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Background and Objective: Multiple sclerosis (MS) is one of the most common diseases of the central nervous system. MS is more common among women. Gait pattern dysfunction is a relevant symptom in these patients. This study was conducted to compare the electromyography activity of selected lower extremity muscles and the ellipse area of center of pressure during unplanned gait termination in female patients with multiple sclerosis and healthy individuals.
Methods: This case-control study was performed on 10 female patients with MS (classified based on the EDSS scale) and 10 healthy subjects matched for height, age and weight. Electromyography activity of rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), semitendinosus (SM), gastrocnemius medius (GM) and tibialis anterior (TA) and center of pressure (CoP) recorded using foot pressure system during unplanned gait termination. Subjects were instructed to stop, as soon as possible, in response to an auditory cue delivered when the heel strike phase accidentally.
Results: Vastus Lateralis muscle activity was significantly higher in able-bodied group than patients (P<0.05), whereas in the patient group gastrocnemius medius muscle activity increased significantly (P<0.05). Also, the ellipse area of center of pressure significantly reduced in MS group in compered to able-bodied group (P<0.05).
Conclusion: Increased gastrocnemius medius muscle activity in MS patients may be due to their attempt to slow down the displacement of the center of mass to limit the tibia forward translation consequently, attempting to control balance as a strategy to limit the ellipse area of center of pressure to prevent fall.