Exercise-mediated locomotor recovery and lower-limb neuroplasticity after stroke.

Assumptions that motor recovery plateaus within months after stroke are being challenged by advances in novel motor-learning-based rehabilitation therapies. The use of lower-limb treadmill (TM) exercise has been effective in improving hemiparetic gait function. In this review, we provide a rationale for treadmill exercise as stimulus for locomotor relearning after stroke. Recent studies using neuroimaging and neurophysiological measures demonstrate central nervous system (CNS) influences on lower-limb motor control and gait. As with studies of upper limbs, evidence shows that rapid transient CNS plasticity can be elicited in the lower limb. Such effects observed after short-term paretic leg exercises suggest potential mechanisms for motor learning with TM exercise. Initial intervention studies provide evidence that long-term TM exercise can mediate CNS plasticity, which is associated with improved gait function. Critical needs are to determine the optimal timing and intensities of TM therapy to maximize plasticity and learning effects.