Frequency and Voluntary Contraction-Dependent Activation of Tonic Vibration Reflex and Bone Myoregulation Reflex

When vibration is applied, sensors inside the muscle send signals to the nervous system, leading to automatic muscle activation. In this research, vibration will be applied using different body postures (such as standing or semi-squatting) and different vibration frequencies to understand how body position and vibration intensity influence muscle responses. Muscle activity will be recorded using surface electrodes placed on the skin. All procedures are non-invasive, painless, and do not involve medication or surgery.

The goal of this study is to improve understanding of how whole-body vibration affects muscle and nerve function. The findings may contribute to future rehabilitation strategies

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Key information

Conditions

Whole Body Vibration

Age range

20 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Istanbul Physical Therapy and Rehabilitation Training Research Hospital

Istanbul, Bahcelievler, 34180, Turkey (Türkiye)

About this study

This study investigates how whole-body vibration (WBV) affects muscle reflex activity in healthy adults. Whole-body vibration will be delivered using a vibration platform that transmits mechanical oscillations through the lower limbs and trunk while participants maintain specific postures.

The primary objective is to examine how different vibration frequencies and different body postures influence reflex-related muscle activation. Secondary objectives include evaluating how vibration modifies neuromuscular excitability and the timing and magnitude of reflex responses.

Participants will be exposed to multiple experimental conditions across separate sessions. These conditions will include different postural tasks (such as upright standing and semi-squat) and different vibration frequencies, allowing comparison of how mechanical load distribution and sensory input alter reflex modulation. Each vibration application will last 15 seconds, and rest periods will be provided between trials to minimize fatigue and ensure measurement reliability.

Muscle activity will be recorded using surface electromyography (EMG) electrodes placed over the soleus muscle. Reflex responses under different postures and vibration frequencies will be recorded during vibration. Data processing and analysis will be performed offline after the experiment is completed.

This study is based on previous findings indicating that whole-body vibration can stimulate muscle spindle afferent receptors as well as osteocyte-related mechanoreceptors within bone tissue, thereby increasing afferent sensory input and transiently modulating spinal and supraspinal motor control mechanisms, including reflex excitability and motor unit recruitment patterns. By systematically varying posture and vibration frequency, the study aims to clarify how vibration-induced sensory input interacts with biomechanical and neural factors to shape reflex response behavior.

The findings obtained from this study are expected to contribute to a more effective and targeted use of whole-body vibration in neuromuscular training, balance rehabilitation, enhancement of movement performance, and support of bone health. Furthermore, the results are anticipated to provide a scientific basis for the development of optimized vibration-based intervention protocols that consider both neuromuscular and musculoskeletal effects in clinical and athletic settings.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Being between 20-40 years old
Volunteering to participate in the research

Exclusion criteria

Refusal to participate in the study
Intolerance to whole-body vibration (WBV)
History of vertigo
Presence of malignant disease
Presence of chronic systemic disease
Pregnancy

Treatment and study plan

Whole-body vibration

Device

Participants will receive whole-body vibration using a vibration platform under different frequency and posture conditions. Vibration will be applied in short bouts (e.g., 15 seconds per trial) with rest periods between trials to minimize fatigue. Reflex and muscle activity responses will be recorded during vibration using surface electromyography (EMG)

Primary outcomes

Latency of the soleus reflex during whole-body vibration

Time frame: Day 1 (During a single experimental session)

The primary outcome measure is the latency of the soleus reflex activated by whole-body vibration (WBV). Reflex latency will be calculated using a cumulative averaging method. The vibration stimulus will be recorded via an accelerometer mounted on the vibration platform (LIS344ALH; ±6 g; ECOPACK®, Mansfield, TX, USA). The onset of the mechanical stimulus and the onset of the reflex response will be identified using cumulative averaging. Reflex latency will be defined as the time interval between the onset of the mechanical stimulus and the onset of the reflex response detected on surface electromyography (EMG), and will be expressed in milliseconds (ms).

Sponsors and collaborators

Lead sponsor

Istanbul Physical Medicine Rehabilitation Training and Research Hospital

Other Gov

Registry information

Official study title

Whole-Body Vibration in Rehabilitation: Frequency and Voluntary Contraction-Dependent Activation of Tonic Vibration Reflex and Bone Myoregulation Reflex

Acronym: WBV-BMR

Important dates

Study start: 2025
Primary completion: 2026
Study completion: 2026
First posted: Feb 4, 2026
Registry last updated: Feb 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed