This observational study aims to investigate the relationship between vitamin D deficiency, postural stability, and neuromuscular control mechanisms in adults. The study will compare individuals with vitamin D deficiency and healthy controls.
Participants will undergo a single-session evaluation including surface electromyography and postural stability assessments during standing tasks under different loading and vibration conditions. No invasive procedures, medications, or blood sampling will be performed. Previously obtained routine laboratory results will be used for vitamin D status.
The study is designed to improve understanding of neuromuscular responses associated with vitamin D deficiency and to contribute to future rehabilitation strategies.
Age 20 to 40 years.
Ability to provide written informed consent.
Vitamin D deficiency group: serum 25-hydroxyvitamin D level <10 ng/mL measured within the last 3 months (routine clinical testing).
Healthy control group: normal vitamin D status based on routine clinical testing within the last 3 months.
Known metabolic bone disease other than vitamin D deficiency.
Neurological disorder (central or peripheral) or neuromuscular disease.
History of lower-limb surgery, fracture, or prosthesis affecting standing balance.
Vestibular disorder.