The study team is recruiting 25 adults with spasticity due to chronic stroke for a 4 day study. In people with chronic stroke, one of the most common and disabling problems is spasticity (increased muscle tone or muscle stiffness). The purpose of this research study is to examine effects of dry needling on the nervous system (pathways between the muscle, spinal cord, and brain) in people with spasticity due to chronic stroke. Dry needling is a procedure in which a thin, stainless steel needle is inserted into the skin to produce a muscle twitch response. It is intended to release a knot in a person's muscle and relieve pain.

The total study duration is 3 visits over 4 days. The first visit will last about 3 hours, and the second and third visits will last about 1.5 hours. Dry needling will take place on the first visit only. During each visit the participant will be asked to participate in examinations of reflexes (muscle responses to non-invasive nerve stimulation) and leg function.