This theses explores muscle activity during bow draw. The goal of his study is to evaluate whether muscle activity corresponds with increase in mechanical robusticity of the left humerus found in mezolithic osteological material. Muscle activity is measured by the means of surface electromyography. We measure activity of arm and back muscles. Activity was measured on m. deltoideus, m. infraspinatus, m. biceps brachii, m. triceps brachii and m. latissimus dorsi. Muscle activity was measured on 20 male archers, during bow draw of three wooden long-bows. Results of this study support the idea that change in robusticity of the left humerus could be caused by frequent bow use in post-glacial Europe.