Healthy AdultNCT07408570
FREQUENCY-DEPENDENT SOLEUS REFLEX MODULATION DURING WHOLE-BODY VIBRATION
A study testing whole body vibration in people with Healthy Adult and Whole Body Vibration, run by Istanbul Physical Medicine Rehabilitation Training and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
Exposure to microgravity leads to pronounced impairments in neuromuscular control, postural stability, and spinal reflex regulation that cannot be attributed to muscle atrophy alone. Read more about this study
- Who is it for?
- Ages 20 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Adult, Whole Body Vibration
- What is being tested?
- whole body vibration
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 27 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 30 Nov 2025to 30 Jun 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy adults aged between 20 and 45 years,
- Absence of regular exposure to whole-body vibration (WBV) training.
Who cannot join
- A history of intolerance to whole-body vibration,
- Vertigo history,
- Any medical or neurological condition that could be exacerbated by vibratory stimulation.
- All participants will provide written informed consent prior to participation.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
Istanbul Pmr Training Hospital
Bahçelievler, Istanbul, 34197
About this study
Official title: FREQUENCY- DEPENDENT MODULATION OF SOLEUS REFLEX RESPONSES DURING WHOLE BODY- VIBRATION IMPLICATIONS FOR PORPELASTIC BOBE MYOREGULATION UNDER GRAVITATIONAL LOADING
Exposure to microgravity leads to pronounced impairments in neuromuscular control, postural stability, and spinal reflex regulation that cannot be attributed to muscle atrophy alone. Rather, these deficits point to a disruption of load-dependent sensorimotor mechanisms and highlight the essential role of gravitational loading of the skeleton as a critical source of sensory input for spinal motor control.
Spinal reflex behavior during upright stance has traditionally been explained primarily by muscle spindle-mediated pathways. However, this framework does not fully account for the reflex alterations observed under conditions of altered mechanical loading, including microgravity, prolonged unloading, or exposure to vibration. In parallel, advances in bone biology have identified osteocytes within the lacuno-canalicular system as highly sensitive mechanosensors that preferentially respond to dynamic loading and changes in strain rate. This insight has given rise to the concept of bone myoregulation, in which bone-derived mechanosensory signals contribute to the modulation of spinal excitability.
Read more
A defining characteristic of this process is the poroelastic nature of bone tissue. As a fluid-saturated porous medium, bone exhibits frequency-dependent mechanical behavior, such that oscillatory loading modifies both the temporal profile and magnitude of interstitial fluid flow within the lacuno-canalicular network. As a result, loading frequency is expected to influence not only the timing of reflex responses but also their amplitude. Whole-body vibration offers a controlled experimental paradigm to probe these frequency-dependent, load-sensitive mechanisms in humans.
Accordingly, the aim of the present study was to identify the whole-body vibration frequency band that most effectively induces soleus reflex responses during quiet standing, considering both reflex latency and response amplitude. Investigators hypothesized that these responses would display frequency-dependent behavior consistent with poroelastic bone-mediated myoregulation and would be modulated by individual anthropometric characteristics, with potential implications for vibration-based countermeasures under altered gravitational loading.
Read the detailed description
Experimental Procedure At the beginning of the experiment, participants will perform three repetitions of maximal voluntary plantarflexion (heel-rise) to determine maximal electromyographic (EMG) activity of the soleus muscle. These recordings will be used for normalization and reference purposes.
Subsequently, whole-body vibration will be applied at 13 different frequencies ranging from 25 to 49 Hz (25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, and 49 Hz). The order of vibration frequencies will be randomized for each participant to minimize order effects.
Whole-Body Vibration Protocol Participants will stand upright in an anatomically neutral position on the vibration platform and will be allowed to lightly hold the device's handrail to maintain balance without providing mechanical support. Vibration amplitude will be set at 2 mm. Each frequency condition will be applied for 15 s, with a 10 s rest period between trials. All WBV applications will be delivered using a Power Plate Pro5 device (Power Plate International Ltd., UK).
Surface Electromyography Recording Surface electromyography (sEMG) will be recorded from the left soleus muscle using bipolar Ag/AgCl electrodes (Redline®, Istanbul, Türkiye; 10-mm diameter, 4-cm interelectrode distance) aligned with the muscle fibers following appropriate skin preparation (impedance <10 kΩ). The electrodes will be placed over the lateral belly of the soleus muscle, with the ground electrode positioned on the right lateral malleolus. The sEMG signals will be amplified (×1000), band-pass filtered between 10 and 1,000 Hz, and sampled at 5,000 Hz.
EMG signals will be acquired using a CED 1902 Quad System MKIII amplifier and a CED Power 1401 MKII A/D converter and will be recorded with Spike2 software (version 7.20; Cambridge Electronic Design, UK). Signals will be stored for offline analysis. Frequency-domain analysis will be performed using fast Fourier transform (FFT) algorithms implemented in Spike2.
- Conditions
- Healthy Adult, Whole Body Vibration
- Being tested
- whole body vibration
- Keywords
- bone myoregulation reflex
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
whole body vibrationOther
Whole-Body Vibration Protocol Participants will stand upright in an anatomically neutral position on the vibration platform and will be allowed to lightly hold the device's handrail to maintain balance without providing mechanical support. Vibration amplitude will be set at 2 mm. Each frequency condition will be applied for 15 s, with a 10 s rest period between trials. All WBV applications will be delivered using a Power Plate Pro5 device (Power Plate International Ltd., UK).
| Study group | Role | What they receive |
|---|---|---|
| experimental group | Experimental | experimental group Receives: Other: whole body vibration |
What is being measured
The primary outcome is the main question the study is designed to answer.
1. WBV-evoked soleus reflex latency (ms)
Reflex latency will be defined as the time interval between the onset of whole-body vibration and the onset of the reflex-related EMG response in the soleus muscle. EMG onset will be identified as the point at which the rectified EMG signal exceeds the mean baseline activity by more than two standard deviations and remains above this threshold for at least 10 ms.
This measure will be used as an index of the temporal dynamics of load-sensitive mechanotransduction, consistent with the poroelastic bone-BMR framework.
Measured: 195 seconds
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Feb 2026
- Study start30 Nov 2025
- Primary completion26 Feb 2026 (estimated)
- Study completion30 Jun 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy AdultStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Screening
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- * A history of intolerance to whole-body vibration, * Vertigo history, * Any medical or neurological condition that could be exacerbated by vibratory stimulation. All participants will provide written informed consent prior to participation.
- Masking
- None (open label)
- Enrolment
- 27 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Istanbul Physical Medicine Rehabilitation Training and Research Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Feride Sabırlı, Istanbul Physical Medicine Rehabilitation Training and Research Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07408570
- Sponsor's protocol ID
- 2025-78
- Status last verified
- Feb 2026
- First submitted
- 26 Jan 2026
- Last updated
- 13 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 13 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- FREQUENCY- DEPENDENT MODULATION OF SOLEUS REFLEX RESPONSES DURING WHOLE BODY- VIBRATION IMPLICATIONS FOR PORPELASTIC BOBE MYOREGULATION UNDER GRAVITATIONAL LOADING
- ClinicalTrials.gov ID
- NCT07408570
- Acronym / sponsor ID
- 2025-78
- Conditions
- Healthy Adult, Whole Body Vibration
- Keywords
- bone myoregulation reflex
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 27 participants (estimated)
- Lead sponsor
- Istanbul Physical Medicine Rehabilitation Training and Research HospitalOther government
- Study start
- 30 Nov 2025 (actual)
- Primary completion
- 26 Feb 2026 (estimated)
- Study completion
- 30 Jun 2026 (estimated)
- First posted
- 13 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Exposure to microgravity leads to pronounced impairments in neuromuscular control, postural stability, and spinal reflex regulation that cannot be attributed to muscle atrophy alone. Rather, these deficits point to a disruption of load-dependent sensorimotor mechanisms and highlight the essential role of gravitational loading of the skeleton as a critical source of sensory input for spinal motor control.
Spinal reflex behavior during upright stance has traditionally been explained primarily by muscle spindle-mediated pathways. However, this framework does not fully account for the reflex alterations observed under conditions of altered mechanical loading, including microgravity, prolonged unloading, or exposure to vibration. In parallel, advances in bone biology have identified osteocytes within the lacuno-canalicular system as highly sensitive mechanosensors that preferentially respond to dynamic loading and changes in strain rate. This insight has given rise to the concept of bone myoregulation, in which bone-derived mechanosensory signals contribute to the modulation of spinal excitability.
A defining characteristic of this process is the poroelastic nature of bone tissue. As a fluid-saturated porous medium, bone exhibits frequency-dependent mechanical behavior, such that oscillatory loading modifies both the temporal profile and magnitude of interstitial fluid flow within the lacuno-canalicular network. As a result, loading frequency is expected to influence not only the timing of reflex responses but also their amplitude. Whole-body vibration offers a controlled experimental paradigm to probe these frequency-dependent, load-sensitive mechanisms in humans.
Accordingly, the aim of the present study was to identify the whole-body vibration frequency band that most effectively induces soleus reflex responses during quiet standing, considering both reflex latency and response amplitude. Investigators hypothesized that these responses would display frequency-dependent behavior consistent with poroelastic bone-mediated myoregulation and would be modulated by individual anthropometric characteristics, with potential implications for vibration-based countermeasures under altered gravitational loading.
Detailed description
Experimental Procedure At the beginning of the experiment, participants will perform three repetitions of maximal voluntary plantarflexion (heel-rise) to determine maximal electromyographic (EMG) activity of the soleus muscle. These recordings will be used for normalization and reference purposes.
Subsequently, whole-body vibration will be applied at 13 different frequencies ranging from 25 to 49 Hz (25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, and 49 Hz). The order of vibration frequencies will be randomized for each participant to minimize order effects.
Whole-Body Vibration Protocol Participants will stand upright in an anatomically neutral position on the vibration platform and will be allowed to lightly hold the device's handrail to maintain balance without providing mechanical support. Vibration amplitude will be set at 2 mm. Each frequency condition will be applied for 15 s, with a 10 s rest period between trials. All WBV applications will be delivered using a Power Plate Pro5 device (Power Plate International Ltd., UK).
Surface Electromyography Recording Surface electromyography (sEMG) will be recorded from the left soleus muscle using bipolar Ag/AgCl electrodes (Redline®, Istanbul, Türkiye; 10-mm diameter, 4-cm interelectrode distance) aligned with the muscle fibers following appropriate skin preparation (impedance <10 kΩ). The electrodes will be placed over the lateral belly of the soleus muscle, with the ground electrode positioned on the right lateral malleolus. The sEMG signals will be amplified (×1000), band-pass filtered between 10 and 1,000 Hz, and sampled at 5,000 Hz.
EMG signals will be acquired using a CED 1902 Quad System MKIII amplifier and a CED Power 1401 MKII A/D converter and will be recorded with Spike2 software (version 7.20; Cambridge Electronic Design, UK). Signals will be stored for offline analysis. Frequency-domain analysis will be performed using fast Fourier transform (FFT) algorithms implemented in Spike2.
Study design
- Primary purpose
- Screening
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- * A history of intolerance to whole-body vibration, * Vertigo history, * Any medical or neurological condition that could be exacerbated by vibratory stimulation. All participants will provide written informed consent prior to participation.
| Arm | Type | Receives |
|---|---|---|
| experimental group | Experimental | Other: whole body vibrationexperimental group |
Who may qualify
- Ages
- 20 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Healthy adults aged between 20 and 45 years,
- Absence of regular exposure to whole-body vibration (WBV) training.
Key exclusion criteria (4 listed)
- A history of intolerance to whole-body vibration,
- Vertigo history,
- Any medical or neurological condition that could be exacerbated by vibratory stimulation.
- All participants will provide written informed consent prior to participation.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| whole body vibrationWhole-Body Vibration Protocol Participants will stand upright in an anatomically neutral position on the vibration platform and will be allowed to lightly hold the device's handrail to maintain balance without providing mechanical support. Vibration amplitude will be set at 2 mm. Each frequency condition will be applied for 15 s, with a 10 s rest period between trials. All WBV applications will be delivered using a Power Plate Pro5 device (Power Plate International Ltd., UK). | Other | experimental group |
Primary outcome
1. WBV-evoked soleus reflex latency (ms)
Time frame: 195 seconds
Reflex latency will be defined as the time interval between the onset of whole-body vibration and the onset of the reflex-related EMG response in the soleus muscle. EMG onset will be identified as the point at which the rectified EMG signal exceeds the mean baseline activity by more than two standard deviations and remains above this threshold for at least 10 ms. This measure will be used as an index of the temporal dynamics of load-sensitive mechanotransduction, consistent with the poroelastic bone-BMR framework.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Feb 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing whole body vibration in people with Healthy Adult and Whole Body Vibration, run by Istanbul Physical Medicine Rehabilitation Training and Research Hospital at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 13 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
1. WBV-evoked soleus reflex latency (ms) (time frame: 195 seconds). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Feb 2026.