Does Treadmill Exercise Improve Performance of Cognitive or Upper-Extremity Tasks in People With Chronic Stroke? A Randomized Cross-Over Trial

Objective: To determine whether acute exercise, using a body-weight-supported treadmill, improves performance on subsequent cognitive tests or an upper-extremity task in people with stroke. Design: The study was a within-subject, cross-over design in which 21 subjects received, randomly, 2 different testing sequences separated by an interval of 7 to 10 days. Setting: Outpatient department of a rehabilitation hospital. Participants: Of 72 potential participants in the convenience sample, 21 people with chronic stroke completed the study. They were 0.5 to 5 years after only I documented stroke, were able to walk with or without a cane, were able to grasp with the affected hand, and scored more than 24 on the Mini-Mental State Examination. Interventions: One session of body-weight-supported treadmill walking for 20 minutes at 70% of estimated heart rate reserve or level 13 on the Borg rating of perceived exertion scale. The control condition consisted of a 20-minute review of a home exercise program with a physiotherapist. Main Outcome Measures: Cognitive tests included Trail Making Tests Parts A and B, Symbol Digit Substitution Test, and Paced Auditory Serial Addition Test. The Action Research Arm Test (ARAT) measured hemiplegic upper-extremity motor skill. Results: Treadmill exercise improved movement of the hemiplegic upper extremity (P=.04) but not cognitive performance. The improvement in the ARAT occurred without a change in strength (measured by grip strength) and was negatively correlated with maximum treadmill speed (R-2=.20; P=.04). Conclusions: These findings suggest that acute treadmill exercise improves subsequent skilled movement of the hemiplegic upper extremity that seems unrelated to attention, visuo-motor processing, or strength. The etiology and duration of this enhancing effect are worth further study. The existence of an exercise-cognition relationship in people with stroke is an intriguing area of future research.