Dendrogram representing the minimum variance hierarchical classification of the gait patterns of healthy young and elderly men. Four groups (families) are labeled Y1 for the young-men's family, and El to E3 for the 3 elderly-men families. The figure is read from the bottom, where the individual trials are listed, in 4 families, to top, where all the gait trials are grouped into a single family. Reproduced with permission (Watelain et al., 2000).