Fleisig G S, Andrews J R, Dillman C J, Escamilla R F
Research Research Division, American Sports Medicine Institute, Birmingham, AL 35255-0039, USA.
Am J Sports Med. 1995 Mar-Apr;23(2):233-9. doi: 10.1177/036354659502300218.
Elbow and shoulder kinetics for 26 highly skilled, healthy adult pitchers were calculated using high-speed motion analysis. Two critical instants were 1) shortly before the arm reached maximum external rotation, when 67 N-m of shoulder internal rotation torque and 64 N-m of elbow varus torque were generated, and 2) shortly after ball release, when 1090 N of shoulder compressive force was produced. Inability to generate sufficient elbow varus torque may result in medial tension, lateral compression, or posteromedial impingement injury. At the glenohumeral joint, compressive force, joint laxity, and 380 N of anterior force during arm cocking can lead to anterior glenoid labral tear. Rapid internal rotation in combination with these forces can produce a grinding injury factor on the labrum. After ball release, 400 N of posterior force, 1090 N of compressive force, and 97 N-m of horizontal abduction torque are generated at the shoulder; contribution of rotator cuff muscles in generating these loads may result in cuff tensile failure. Horizontal adduction, internal rotation, and superior translation of the abducted humerus may cause subacromial impingement. Tension in the biceps tendon, due to muscle contraction for both elbow flexion torque and shoulder compressive force, may tear the anterosuperior labrum.
使用高速运动分析计算了26名技术高超、身体健康的成年投手的肘部和肩部动力学。两个关键瞬间分别为：1）手臂达到最大外旋前不久，此时产生67牛米的肩部内旋扭矩和64牛米的肘部内翻扭矩；2）球释放后不久，此时产生1090牛的肩部压缩力。无法产生足够的肘部内翻扭矩可能会导致内侧张力、外侧压缩或后内侧撞击损伤。在盂肱关节处，手臂上举时的压缩力、关节松弛度以及380牛的前向力可能会导致前盂唇撕裂。快速内旋与这些力相结合会在盂唇上产生摩擦损伤因素。球释放后，肩部会产生400牛的后向力、1090牛的压缩力和97牛米的水平外展扭矩；肩袖肌群在产生这些负荷中的作用可能会导致肩袖拉伸失效。外展肱骨的水平内收、内旋和上移可能会导致肩峰下撞击。由于肌肉收缩产生肘部屈曲扭矩和肩部压缩力，肱二头肌腱的张力可能会撕裂前上盂唇。
