The effect of arm movements on the lower limb during gait after a stroke.

The purpose of this study was to examine the influence of arm movements on lower limb movement and muscle activation during treadmill walking after a stroke. Ten high functioning stroke and 10 healthy subjects walked on a treadmill while swinging their arms naturally, and while holding onto handles that were either fixed in place or allowed to slide along horizontal handrails. Full-body kinematics were recorded, along with bilateral surface electromyography from lower limb muscles. Arm movements influenced lower limb muscle activity but had little effect on movement patterns at the joints. When handrails were present a small amount of weight was borne through the upper limbs, and for stroke subjects this was reduced when the handles were free to slide. Activity of proximal leg muscles during stance was affected by the weight borne through the upper limbs, increasing when arm movements were performed. Soleus activity during stance was greatest with unsupported arm movements. In stroke subjects, early stance tibialis anterior activity in the paretic leg was greatest with no arm movements, and early swing tibialis anterior activity in both legs was greatest with unsupported arm movements. Many of the changes in muscle activation appeared to be due to changes in postural stability that occurred when performing arm movements. Overall, results support further study of the long-term changes associated with the inclusion of arm movements in gait rehabilitation protocols. Copyright 2009 Elsevier B.V. All rights reserved.