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

NCT ID: NCT07043595

Last Updated: 2025-09-04

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 10 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-06-24
• Study Completion Date: 2025-07-10

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.

Detailed Description

This study investigates the neural mechanisms responsible for suppression of the H-reflex-a spinal monosynaptic reflex-during mechanical loading in the standing position. Previous research has shown that H-reflex amplitude decreases with increasing postural demand, such as during walking or standing compared to lying down. One hypothesis suggests that this suppression may be mediated not only by vestibular and cutaneous afferents, but also by a bone-derived reflex mechanism called the Bone Myoregulation Reflex (BMR).

In this study, 10 healthy adult volunteers will undergo H-reflex measurements while standing in various loading conditions, including quiet standing and during whole-body vibration (WBV). Participants will stand with one foot isolated from vibration while the other foot is on a vibrating platform. H-reflexes will be recorded from the soleus muscle using standard surface electromyography.

The primary aim is to determine whether BMR contributes to H-reflex suppression during loading. The findings may provide insight into the interaction between skeletal loading and spinal reflex modulation, with potential relevance to balance, gait, and rehabilitation science.

Conditions

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

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Postural Loading and Vibration Arm

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.

Group Type: EXPERIMENTAL

Whole-Body Vibration (WBV)

Intervention Type: 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.

Interventions

Whole-Body Vibration (WBV)

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.

Intervention Type: PROCEDURE

Other Intervention Names

WBV

Eligibility Criteria

Inclusion Criteria

• 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

Exclusion Criteria

• 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

• Minimum Eligible Age: 20 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Istanbul Physical Medicine Rehabilitation Training and Research Hospital

OTHER_GOV

Sponsor Role: lead

Responsible Party

Selim Sezikli

Specialist in Physical Medicine and Rehabilitation

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Selim Sezikli, MD

Role: PRINCIPAL_INVESTIGATOR

Istanbul Physical Medicine and Rehabilitation Training and Research Hospital

Locations

Istanbul Physical Medicine and Rehabilitation Training and Research Hospital

Istanbul, Istanbul, Turkey (Türkiye)

Countries

Turkey (Türkiye)

Other Identifiers

HReflexBMR2025

Identifier Type: -

Identifier Source: org_study_id