Effect of test interruptions on blood lactate during constant workload testing

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• Constant load testing is a common method to assess exercise physiology.
• Understanding the impact of test interruptions (TI) on physiological markers is crucial for accurate assessment.
• Blood lactate concentration (BLC) and maximal lactate steady state (MLSS) are key indicators of endurance capacity.

Purpose of the Study:

• To investigate the influence of repetitive test interruptions (TI) during constant load testing on blood lactate concentration (BLC).
• To determine the effect of TI on maximal lactate steady state (MLSS), MLSS workload (P-MLSS), and relative MLSS intensity (Int-MLSS).

Main Methods:

• Nineteen male participants completed 30-minute constant load cycling tests under three conditions: no TI, 30-second TI, and 90-second TI every 5 minutes.
• Experiment A measured BLC at 30 minutes (BLC30) and the change in BLC during the final 20 minutes (DeltaBLC10-30).
• Experiment B determined MLSS, P-MLSS, and Int-MLSS using the three TI protocols.

Main Results:

• BLC30 and DeltaBLC10-30 were significantly lower with TI compared to no TI.
• MLSS remained unaffected by TI, but P-MLSS and Int-MLSS were significantly higher with TI.
• TI duration explained a substantial portion of the variance in BLC and MLSS-related variables.

Conclusions:

• Repetitive test interruptions decrease blood lactate accumulation during constant load tests.
• TI does not alter the true maximal lactate steady state.
• The MLSS is achieved at a higher workload (P-MLSS) and relative intensity (Int-MLSS) when test interruptions are applied.