In this paper, measurements were acquired from a group of seven subjects with healthy right hips and left hips affected by an osteoarthritic (OA) process in first stage of evolution. The measurements consist in 126 time-series, where values represent the angles of the hip joint in sagittal plane, describing the flexion-extension movement of each hip joint, of each subject performing nine experimental tests of walking on treadmill, at three predefined speeds and three predefined incline angles. Using the experimental time-series, a measure of the local dynamic stability was estimated with Lyapunov exponents.

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