[Determination of Aerobic-anaerobic Transition in Working Muscle Using EMG and Near Infrared-Spectroscopy Data]

Area of Science:

• Exercise Physiology
• Biomedical Engineering
• Sports Science

Context:

• Determining the aerobic-anaerobic transition (AAT) is crucial for optimizing exercise intensity and training.
• Current methods for AAT assessment can be invasive or require specialized equipment.
• Non-invasive methods are needed for broader applicability in various exercise settings.

Purpose:

• To introduce and validate a novel method for evaluating the aerobic-anaerobic transition (AAT) during exercise.
• To assess the correlation between the identified AAT and established anaerobic threshold markers.
• To determine the applicability of the method to both large and small muscle group exercises.

Summary:

• A new method utilizes the relationship between deoxygenated hemoglobin (HHb) and electromyography (EMG) activity of the m. vastus lateralis to pinpoint the AAT during incremental exercise.
• Subjects performed bicycle and single-leg knee extension tests, both showing a characteristic peak in HHb to EMG activity at the AAT.
• A significant correlation (r = 0.78, p < 0.05) was found between the AAT load and the anaerobic threshold (blood lactate = 4 mmol/L) during cycling.

Impact:

• This method provides a non-invasive and reliable way to determine the aerobic-anaerobic transition (AAT) during exercise.
• It is applicable to both large muscle group activities (e.g., cycling) and localized small muscle group exercises.
• The findings contribute to a better understanding of exercise physiology and can inform training program design.