Parkinson's disease (PD) is one of the most common neurodegenerative disorders. The parkinsonian gait is characterized by reducted stride length and gait speed, postural disorders (with a high risk of falling) and a modification of stride duration variability. This variability can be assessed by its magnitude (SD and CV) and its temporal organization (long-range autocorrelations). Healthy human gait presents with an interdependency between consecutive cycles that can span over hundreds of strides (long-range autocorrelations). Numerous observations plead for a relation between long-range autocorrelations and functional abilities of the system. Complementary to drugs, rehabilitation becomes an important way to treat PD.