Planckian Power Spectral Densities from Human Calves during Posture Maintenance and Controlled Isometric Contractions

Area of Science:

• Biophysics
• Physiology
• Electromyography

Background:

• The relationship between muscle anatomy/physiology and electromyography activity (EMGA) is complex.
• Existing EMGA models struggle to explain physiological variables' behavior with changes in temperature or pH.
• Motor unit action potentials are proposed as electromagnetic resonant modes within the muscle.

Purpose of the Study:

• To model motor unit action potentials as electromagnetic resonant modes.
• To develop theoretical relationships explaining physiological variables' behavior with temperature and pH changes.
• To validate these relationships against experimental data.

Main Methods:

• Recorded EMGA during posture maintenance and isometric contractions.
• Fitted the power spectral density of EMGA with Planckian distribution.
• Inferred and compared theoretical relationships with experimental values.

Main Results:

• EMGA power spectral density was accurately fit by Planckian distributions.
• All nine inferred theoretical relationships were validated by experimental results.

Conclusions:

• Modeling motor unit action potentials as electromagnetic resonant modes is essential for predicting muscle physiological variables.
• This approach successfully explains relationships other models cannot.
• This framework offers new insights into muscle physiology and EMGA.