H-Reflex Suppression by Bone Myoregulation Reflex During Mechanical Loading in Standing Humans

NCT07043595 | Completed

• 1 other identifier: HReflexBMR2025
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to investigate how standing posture and mechanical loading affect reflex responses in the lower limb. Specifically, it focuses on the H-reflex-a type of spinal cord reflex-and how it changes during quiet standing and whole-body vibration. Ten healthy adult volunteers will participate. Researchers will record electrical responses from the calf muscle (soleus) while participants stand still or are exposed to gentle vibration. The goal is to better understand how the nervous system and skeletal system interact in regulating balance and movement.

Conditions

H-reflex; Spinal Reflexes; Posture; Weight-Bearing; Neuromuscular Physiology

Keywords

Bone Myoregulation Reflex; Whole-Body Vibration; Electrophysiology; Soleus Muscle; Presynaptic Inhibition; Mechanoreceptors; Reflex Suppression

Outcome Measures

Primary Outcomes (1)

• H-reflex Amplitude

  The amplitude of the H-reflex recorded from the soleus muscle, evoked at 15% Mmax stimulation level, will be measured during each condition (quiet standing, one-leg stance, and whole-body vibration). The primary aim is to assess changes in spinal excitability due to mechanical loading.

  Day 1 (single-session, during each experimental condition)

Secondary Outcomes (1)

• Background EMG Activity

  Day 1 (450 ms window prior to stimulation)

Study Arms (1)

Postural Loading and Vibration Arm

EXPERIMENTAL

Participants in this arm will undergo a sequence of experimental conditions involving postural and mechanical loading. The protocol includes standing quietly on both feet, standing on one foot (right or left), and standing during whole-body vibration (WBV). H-reflex recordings will be obtained from the soleus muscle during each condition to assess changes in spinal reflex excitability.

Procedure: Whole-Body Vibration (WBV)

Interventions

Whole-Body Vibration (WBV) PROCEDURE

Participants will stand quietly in an upright position while whole-body vibration (WBV) is applied through a vibration platform. The vibration stimulus is delivered while the participant's left foot remains on the vibration surface and the right foot is elevated or isolated. H-reflex recordings are taken from the soleus muscle during the procedure to assess spinal reflex modulation due to mechanical loading.

Also known as: WBV

Postural Loading and Vibration Arm

Eligibility Criteria

• Age: 20 Years - 45 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy adults aged 20 to 45 years
• Able to stand independently for at least 10 minutes
• No known neurological, orthopedic, or balance disorders
• Willingness to participate and provide informed consent

You may not qualify if:

• History of spinal cord injury, peripheral neuropathy, or muscle disease
• Recent lower limb surgery or musculoskeletal trauma
• Current use of medications affecting neuromuscular function
• Pregnancy
• Any contraindications to exposure to mechanical vibration

Sponsors & Collaborators

• Istanbul Physical Medicine Rehabilitation Training and Research Hospital: lead

Study Sites (1)

Istanbul Physical Medicine and Rehabilitation Training and Research Hospital

Istanbul, Istanbul, Turkey (Türkiye)

Location

Study Officials

• Selim Sezikli, MD

  Istanbul Physical Medicine and Rehabilitation Training and Research Hospital

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Specialist in Physical Medicine and Rehabilitation

Model Details: Single-group crossover design in which each participant undergoes all experimental conditions in a fixed order, including quiet standing, weight-shifting, and whole-body vibration. Electrophysiological recordings are obtained during each condition.

Study Record Dates

• First Submitted: June 22, 2025
• First Posted: June 29, 2025
• Study Start: June 24, 2025
• Primary Completion: July 7, 2025
• Study Completion: July 10, 2025
• Last Updated: September 4, 2025

Record last verified: 2025-08

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)