Effects of stage duration in incremental running tests on physiological variables

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• Incremental running tests are common for assessing physiological responses.
• Stage duration in these tests can influence physiological variable measurements.
• Understanding these effects is vital for accurate performance assessment.

Purpose of the Study:

• To investigate the impact of varying stage durations (1, 3, and 6 minutes) in incremental running tests on physiological variables.
• To determine the optimal stage duration for measuring maximal lactate steady state (maxLASS) and its corresponding speed.
• To compare treadmill-derived maxLASS speed with outdoor running performance.

Main Methods:

• Eight well-trained runners completed incremental running tests with 1, 3, and 6-minute stages.
• A separate test involved 15-minute stages at speeds relative to the speed at 4 mmol/l blood lactate (V4) to determine maxLASS.
• Subjects also performed a 5km outdoor run at their determined maxLASS speed.

Main Results:

• Maximal running speed (Vmax) was significantly lower with longer stage durations (6-min and 3-min) compared to 1-min stages.
• Peak oxygen uptake (VO2) and peak heart rate were not significantly different across stage durations.
• The speed at 4 mmol/l blood lactate (V4) was significantly lower in the 6-min stage protocol compared to the 3-min protocol.
• MaxLASS could be reliably estimated using V4 from the 6-min stage protocol.

Conclusions:

• Stage duration has minimal impact on peak physiological measures like VO2 and heart rate during incremental running.
• Accurate assessment of blood lactate concentration and maxLASS speed requires a minimum stage duration of 6 minutes.
• Treadmill-based maxLASS estimation is comparable to outdoor running performance.