Osteoporosis PostmenopausalNCT07253493
Effect of Mechanical Loading and Bone Loss on Motor Neuron Activity-H-Reflex Relationship
A study testing H-reflex and Bone myoregulation reflex in people with Osteoporosis Postmenopausal, run by Istanbul Physical Medicine Rehabilitation Training and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
Weight-bearing exercises (e.g., running, jumping, whole-body vibration) are widely practiced due to their beneficial effects on bone development and their role in the prevention and treatment of osteoporosis. Read more about this study
- Who is it for?
- Ages 18 to 65 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Osteoporosis Postmenopausal
- What is being tested?
- H-reflex and Bone myoregulation reflex
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 24 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 18 Nov 2025to Apr 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 18 to 65 years
- Women only
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Being in the postmenopausal period
- For the osteoporosis group: having femoral osteoporosis (femoral neck or total femur T-score ≤ -2.5)
- For the control group: having no osteoporosis or osteopenia (femoral neck and total femur T-scores > -1, and L1-L4 and L2-L4 T-scores > -1)
- Being a volunteer
Who cannot join
- Receiving osteoporosis treatment
- Having a peripheral or central nervous system disorder (e.g., stroke, polyneuropathy, radiculopathy, entrapment neuropathy, etc.)
- Having acquired or hereditary muscle diseases (myopathies)
- Having active painful lower extremity pathologies (e.g., osteoarthritis, inflammatory joint diseases, etc.)
- Having cardiac arrhythmias
- Having a history of other metabolic bone diseases
- Having skin lesions at the electrode placement sites on the lower extremities
- Being older than 65 years
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, 1 recruiting
- Recruiting
Istanbul Physical Medicine Rehabilitation Training & Research Hospital
Bahçelievler, Istanbul, 34180
Fuat Orhun Alayoğlu, Attending Doctor, 05348431984, f.orhunalayoglu@gmail.com
İlhan Karacan, Prof. Dr., 0532 700 5361, mdilhankaracan@gmail.com
About this study
Official title: The Effect of Mechanical Loading and Bone Loss on the Relationship Between Motor Neuron Pool Activity and H-Reflex Amplitude
Weight-bearing exercises (e.g., running, jumping, whole-body vibration) are widely practiced due to their beneficial effects on bone development and their role in the prevention and treatment of osteoporosis. However, the underlying neuroregulatory mechanisms responsible for these positive effects have not yet been fully understood. Two main neuromodulatory mechanisms have been proposed in the literature: (i) spinal reflexes originating from muscle spindles (stretch reflex, tonic vibration reflex), and (ii) the bone myoregulation reflex (BMR) based on load-sensitive osteocytes.
It is well established that increased voluntary contraction and the associated rise in background EMG activity, that is, motor neuron pool activity, enhance muscle spindle-based reflex responses (such as the H-reflex and tendon reflex). In contrast, it has been demonstrated that the H-reflex is suppressed during bone-loading activities such as single-leg stance, jumping, or whole-body vibration.
Read more
This study is based on two hypotheses:
- As mechanical loading increases, Ia inhibitory effects intensify, leading to greater H-reflex suppression.
- During whole-body vibration, the H-reflex is suppressed due to Ia inhibition.
If this inhibition originates from load-sensitive receptors-osteocytes-and thus from the BMR, then in osteoporosis, where osteocyte number and function are reduced, H-reflex suppression will be diminished.
The aim of this research is to test these hypotheses. Confirmation of these assumptions would suggest that reflex control during weight-bearing exercise occurs predominantly through osteocyte-mediated BMR mechanisms rather than muscle spindle-based mechanisms such as the stretch or tonic vibration reflex.
Read the detailed description
EMG and Force Data Acquisition
Surface EMG signals from the soleus muscle, accelerometer data from the whole-body vibration platform, and force sensor data will be collected at a 2 kHz sampling rate using a data acquisition system (CED 3601 Power 1401 MKII digital-to-analogue converter and CED 1902 Quad System MKIII amplifier). Data analysis will be performed using Spike2 version 7.20 software.
Subjects will be tested while standing on both feet. A force load cell (FC2231-0000-0100-L Compression Load Sensor, France) will be placed under the right heel of the subjects to obtain real-time readings of the weight applied to the right heel.
Before attaching the electrodes, any hair on the skin will be shaved, and the skin will be cleaned with alcohol wipes to remove surface oils. An ECG gel will be applied to increase skin conductivity.
A PowerPlate Pro5 (London, UK) device will be used to apply whole-body vibration.
________________________________________ H-reflex Measurement
A cathode electrode (1 cm diameter round electrode) will be positioned over the tibial nerve in the right popliteal fossa, and an anode electrode (10 × 10 cm) will be placed over the suprapatellar area. Stimulation will be delivered using a constant-current stimulator [model DS7A, Digitimer Ltd, Hertfordshire, UK] with monophasic rectangular current pulses of 1 ms duration. The current intensity will start at 5 mA and will be incrementally increased. The intensity required to obtain the recruitment curve of the H-reflex and the maximum M-response (Mmax) will be determined. A current intensity that elicits an M-response of 10-30% of Mmax will be used to minimize variations in H-reflex amplitude depending on stimulus intensity.
H-reflex will be measured in six different conditions. First, subjects will be asked to place 10%, 30%, 50%, 70%, and 100% of their body weight on their right leg in a random order. A monitor displaying real-time feedback of the weight applied to the right leg will be placed in front of the subjects to help stabilize the target load. The target weight percentage will be indicated on the monitor. For each load condition, 10 H-reflex measurements will be obtained at 10-second intervals.
Afterward, a 1-minute-long 30 Hz low-amplitude (1.2 mm) whole-body vibration will be applied to the subjects, and the H-reflex will be measured every 5 seconds.
To assess motor neuron activity, the EMG activity in the 100 ms preceding the electrical stimulation will be quantified as RMS amplitude.
________________________________________ Bone Myoregulation Reflex
10-second long low-amplitude (1.2 mm) whole-body vibrations of 30 Hz, 32 Hz, 34 Hz, and 36 Hz will be applied to the subjects. Cumulative averaging method will be used to measure latency of bone myoregulation reflex.
________________________________________ Sample Size Calculation
In this study, the H-reflex amplitude will be measured under five different loading conditions and during whole-body vibration in two groups. Assuming an effect size (partial eta squared) of 0.06, an alpha error level of 0.05, and a statistical power of 0.9, the minimum required sample size will be calculated as 12 subjects per group, for a total of 24 subjects. The sample size calculation will be performed using G*Power version 3.1.9.4 (Franz Faul, Universität Kiel, Germany).
________________________________________ Statistical Analysis
The normality of data distribution will be assessed using the Shapiro-Wilk test. Variables showing a normal distribution will be presented as mean ± standard deviation, whereas non-normally distributed variables will be summarized as median (interquartile range).
H-reflex amplitude and background EMG activity measured under five different loading conditions and during whole-body vibration will be compared using repeated-measures analysis of variance (ANOVA) when the assumption of normality is met. Tukey or Bonferroni post-hoc tests will be applied when appropriate. When the normality assumption is violated, the Friedman test will be used, and pairwise comparisons will be performed using the Wilcoxon test. Bonferroni correction will be applied for post-hoc analyses.
All statistical analyses will be conducted using SPSS software (version 18.0; SPSS Inc., Chicago, IL, USA).
- Conditions
- Osteoporosis Postmenopausal
- Being tested
- H-reflex, Bone myoregulation reflex
- Keywords
- H-reflex, osteoporosis, whole-body vibration, mechanical load, osteocyte, bone myoregulation reflex, background EMG activity
- Medical subject headings
- Osteoporosis, Postmenopausal, Osteoporosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
H-reflexDiagnostic test
Also called Hoffmann's reflex
H-reflex will be measured during 5 different mechanical loads and whole body vibration.
Bone myoregulation reflexDiagnostic test
Bone myoregulation reflex will be measured by applying 10 seconds whole body vibration of 4 different frequencies.
| Study group | Role | What they receive |
|---|---|---|
| Postmenapausal femoral osteoporosis | Other | Subjects with diagnosed femoral osteoporosis will be in this arm. Femoral osteoporosis is defined as T-scores of -2.5 or lower in femoral neck or total femur obtained in dual energy x-ray absorptiometry.
Subjects will have their H-reflex amplitude measured in 6 different settings and will be applied 10 seconds whole-body vibration in 4 different frequencies to measure bone mroregulation reflex. Receives: Diagnostic Test: H-reflex; Diagnostic Test: Bone myoregulation reflex |
| Healthy control | Other | Subjects who do not have osteoporosis or osteopenia will be in this arm. Subjects in this group will have L1-L4, L2-L4, femoral neck and total femur T-scores of greater than -1 obtained in dual energy x-ray absorptiometry.
Subjects will have their H-reflex amplitude measured in 6 different settings and will be applied 10 seconds whole-body vibration in 4 different frequencies to measure bone mroregulation reflex. Receives: Diagnostic Test: H-reflex; Diagnostic Test: Bone myoregulation reflex |
What is being measured
The primary outcome is the main question the study is designed to answer.
H-reflex Amplitude
H reflex will be measured 10 times each in 5 different mechanical loads and during 1 minute whole-body vibration. Average amplitude of 10 measurements will be calculated.
Measured: During the day of testing
Secondary outcomes (1)
Bone myoregulation reflex latency
10 seconds whole-body vibration in 4 different frequencies will be applied to subjects. Cumulative averaging method will be used to calculate bone myoregulation reflex latency.
Measured: During the day of testing
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Nov 2025
- Study start18 Nov 2025
- Primary completionMar 2026 (estimated)
- Study completionApr 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Osteoporosis PostmenopausalStudies 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
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Single group
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 24 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Istanbul Physical Medicine Rehabilitation Training and Research Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Fuat Orhun Alayoglu, Istanbul Physical Medicine Rehabilitation Training and Research Hospital
- Investigators
- İlhan Karacan, Prof. Dr., Study chair, stanbul Physical Medicine Rehabilitation Training and Research Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07253493
- Sponsor's protocol ID
- MLBLHR
- Status last verified
- Nov 2025
- First submitted
- 19 Nov 2025
- Last updated
- 28 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All collected data will be shared
Study at a glance
From the registry record, last updated by the sponsor on 28 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Mechanical Loading and Bone Loss on the Relationship Between Motor Neuron Pool Activity and H-Reflex Amplitude
- ClinicalTrials.gov ID
- NCT07253493
- Acronym / sponsor ID
- MLBLHR
- Conditions
- Osteoporosis Postmenopausal
- Keywords
- H-reflex, osteoporosis, whole-body vibration, mechanical load, osteocyte, bone myoregulation reflex, background EMG activity
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 24 participants (estimated)
- Lead sponsor
- Istanbul Physical Medicine Rehabilitation Training and Research HospitalOther government
- Study start
- 18 Nov 2025 (actual)
- Primary completion
- Mar 2026 (estimated)
- Study completion
- Apr 2026 (estimated)
- First posted
- 28 Nov 2025 (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.
Weight-bearing exercises (e.g., running, jumping, whole-body vibration) are widely practiced due to their beneficial effects on bone development and their role in the prevention and treatment of osteoporosis. However, the underlying neuroregulatory mechanisms responsible for these positive effects have not yet been fully understood. Two main neuromodulatory mechanisms have been proposed in the literature: (i) spinal reflexes originating from muscle spindles (stretch reflex, tonic vibration reflex), and (ii) the bone myoregulation reflex (BMR) based on load-sensitive osteocytes.
It is well established that increased voluntary contraction and the associated rise in background EMG activity, that is, motor neuron pool activity, enhance muscle spindle-based reflex responses (such as the H-reflex and tendon reflex). In contrast, it has been demonstrated that the H-reflex is suppressed during bone-loading activities such as single-leg stance, jumping, or whole-body vibration.
This study is based on two hypotheses:
- As mechanical loading increases, Ia inhibitory effects intensify, leading to greater H-reflex suppression.
- During whole-body vibration, the H-reflex is suppressed due to Ia inhibition.
If this inhibition originates from load-sensitive receptors-osteocytes-and thus from the BMR, then in osteoporosis, where osteocyte number and function are reduced, H-reflex suppression will be diminished.
The aim of this research is to test these hypotheses. Confirmation of these assumptions would suggest that reflex control during weight-bearing exercise occurs predominantly through osteocyte-mediated BMR mechanisms rather than muscle spindle-based mechanisms such as the stretch or tonic vibration reflex.
Detailed description
EMG and Force Data Acquisition
Surface EMG signals from the soleus muscle, accelerometer data from the whole-body vibration platform, and force sensor data will be collected at a 2 kHz sampling rate using a data acquisition system (CED 3601 Power 1401 MKII digital-to-analogue converter and CED 1902 Quad System MKIII amplifier). Data analysis will be performed using Spike2 version 7.20 software.
Subjects will be tested while standing on both feet. A force load cell (FC2231-0000-0100-L Compression Load Sensor, France) will be placed under the right heel of the subjects to obtain real-time readings of the weight applied to the right heel.
Before attaching the electrodes, any hair on the skin will be shaved, and the skin will be cleaned with alcohol wipes to remove surface oils. An ECG gel will be applied to increase skin conductivity.
A PowerPlate Pro5 (London, UK) device will be used to apply whole-body vibration.
________________________________________ H-reflex Measurement
A cathode electrode (1 cm diameter round electrode) will be positioned over the tibial nerve in the right popliteal fossa, and an anode electrode (10 × 10 cm) will be placed over the suprapatellar area. Stimulation will be delivered using a constant-current stimulator [model DS7A, Digitimer Ltd, Hertfordshire, UK] with monophasic rectangular current pulses of 1 ms duration. The current intensity will start at 5 mA and will be incrementally increased. The intensity required to obtain the recruitment curve of the H-reflex and the maximum M-response (Mmax) will be determined. A current intensity that elicits an M-response of 10-30% of Mmax will be used to minimize variations in H-reflex amplitude depending on stimulus intensity.
H-reflex will be measured in six different conditions. First, subjects will be asked to place 10%, 30%, 50%, 70%, and 100% of their body weight on their right leg in a random order. A monitor displaying real-time feedback of the weight applied to the right leg will be placed in front of the subjects to help stabilize the target load. The target weight percentage will be indicated on the monitor. For each load condition, 10 H-reflex measurements will be obtained at 10-second intervals.
Afterward, a 1-minute-long 30 Hz low-amplitude (1.2 mm) whole-body vibration will be applied to the subjects, and the H-reflex will be measured every 5 seconds.
To assess motor neuron activity, the EMG activity in the 100 ms preceding the electrical stimulation will be quantified as RMS amplitude.
________________________________________ Bone Myoregulation Reflex
10-second long low-amplitude (1.2 mm) whole-body vibrations of 30 Hz, 32 Hz, 34 Hz, and 36 Hz will be applied to the subjects. Cumulative averaging method will be used to measure latency of bone myoregulation reflex.
________________________________________ Sample Size Calculation
In this study, the H-reflex amplitude will be measured under five different loading conditions and during whole-body vibration in two groups. Assuming an effect size (partial eta squared) of 0.06, an alpha error level of 0.05, and a statistical power of 0.9, the minimum required sample size will be calculated as 12 subjects per group, for a total of 24 subjects. The sample size calculation will be performed using G*Power version 3.1.9.4 (Franz Faul, Universität Kiel, Germany).
________________________________________ Statistical Analysis
The normality of data distribution will be assessed using the Shapiro-Wilk test. Variables showing a normal distribution will be presented as mean ± standard deviation, whereas non-normally distributed variables will be summarized as median (interquartile range).
H-reflex amplitude and background EMG activity measured under five different loading conditions and during whole-body vibration will be compared using repeated-measures analysis of variance (ANOVA) when the assumption of normality is met. Tukey or Bonferroni post-hoc tests will be applied when appropriate. When the normality assumption is violated, the Friedman test will be used, and pairwise comparisons will be performed using the Wilcoxon test. Bonferroni correction will be applied for post-hoc analyses.
All statistical analyses will be conducted using SPSS software (version 18.0; SPSS Inc., Chicago, IL, USA).
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Single group
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Postmenapausal femoral osteoporosis | Other | Diagnostic Test: H-reflex, Diagnostic Test: Bone myoregulation reflexSubjects with diagnosed femoral osteoporosis will be in this arm. Femoral osteoporosis is defined as T-scores of -2.5 or lower in femoral neck or total femur obtained in dual energy x-ray absorptiometry. Subjects will have their H-reflex amplitude measured in 6 different settings and will be applied 10 seconds whole-body vibration in 4 different frequencies to measure bone mroregulation reflex. |
| Healthy control | Other | Diagnostic Test: H-reflex, Diagnostic Test: Bone myoregulation reflexSubjects who do not have osteoporosis or osteopenia will be in this arm. Subjects in this group will have L1-L4, L2-L4, femoral neck and total femur T-scores of greater than -1 obtained in dual energy x-ray absorptiometry. Subjects will have their H-reflex amplitude measured in 6 different settings and will be applied 10 seconds whole-body vibration in 4 different frequencies to measure bone mroregulation reflex. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Being in the postmenopausal period
- For the osteoporosis group: having femoral osteoporosis (femoral neck or total femur T-score ≤ -2.5)
- For the control group: having no osteoporosis or osteopenia (femoral neck and total femur T-scores > -1, and L1-L4 and L2-L4 T-scores > -1)
- Being a volunteer
Key exclusion criteria (8 listed)
- Receiving osteoporosis treatment
- Having a peripheral or central nervous system disorder (e.g., stroke, polyneuropathy, radiculopathy, entrapment neuropathy, etc.)
- Having acquired or hereditary muscle diseases (myopathies)
- Having active painful lower extremity pathologies (e.g., osteoarthritis, inflammatory joint diseases, etc.)
- Having cardiac arrhythmias
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 |
|---|---|---|
| H-reflexAlso: Hoffmann's reflexH-reflex will be measured during 5 different mechanical loads and whole body vibration. | Diagnostic test | Healthy control, Postmenapausal femoral osteoporosis |
| Bone myoregulation reflexBone myoregulation reflex will be measured by applying 10 seconds whole body vibration of 4 different frequencies. | Diagnostic test | Healthy control, Postmenapausal femoral osteoporosis |
Primary outcome
H-reflex Amplitude
Time frame: During the day of testing
H reflex will be measured 10 times each in 5 different mechanical loads and during 1 minute whole-body vibration. Average amplitude of 10 measurements will be calculated.
1 secondary outcome
Bone myoregulation reflex latency
Time frame: During the day of testing
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 28 Nov 2025.
- Individual participant dataSharing planned: Yes. All collected data will be shared
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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.
İlhan Karacan, Prof. Dr. study chair
stanbul Physical Medicine Rehabilitation Training and Research Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing H-reflex and Bone myoregulation reflex in people with Osteoporosis Postmenopausal, 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 4 inclusion and 8 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: looking for participants now, as of the sponsor's last update on 28 Nov 2025. 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?
Contact Fuat Orhun Alayoğlu, Attending doctor (+905348431984, f.orhunalayoglu@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
H-reflex Amplitude (time frame: During the day of testing). 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 28 Nov 2025.