Whole-body Vibration, Healthy Volunteers (HV), Muscle Contraction, Postural Balance, Electromyography
Conditions
Keywords
Whole-Body Vibration, Tonic Vibration Reflex, Bone Myoregulation Reflex, Reflex Latency, Postural Reflexes, Surface Electromyography, Mechanical Loading, Healthy Volunteers, Neuromuscular Physiology
Brief summary
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.
Detailed description
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.
Interventions
DEVICEWhole-Body Vibration
Participants will receive whole-body vibration (WBV) at 30-36 Hz under different mechanical loading conditions (e.g., standing on one foot, both feet,). Vibration-induced reflex responses will be recorded from the soleus muscle using surface electromyography. The intervention is designed to evaluate latency differences between tonic vibration reflex (TVR) and bone myoregulation reflex (BMR) under controlled biomechanical scenarios.
Sponsors
Selim Sezikli
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
All participants receive the same sequence of whole-body vibration under different loading conditions. There is no randomization or control group. This is a single-arm, within-subject experimental design evaluating reflex latency under multiple biomechanical scenarios.
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Aged between 18 and 40 years * Healthy adult volunteers with no known neurological or musculoskeletal disorders * Able to provide informed consent * Willing to comply with the procedures of the study, including EMG and vibration exposure
Exclusion criteria
* History of any neurological condition (e.g., peripheral neuropathy, spinal cord injury, stroke) * Musculoskeletal injury or surgery involving the lower extremities * Use of medications affecting neuromuscular function * Pregnancy * Presence of implanted electronic devices (e.g., pacemaker) * Known intolerance to vibration exposure
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Reflex latency (milliseconds) in the soleus muscle during vibration stimulation | Day 1 (single-session, during each experimental condition) | Reflex latency will be calculated based on surface EMG recordings from the soleus muscle during whole-body vibration at frequencies of 30-36 Hz. Latency will be analyzed using cumulative averaging techniques and expressed in milliseconds. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| EMG amplitude of reflex response in the soleus muscle during vibration stimulation | Day 1 (single-session, during each experimental condition) | The magnitude of EMG response during whole-body vibration will be recorded from the soleus muscle. Reflex amplitude differences will be analyzed across various postural loading conditions to evaluate suppression or facilitation effects. |
| Reflex type classification (TVR vs BMR) based on latency and mechanical load | Day 1 (single-session, during each experimental condition) | Reflex responses will be categorized as tonic vibration reflex (TVR) or bone myoregulation reflex (BMR) based on latency values and mechanical loading condition. Classification will be supported by comparisons of reflex latency and EMG suppression patterns across experimental conditions. |
| Reflex latency variability under different mechanical loading conditions | Day 1 (single-session, during each experimental condition) | Variability in reflex latency will be assessed across different postural load conditions (e.g., single-leg, double-leg, prone) to determine how load magnitude influences the consistency of reflex timing. Standard deviation and coefficient of variation will be calculated for each condition. |
| Effect of vibration frequency on reflex latency and amplitude | Day 1 (single-session, during each experimental condition) | Reflex latency and EMG amplitude will be compared across vibration frequencies (30, 32, 34, and 36 Hz) to investigate frequency-dependent modulation of neuromuscular responses in the soleus muscle. |
Countries
Turkey (Türkiye)
Outcome results
None listed