Correlation between surface electromyogram, oxygen uptake and blood lactate concentration during dynamic leg...

Area of Science:

• Exercise Physiology
• Muscle Physiology
• Biomedical Engineering

Background:

• Limited data exist on the relationship between motor drive and oxygen uptake in contracting muscles.
• Understanding this adjustment is crucial for interpreting exercise responses and training adaptations.

Purpose of the Study:

• To examine the ratio of electromyography (EMG) energy to oxygen uptake (V(O2)) during cycling exercise.
• To investigate correlations between this ratio and the anaerobic threshold (V(O2)AT) and blood lactate concentration.
• To determine the influence of training and anaerobic metabolism on these adjustments.

Main Methods:

• Seven untrained and trained individuals performed progressive and constant-load cycling exercises.
• Root mean square (RMS) of EMG from the vastus lateralis muscle was recorded.
• V(O2), V(O2)AT, and peak blood lactate concentration were measured.

Main Results:

• The RMS/V(O2) ratio initially increased then decreased during exercise and recovery, despite rising V(O2).
• The rate of decrease in RMS/V(O2) correlated positively with its initial peak and negatively with V(O2)AT during progressive exercise.
• Training and reduced anaerobic metabolism attenuated changes in the RMS/V(O2) ratio.

Conclusions:

• The adjustment of motor drive to oxygen uptake is influenced by anaerobic muscle metabolism.
• Training status and reduced anaerobic metabolism play a significant role in modulating the EMG/V(O2) relationship.
• The magnitude of anaerobic muscle metabolism is key in regulating motor drive adjustments during exercise.