Abstract: Objective To analyze the features of surface electromyography (sEMG) signal of the tibial anterior muscle and gastrocnemius muscle in the stroke patients when sitting and standing.Methods Fifteen stroke patients and fifteen normal subjects were involved in this study. All subjects were asked to stand up and sit down. It repeated five times continuously. The electromyographic signals were collected by surface electrode and then processed by linear time and frequency domain method.Results In sitting position, tibial anterior muscle had significant differences in mean power frequency and median frequency ( P<0.05) when the paretic and non-paretic lower limb, the non-paretic lower limb in stroke patients and in normal subjects were compared. The gastrocnemius muscle had notable differences ( P<0.05) in root mean square when the non-paretic lower limb in stroke patients and in normal subjects were compared. In standing position, tibial anterior muscle also had significant differences in root mean square and integrated electromyography ( P<0.05) as the same frequency domain comparing as above. The gastrocnemius muscle had notable differences on time domain, when the paretic and non-paretic lower limb, the paretic lower limb in stroke patients and the limb in normal subjects were compared ( P<0.05 or P<0.01).Conclusion sEMG is a brief, applied, feasible assessment method in rehabilitation.

Key words: stroke, tibial anterior muscle, gastrocnemius muscle, surface electromyography (sEMG)