High-frequency whole-body vibration activates tonic vibration reflex

Area of Science:

• Neurology
• Biomechanics
• Exercise Physiology

Background:

• The tonic vibration reflex (TVR) is a stretch reflex elicited by sustained vibration.
• Whole-body vibration (WBV) is increasingly used in rehabilitation and training, but its effect on TVR is not fully understood.
• Understanding WBV's impact on neuromuscular responses like TVR is crucial for optimizing its application.

Purpose of the Study:

• To investigate whether high-frequency whole-body vibration (HF-WBV) can elicit the tonic vibration reflex (TVR).
• To compare the reflex responses to HF-WBV, low-frequency WBV (LF-WBV), and direct Achilles tendon vibration.

Main Methods:

• Seven healthy volunteers participated in the study.
• Soleus muscle TVR was elicited using direct Achilles tendon vibration (100-150 Hz).
• Surface electromyography recorded soleus muscle activity during quiet standing with HF-WBV (100-150 Hz) and LF-WBV (30-40 Hz).
• The cumulative average method determined reflex latencies.

Main Results:

• Reflex latency for direct Achilles tendon vibration (TVR) was 35.6±5.9 ms.
• Reflex latency for HF-WBV was 34.8±6.2 ms, not significantly different from TVR (p=0.526).
• Reflex latency for LF-WBV was significantly longer at 42.8±3.4 ms compared to both TVR (p=0.001) and HF-WBV (p=0.002).

Conclusions:

• High-frequency whole-body vibration (100-150 Hz) successfully activates the tonic vibration reflex in the soleus muscle.
• The neuromuscular response to HF-WBV is comparable to direct tendon vibration.
• Low-frequency WBV elicits a delayed reflex response, suggesting different underlying mechanisms.