Peripheral fatigue: new mechanistic insights from recent technologies

Area of Science:

• Exercise Physiology
• Biophysics
• Muscle Physiology

Background:

• Peripheral fatigue arises from complex cellular and musculoskeletal interactions.
• Surface electromyography and force analysis are common methods for studying muscle fatigue.

Purpose of the Study:

• To review recent technological advancements in peripheral fatigue research.
• To provide mechanistic insights into the electrochemical and mechanical aspects of skeletal muscle fatigue.

Main Methods:

• Literature review of advanced technologies: laser diffraction, 31P magnetic resonance spectroscopy, shear-wave elastography, tensiomyography, myotonometry, mechanomyography, and high-density surface electromyography.
• Analysis of combined force and surface electromyography data.

Main Results:

• Cellular electrochemical and mechanical changes, including cross-bridge alterations and membrane depolarization, precede muscle-tendon unit stiffness reduction.
• Muscle fatigue is not uniform; functional compartmentalization helps maintain performance.
• Fatigue alters load distribution among synergistic muscles.

Conclusions:

• Understanding peripheral fatigue requires examining both cellular and whole-muscle responses.
• Emerging technologies offer new avenues for investigating muscle fatigue mechanisms and compensatory strategies at the single-fiber level.