Concurrent Training vs Soleus Push-Ups on Neurogenesis-Related Biomarkers in Diabetic Neuropathy Patients

Serum Brain-Derived Neurotrophic Factor (BDNF) concentration will be measured quantitatively using a commercially available enzyme-linked immunosorbent assay (ELISA) kit at baseline, 4 weeks, and 8 weeks. BDNF is a neurotrophic factor involved in neuronal survival, synaptic plasticity, and exercise-induced neuroplasticity. Changes in circulating BDNF levels will be used as a primary biomarker of exercise-induced neuroplasticity and neurogenesis-related biological activity. Higher serum BDNF concentrations are considered indicative of greater neurotrophic activity and potential enhancement of neuroplastic processes.

Serum Nerve Growth Factor (NGF) concentration will be measured quantitatively using a commercially available enzyme-linked immunosorbent assay (ELISA) kit at baseline, 4 weeks, and 8 weeks. NGF is a key neurotrophic factor involved in the survival, maintenance, and regeneration of peripheral neurons. It plays a fundamental role in peripheral nerve repair and axonal regeneration following nerve injury. Changes in circulating NGF levels will be used as a primary biomarker of peripheral nerve regeneration and neuroregeneration-related biological activity. Higher serum NGF concentrations are considered indicative of enhanced neurotrophic support and regenerative potential of peripheral nerves.

Serum S100 Calcium-Binding Protein B (S100B) concentration will be measured quantitatively using a commercially available enzyme-linked immunosorbent assay (ELISA) kit at baseline, 4 weeks, and 8 weeks. S100B is a calcium-binding protein that is expressed by Schwann cells in the peripheral nervous system and plays an important role in peripheral nerve repair, remyelination, and axonal regeneration. Changes in circulating S100B levels will be used as a primary biomarker of Schwann cell activity and peripheral nerve regeneration. Higher serum S100B concentrations are considered indicative of increased Schwann cell-mediated neuroregenerative activity.

Neuropathy severity will be assessed using the Michigan Neuropathy Screening Instrument (MNSI), a validated instrument for screening and evaluating diabetic peripheral neuropathy. The MNSI consists of two components: (1) a 15-item patient-reported symptom questionnaire (History; Part A) and (2) a standardized physical examination (Part B) that assesses foot appearance, ulceration, ankle reflexes, and vibration sensation. Assessments will be performed at baseline, 4 weeks, and 8 weeks.

The MNSI History score ranges from 0 to 13, with a score of ≥4 indicating the presence of diabetic peripheral neuropathy. The MNSI Examination score ranges from 0 to 8, with a score of ≥2 considered diagnostic of diabetic peripheral neuropathy. Higher scores on both components indicate greater neuropathy severity, whereas lower scores following the intervention indicate improvement in peripheral nerve function and neuropathic symptoms.

Vibration perception threshold will be assessed using a digital biothesiometer to evaluate large-fiber peripheral nerve function in participants with diabetic peripheral neuropathy. The biothesiometer measures the minimum vibration intensity perceived by the participant and is recorded in volts (V). Assessments will be performed at baseline, 4 weeks, and 8 weeks.

The VPT score ranges from 0 to 50 volts, with higher values indicating poorer vibration perception and more severe peripheral nerve dysfunction. A VPT value of ≥25 volts will be used as the diagnostic threshold for diabetic peripheral neuropathy. A reduction in VPT values following the intervention indicates improved sensory nerve function and reduced neuropathy severity.

Balance and gait performance will be assessed using the validated Balance and Gait mobile application. The application utilizes the smartphone's built-in inertial sensors (accelerometer and gyroscope) to objectively evaluate postural stability and gait performance. Assessments will be conducted at baseline, 4 weeks, and 8 weeks.

The application provides quantitative measures of balance and gait, including postural sway, gait stability, walking speed, cadence, stride characteristics, and an overall balance/gait performance score, depending on the application outputs. Higher balance and gait scores (or improved gait parameters, such as increased gait speed and reduced postural sway) indicate better functional mobility and postural stability, whereas poorer scores indicate greater balance impairment and increased risk of falls.

Glycated hemoglobin (HbA1c) will be measured using a standardized laboratory assay to assess long-term glycemic control. HbA1c reflects the average blood glucose concentration over the preceding 2-3 months and is reported as a percentage (%) of total hemoglobin. Assessments will be performed at baseline, 4 weeks, and 8 weeks.

HbA1c values range from approximately 4% to 14% or higher, with lower values indicating better glycemic control. In accordance with the American Diabetes Association (ADA) criteria, an HbA1c level of <5.7% is considered normal, 5.7%-6.4% indicates prediabetes, and ≥6.5% is diagnostic of diabetes mellitus. Participants eligible for this study will have baseline HbA1c values between 6.5% and 9.0%. A reduction in HbA1c following the intervention will indicate improved long-term glycemic control.

Health-related quality of life will be assessed using the Norfolk Quality of Life-Diabetic Neuropathy (Norfolk QOL-DN) questionnaire, a validated patient-reported outcome measure specifically designed to evaluate the impact of diabetic peripheral neuropathy on physical functioning and quality of life. The questionnaire assesses symptoms and functional limitations across multiple domains, including physical functioning/large-fiber neuropathy, activities of daily living, symptoms, small-fiber neuropathy, and autonomic neuropathy. Assessments will be conducted at baseline, 4 weeks, and 8 weeks.

The Norfolk QOL-DN total score ranges from -4 to 136, with higher scores indicating poorer health-related quality of life and greater neuropathy-related impairment, whereas lower scores indicate better quality of life and reduced symptom burden. A decrease in the total score following the intervention will be interprete

Acceptability of the exercise intervention will be assessed using the Acceptability of Intervention Measure (AIM), a validated implementation outcome instrument. The AIM consists of 4 items rated on a 5-point Likert scale ranging from 1 (Completely Disagree) to 5 (Completely Agree), yielding a total score of 4-20. Higher scores indicate greater participant-perceived acceptability of the intervention. The AIM will be administered at the completion of the 8-week intervention.

Perceived appropriateness of the exercise intervention will be assessed using the Intervention Appropriateness Measure (IAM). The IAM consists of 4 items rated on a 5-point Likert scale ranging from 1 (Completely Disagree) to 5 (Completely Agree), resulting in a total score of 4-20. Higher scores indicate that participants perceive the intervention to be more appropriate and suitable for managing diabetic peripheral neuropathy. The IAM will be administered at the completion of the 8-week intervention.

Feasibility of the exercise intervention will be evaluated using the Feasibility of Intervention Measure (FIM). The FIM consists of 4 items rated on a 5-point Likert scale ranging from 1 (Completely Disagree) to 5 (Completely Agree), yielding a total score of 4-20. Higher scores indicate greater perceived feasibility of implementing the intervention in clinical practice. The FIM will be administered at the completion of the 8-week intervention.