Normalized EMG Amplitude During Repeated Sit-to-Stand Transfers in Patients with Diabetic Peripheral Neuropathy

Diabetic peripheral neuropathy (DPN) causes progressive sensorimotor dysfunction of the lower extremities, impairing mobility and increasing fall risk. Phase-specific neuromuscular activation during repeated sit-to-stand (STS) transfers in DPN remains poorly characterized. This study compared lower-limb muscle activation during repeated STS transfers in fifteen ambulatory DPN patients and fifteen age- and gender-matched healthy controls. Bilateral surface electromyography (sEMG) was recorded from the vastus lateralis, vastus medialis, biceps femoris, gluteus maximus, and gluteus medius; normalized to maximum voluntary contractions (MVCs), and analyzed separately for STS and stand-to-sit phases. No significant between-group differences were observed for any muscle during either phase (all p > 0.05). Effect sizes were small-to-medium, with confidence intervals indicating uncertainty around the estimated between-group differences. Notably, gluteus maximus activation during STS demonstrated the largest between-group effect size, favoring the DPN group (d = 0.54), although this difference was not statistically significant. This finding may indicate a possible proximal hip-extensor strategy that requires confirmation in larger studies. Both groups demonstrated significantly greater vastus lateralis and gluteus maximus activation during STS than stand-to-sit, reflecting greater neuromuscular demand during rising. Overall, the non-significant between-group findings, together with the effect-size and confidence-interval analysis, suggest that MVC-normalized EMG amplitude alone may have limited sensitivity for detecting neuropathic neuromuscular alterations during transitional tasks in ambulatory patients with DPN.