A Pilot Study Using Entropy as a Noninvasive Assessment of Running

Area of Science:

• Sports Science
• Biomechanical Analysis
• Exercise Physiology

Background:

• Running performance depends on biomechanical and physiological interactions.
• Accelerometers offer a noninvasive method to assess running mechanics, training status, and progression.
• Current methods for monitoring physiological load during exercise can be invasive or cumbersome.

Purpose of the Study:

• To develop and validate a method using accelerometers to assess running regularity.
• To estimate oxygen uptake (V̇O₂) and blood lactate ([La]_b) based on accelerometer data.
• To provide a noninvasive tool for monitoring athlete training status and fatigue.

Main Methods:

• Male adolescent endurance athletes underwent incremental submaximal aerobic testing.
• Oxygen uptake (V̇O₂) and blood lactate ([La]_b) were measured throughout the test.
• Triaxial accelerometers recorded motion on the shank and lower back, with RMS and SampEn calculated.

Main Results:

• Significant positive correlations (r = .43-.87) were found between acceleration/entropy variables and [La]_b/V̇O₂.
• Shank acceleration's RMS showed the strongest relation to both physiological variables.
• Trunk-mounted accelerometer's vertical acceleration SampEn strongly correlated with V̇O₂ (r = .76, P < .01).

Conclusions:

• Accelerometer-based analysis of running complexity can assess gait variability.
• This noninvasive method effectively tracks V̇O₂ and [La]_b levels.
• The technique allows for monitoring fatigue and training readiness in adolescent athletes.