A spherical model analyzing shoulder motion in overhand and sidearm pitching.

Abstract

An accurate measurement of shoulder movement in pitching is indispensable in clarifying the causes of shoulder problems stemming from baseball pitching and in preventing these disorders. In this investigation, three-dimensional imaging and electromyography were performed during pitching. Two different pitching methods (overhand throwing and sidearm throwing) of 35 amateur pitchers were analyzed with a high-speed video imaging system. In 25 subjects shoulder rotation during pitching was measured with a compact camera attached to the shoulder. In 21 subjects, the electromyographic activity of the biceps and triceps muscles during pitching was examined. Image analysis showed little difference in shoulder movement between the two pitching methods for each subject, while individual subjects had specific shoulder movements. Electromyography demonstrated the role of the triceps muscle during pitching. The clinical ramifications of these analyses may be very useful.