Lower leg electromyography activation during gait initiation in multiple sclerosis patients

The present study was designed to evaluate the pattern of lower limb muscle activity during the gait initiation in patients with multiple sclerosis (MS) compared with healthy individuals.

16 female MS patients and 16 age, weight, high and sex-matched healthy subjects were selected by simple non-random sampling participants. Subjects also underwent a thorough neurological examination to assess their disability using the Expanded Disability Status Scale (EDSS≤4.5). Surface electromyography of tibialis anterior, soleus, biceps femoris, gluteus medius, rectus femoris were recorded during gait initiation. The activity of muscles including recruitment order, reaction time, and root mean square (RMS) were processed and compared in two groups.

In the patients group muscles had a significant delay (P<0.02) compared to healthy group. Examination of the RMS ratio of each muscle to the total muscles in the two groups showed that the soleus and gluteus medius muscles were significantly different between the two groups (P<0.05).

Surface electromyography activity showed that the recruitment order was the same in the healthy and multiple sclerosis patients. However, decreasing the share of soleus and gluteus medius muscle co-contraction relative to other selected lower limb muscles in the patients may be useful in examining muscle synergies at the gait initiation in future studies.