The abnormal co-activation of antagonists and proximal muscles should increase under double motor task conditions, where the patient will be asked to perform symmetrical or different movements simultaneously with the two limbs. Based on the hypothesis that symmetrical coupling of motor effectors is easier to control than asymmetrical patterns, which require inter-hemispheric inhibition of the irrelevant movement, motor performance should be more difficult and diffusion of the motor command should be increased in the asymmetrical motor tasks.