments (10-50 W) lasting 10 minutes.
- Calculated time constant of lactate kinetics (tau) and time to reach 95% of steady-state lactate level (t95%) during the T10-T50 experiments.
- Analyzed the correlation between WL increment size and t95%.
Main Results:
- The time constant of lactate kinetics (tau) and the time to reach QSS (t95%) significantly increased with larger WL increments, demonstrating a non-linear correlation.
- Smaller WL increments required proportionally longer exercise durations to achieve lactate stabilization.
- Mean t95% values ranged from 1:57 (10 W increment) to 5:06 (50 W increment).
Conclusions:
- IT protocols must account for increment-size-dependent stabilization times (t95%) to accurately determine AnT and maximum lactate steady-state (maxLass).
- Failure to achieve QSS criteria can lead to underestimation of WL-related lactate values and overestimation of lactate thresholds, especially in highly trained athletes.
- Standardizing AnT determination in IT procedures requires considering these findings for effective training management in elite cyclists.