The investigation on sEMG of lower extremity when a slip occurs in level walking

The purpose of the present study was to determine the relationship between the surface electromyography (sEMG) variables and slip events using principal component analysis (PCA). Ten healthy young adults were required to walk on the oily surface on a self-selected comfortable pace. The sEMG signals of lower extremity muscles were recorded and analyzed, while kinematics data was recorded to assist slip definitions. When ten variables (seven in time domain and three in frequency domain) were considered in the PCA, the results indicated that 1) three most important principal components could explain more than 85% of the variation in the entire data set; 2) some variables should be especially noticed such as muscle power, the mean frequency, the median frequency and the amplitude amount exceeding the mean value.