Objective: To assess the effects of pedaling exercise on the muscle activities in hemiparetic lower limbs in patients with stroke.
Design: In this before-and-after trial, 17 nonambulatory patients with chronic hemiparetic stroke were recruited. Using a servo-dynamically controlled ergometer with a trunk support, the patients pedaled at a resistance of 5 N-m at their comfortable speeds. Muscle activities were recorded with surface electrodes from bilateral quadriceps femoris, medial hamstrings, tibialis anterior, and medial gastrocnemius, and integrated electromyograms were used for analysis of muscle activity patterns during the pedaling cycle. Muscle activities during pedaling were compared with those during voluntary knee extension of the affected limb before, immediately after, and 30 min after the pedaling.
Results: We found phasic muscle activities in the affected limb during pedaling that were antiphasic to the contralateral side. The muscle activities of quadriceps femoris and tibialis anterior increased significantly during pedaling compared with those during voluntary knee extension effort, whereas the muscle activity of medial hamstrings did not change. The postpedaling facilitation of quadriceps and tibialis anterior and the inhibition of gastrocnemius during voluntary knee extension effort lasted at least for 30 min.
Conclusion: Pedaling could facilitate phasic and coordinated muscle activities even in patients with severe hemiparesis, and it is potentially an effective mode of muscle reeducation.