Effect of Mechanical Loading and Bone Loss on Motor Neuron Activity-H-Reflex Relationship
Recruiting · NCT07253493 · Interventional (participants receive a specific treatment) · Lead sponsor: Istanbul Physical Medicine Rehabilitation Training and Research Hospital
View the official record on ClinicalTrials.gov →Interventions studied
What this trial is about
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.
Who can take part
Inclusion criteria
- 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
Exclusion criteria
- 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
Where it is running
1 location listed.
- Istanbul Physical Medicine Rehabilitation Training & Research Hospital - Bahçelievler, Istanbul, Turkey (Türkiye)