WBV Reflex Latency and Mechanical Load

Overview

This study aims to investigate how the magnitude of mechanical loading affects reflex latency patterns induced by whole-body vibration (WBV). WBV can trigger two types of reflexes: the tonic vibration reflex (TVR) and the bone myoregulation reflex (BMR), which may be influenced by load-bearing condition. The study will include healthy adult volunteers aged 20-50 years. Reflex responses will be recorded from the soleus muscle using surface EMG during both WBV. Different conditions of mechanical loading (i.e., standing on one foot, both feet) and vibration frequencies (30-36 Hz) will be tested. The main outcome will be the latency of the reflex responses, which will help distinguish between TVR and BMR activation. The goal is to better understand how mechanical load modifies reflex response timing and to characterize the underlying afferent pathways. This knowledge may contribute to optimizing vibration-based rehabilitation strategies.

This study investigates how the magnitude of mechanical loading alters reflex latency patterns during whole-body vibration (WBV), focusing specifically on the tonic vibration reflex (TVR) and the bone myoregulation reflex (BMR). Experimental data suggest that WBV may activate different reflex mechanisms depending on the level of postural loading, frequency, and amplitude of the vibration. Previous studies have shown that low-amplitude WBV tends to activate TVR under voluntary contraction, while higher mechanical loads and neutral standing posture are more likely to induce BMR. Surface electromyography (sEMG) recordings will be obtained from the soleus muscle during vibration stimuli applied at different frequencies (30, 32, 34, and 36 Hz). Recordings will be taken under multiple loading conditions: standing on both feet, standing on one foot. Reflex latency will be calculated using cumulative averaging techniques, and data will be analyzed offline using Spike2 software. Findings from this study may contribute to a deeper understanding of reflex integration during vibratory stimulation and inform future neurorehabilitation protocols that utilize WBV as a therapeutic modality.