Fig. 2.

Acceleration signals recorded on chest and L5 for children with various gait patterns: a) TD child with normal gait, b) child with CP-GMFCS III, true equinus and recurvatum knees; c) child with CP-GMFCS III, apparent equinus (right side)/crouch (left side) with stiff knees; d) child with CP-GMFCS III, crouch gait. For each subject, the top panel illustrates the raw acceleration along the three axes, i.e., vertical (accV), anteroposterior (accAP) and mediolateral (accML). The middle panel shows the raw acceleration norm (accN, magenta color), after detrending and LPF (accN-LPF, black color), and after continuous wavelet transform (accN-LPF-CWT, red color); steps are identified as the maxima corresponding to heel-strike events (black squares). The bottom panel shows the pitch angular velocity signals recorded on shanks; the reference steps (ground truth) were identified as the maxima corresponding to the mid swing temporal events (blue circles)