Fig. 2

The extracted features. This figure illustrates the features extracted from different gait variables. (A) Hip trajectory; (F1) hip maximum extension, and (F2) hip range of motion. (B) Knee trajectory; (F3) knee maximum flexion, and (F4) knee range of motion. (C) Gait path; (F5) area of gait path. (D) Hip velocity; (F6) hip maximum angular velocity, and (F7) hip minimum angular velocity. (E) Knee velocity; (F8) knee maximum angular velocity, and (F9) knee minimum angular velocity. (F) Path speed; (F10) area of path speed. (G) Hip limit cycle; (F11) area of hip limit cycle. (H) knee limit cycle; (F12) area of knee limit cycle during swing (the greater closed curve), and (F13) area of knee limit cycle during stance (the smaller closed curve). (I) Gait speed is computed as Frobenius norm of hip and knee angular velocities, which is a function of gait cycle; (F14) area under gait speed during mid-swing. In all graphs, the zero gait cycle is considered at the heel strike instant.