Examples from stroke subjects. Joint angles (± SD band) of four representative stroke subjects during hand opening (left panels) and corresponding snapshots of hand postures at maximum aperture (right panels). Grey bands represent healthy control range (± SD). To facilitate comparisons, angles are represented as a percentage of the range between the resting angle of the patient (0%) and the mean maximum extension angles of healthy subjects (100%). Type I hand (a) showed reduced extension of MCPJ and normal extension of IPJ. Type II hand (b) revealed reduced extension of IPJ and normal extension of MCPJ. Type III hand (c) showed reduced extension of both MCPJ and IPJ. Note that the subject's attempt to extend index IPJ (thin dashed line) resulted in an undesired flexion. Type MIX subject (d) showed different behaviour among long fingers. In particular, finger 2 to 4 revealed normal extension of both MCPJ and IPJ (type 0 fingers), while finger 5 (thin line) showed impairment of MCPJ only (type I finger).