Effects of treadmill exercise on transcranial magnetic stimulation-induced excitability to quadriceps after stroke.

Abstract

To determine characteristics of transcranial magnetic stimulation (TMS)-induced measures of central motor excitability to the paretic and nonparetic quadriceps muscles of chronic hemiparetic stroke patients in the context of a short-term, submaximal bout treadmill exercise. Cross-sectional. Motor control and gait biomechanics laboratory. Convenience sample of 11 patients including cohorts of treadmill untrained (n=8) and trained (n=3) stroke patients with chronic hemiparetic gait. Short-term submaximal treadmill exercise. Thresholds, amplitudes and latencies of TMS-induced motor evoked potentials at vastus medialis in paretic and nonparetic lower extremities. Baseline characteristics of the motor evoked potentials (MEPs) show significantly higher motor thresholds, longer latencies, and reduced amplitudes on the paretic side. In cross-sectional comparisons a group of treadmill-trained patients had greater paretic MEP amplitude changes after treadmill exercise versus paretic MEP responses from a group of untrained patients. These results indicate that treadmill training for 3 months or more may alter responsiveness of the lower-extremity central motor pathways to a short-term treadmill stimulus.