Tendon reflex is suppressed during whole-body vibration

Area of Science:

• Neuromuscular Physiology
• Biomechanics
• Vibration Therapy Research

Background:

• The tendon reflex (T-reflex) is a fundamental measure of spinal reflex excitability.
• Whole body vibration (WBV) is increasingly used in various settings, but its precise effects on reflex pathways are not fully elucidated.

Purpose of the Study:

• To investigate the impact of whole body vibration (WBV) on the amplitude of the tendon reflex (T-reflex).
• To determine if WBV influences the excitability of the soleus muscle's stretch reflex pathway.

Main Methods:

• Fifteen healthy young adult males participated.
• Surface EMG of the soleus muscle and accelerometer data from the Achilles tendon were recorded.
• T-reflex was elicited via tapping before and during random WBV sessions at frequencies from 25-50Hz.

Main Results:

• A significant decrease in mean peak-to-peak (PP) T-reflex amplitude was observed during WBV compared to baseline (p<0.0001).
• Maximum PP amplitude also significantly decreased during WBV (p<0.0001).
• No significant changes in Achilles tendon acceleration due to tapping were found between conditions.

Conclusions:

• Whole body vibration (WBV) demonstrably suppresses the tendon reflex (T-reflex).
• This suppression suggests pre-synaptic inhibition of primary spindle afferents during WBV.
• Findings align with previous research on high-frequency tendon vibration effects on reflex pathways.