Investigation of The Neural Drive During Vibration Exercise by High-density Surface-electromyography

Area of Science:

• Neuroscience
• Human Physiology
• Biomechanics

Background:

• Mechanical vibration can elicit the tonic vibration reflex (TVR) via direct muscle stimulation.
• Vibration exercise (VE) may also evoke TVR, indicated by spectral peaks in surface electromyography (sEMG).
• These spectral peaks are debated, with some attributing them to motion artifacts (MAs).

Purpose of the Study:

• To investigate motor unit (MU) activation patterns during VE.
• To clarify the origin of spectral peaks observed in sEMG during VE.

Main Methods:

• Low-intensity isometric contractions were performed with and without VE.
• High-density sEMG was recorded during contraction tasks.
• MU action potential (MUAP) trains were extracted via sEMG decomposition.
• Spectra of MUAP trains were analyzed and compared between conditions.

Main Results:

• Clear MU synchronization was observed during VE.
• Spectral peaks at the vibration frequency were confirmed.
• These peaks were primarily attributed to MU synchronization within the TVR loop.

Conclusions:

• VE induces MU synchronization, supporting the TVR mechanism.
• The spectral peaks in sEMG during VE are mainly caused by the TVR, not MAs.
• This study clarifies the physiological basis of sEMG findings during VE.