The Reliability of a Pre-Loaded Treadmill Time-Trial in Moderate Normobaric Hypoxia

Area of Science:

• Sports Science
• Exercise Physiology
• Altitude Training

Background:

• Assessing athletic performance in hypoxic conditions is crucial for training and competition.
• Normobaric hypoxia simulates high-altitude environments, impacting physiological responses.
• Reliability of performance tests under hypoxia is essential for accurate physiological monitoring.

Purpose of the Study:

• To evaluate the reliability of a 1,500-meter treadmill time trial performed in moderate normobaric hypoxia.
• To assess the consistency of physiological measurements during the hypoxic time trial.
• To determine the validity of this test for trained runners and triathletes.

Main Methods:

• Eight trained runners/triathletes completed three 1,500-meter time trials on a treadmill under normobaric hypoxia (simulated 2,500m altitude).
• Physiological variables including heart rate, arterial oxygen saturation, tissue oxygenation (StO2), and gas exchange (V˙O2, V˙CO2) were monitored.
• Running performance was assessed using time to completion, with reliability determined by coefficient of variation (CV) and intraclass correlation coefficient (ICC).

Main Results:

• Running performance demonstrated high reliability with a low CV (0.9%) and ICC (1).
• Most physiological variables exhibited good reliability (global CV ≤4.2%, ICC ≥0.87).
• Muscle and cerebral tissue oxygenation (StO2) showed lower reliability (CVs 10.4% and 4.1%, ICCs 0.70 and 0.82, respectively).

Conclusions:

• A 1,500-meter treadmill time trial in moderate normobaric hypoxia is a highly reliable performance test.
• The majority of monitored physiological variables are reliably measured during this hypoxic test.
• This test provides a dependable method for assessing performance and physiological responses in simulated altitude conditions.