A bilateral evaluation of the trapezius muscle was carried out, clinically and by surface electromyography, in 11 stroke patients, in order to compare the activation amplitude of the upper trapezius muscle in different movements of upper limb, using the healthy side as comparison parameter. At our request of analytical activation of the trapezius (consisting in raising their shoulders), we noted in all of them a contraction, both clinically and by EMG valuable. On the contrary at our request of the fixation activity of the shoulder girdle by the trapezius (humeral flexion) we couldn't notice a considerable activation in 4 patients. These data suggest that the trapezius is more active during voluntary movements than in postural fixation, and suggest the use of rehabilitation techniques focusing on the voluntary control.