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Resting mechanomyography after aerobic exercise
William P S McKay1, Philip D Chilibeck, Karen E Chad
1Department of Anesthesia, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Summary
Muscle mechanical activity, measured by mechano-myographic (MMG) signals, remains elevated after exercise. This sustained MMG activity may explain some of the excess postexercise oxygen consumption (VO2) not accounted for by biochemical recovery alone.
Area of Science:
- Exercise Physiology
- Skeletal Muscle Physiology
- Biomedical Engineering
Background:
- Elevated oxygen consumption after exercise (EPOC) is partially unexplained by biochemical recovery processes.
- Muscle sounds, or mechano-myographic (MMG) activity, represent mechanical work in resting muscle.
- MMG activity has been proposed as a potential contributor to EPOC.
Purpose of the Study:
- To investigate if resting mechano-myographic (MMG) amplitude changes post-exercise.
- To determine if changes in MMG activity correlate with excess postexercise oxygen consumption (VO2).
Main Methods:
- Ten healthy young males underwent 30 minutes of cycling exercise at 70% peak VO2.
- Oxygen consumption (VO2) was measured via indirect calorimetry.
- Mechano-myographic (MMG) activity was recorded using accelerometers on the quadriceps for 5.5 hours post-exercise.
Main Results:
- Resting MMG amplitude was significantly elevated for 5.5 hours after exercise (p < 0.05).
- Both MMG activity and VO2 exhibited exponential decay post-exercise.
- The decay time constants for MMG and VO2 were similar (7.2 min and 7.4 min, respectively).
Conclusions:
- Skeletal muscle exhibits significant mechanical activity for an extended period following exercise.
- This post-exercise mechanical muscle activity likely contributes to excess postexercise oxygen consumption (EPOC).
- MMG monitoring offers a novel approach to understanding EPOC components.