tokens: Note : TC : time - continuous waveforms for three dimensions ( 3 ) and two steps ( 2 ) ; TD : time - discrete gait variables of minima and maxima of the three dimensions ( GRF : 7 ; Jerk : 6 ) for two steps ( 2 ) and their relative occurrences ( 2 ) ; PCA : Median and interquartile distance of the number of principle components .