Bone Myoregulation Reflex in Senile Osteoporosis

Is the Bone Myoregulation Reflex Response to Weight-Bearing Activities Low in Senile Osteoporosis?

Osteoporosis is a systemic skeletal disease characterized by weakened and fragile bones. It often remains asymptomatic in its early stages but can lead to serious health problems, particularly fractures.The mechanostat theory explains that bone mass is regulated by mechanical loading. Increased activity stimulates bone formation, while decreased activity promotes bone resorption. The "bone reflex" concept further suggests that the nervous system plays a crucial role in this process by regulating both bone metabolism (osteoregulation) and muscle activity (myoregulation) in response to mechanical loading.

Background and Objectives:Osteoporosis is a systemic skeletal disease characterized by weakened and fragile bone tissue. Typically asymptomatic in its early stages, it can lead to severe health consequences, particularly fractures. Bone mineral density (BMD) measurements, as defined by the World Health Organization, are considered the gold standard for diagnosing osteoporosis. The prevalence of osteoporosis is on the rise due to the aging population and the influence of lifestyle factors.

Recently, the bone reflex has been defined, suggesting that the central nervous system controls the local regulatory mechanisms described by Wolf and Frost. The bone reflex describes how osteocytes are stimulated by mechanical loading, leading to the neural regulation of bone formation and resorption according to mechanical needs (bone osteoregulation reflex). Additionally, it describes a mechanism by which the nervous system reflexively regulates the activity of surrounding muscles to optimally position the bone to resist applied mechanical load (bone myoregulation reflex).

Methods: This study employs a quasi-experimental design. The study will be conducted with a total of 22 patients aged 60-70, men. Diagnosis of osteoporosis was made according to the World Health Organization classification. Individuals with a T-score of -2.5 or below were classified as having osteoporosis. Participants will be divided into two groups: a group with osteoporosis (Group 1) and a group without osteoporosis (Group 2).

Procedures:

Bone myoregulation reflex activity of the soleus and tibialis anterior muscles will be assessed in both groups during whole-body vibration and jumping using surface electromyography.

• Jumping Test: Participants will be instructed to jump in place 20 times, similar to rope skipping, with a 5-second rest interval between each jump.
• Whole-Body Vibration: Participants will stand on the plate and undergo low-amplitude (1.2 mm) whole-body vibration at eight different frequencies (25, 27, 29, 31, 33, 35, 37, and 39 Hz) using a Powerplate Pro5 (Netherlands) device. Each vibration session will last for 10 seconds, with a 5-second rest interval between frequencies.
• The Achilles tendon will be percussed 10 times with an electronic reflex hammer.

Inclusion Criteria:

• DXA T-scores ≤-2.5 (osteoporotic) or T-scores > -1 (no bone loss)
• Individuals who agree to participate in the study

Exclusion Criteria:

• History of musculoskeletal surgery within the past year
• Individuals with health conditions that severely affect mobility
• Vestibular disorders
• Visual impairments
• Other rheumatic, psychiatric, or severe neurological diseases
• Chronic decompensated cardiac, renal, or hepatic insufficiency
• Panic attacks
• Individuals with skin lesions on the soleus muscle
• History of fractures or prostheses in the lower extremities
• History of kidney stones
• 2+ or more edema in the lower extremities, lymphedema
• History of malignancy
• History of osteomalacia or vitamin D deficiency