Effects of low vs. high frequency local vibration on mild-moderate muscle spasticity: Ultrasonographical and functional evaluation in patients with multiple sclerosis

•Only 50 Hz LV appears to be effective in increasing fascicle length.•LV appears to have no substantial effect on spasticity.•LV has positive effects on ML limits of stability. Local vibration (LV) is a physiotherapy application that aims to reduce spasticity. The study aimed to compare the effects of 50 Hz vs. 100 Hz LV on mild-moderate spasticity, functional performance and muscle architecture. Thirty-three patients were randomly divided into three groups: 50 Hz LV group, 100 Hz LV group and the control group. Physical therapy was applied for one hour a day, three days a week, for a total of eight weeks. LV was applied to the right and left medial gastrocnemius muscles for five minutes. Clinical (spasticity, ankle joint position sense, balance, gait) and ultrasonographic (gastrocnemius fascicle length and pennation angle) measurements were performed before and after treatment. The study was completed with 27 patients. The decrease in spasticity and the increase in fascicle length were found to be statistically significant in the 50 Hz group (both p