棒球的投擲動作多採過肩運動，而長時間的訓練以及慣用臂的重複使用往往提高受傷的風險。本研究希望了解投手在單一部位疲勞後投球的機制，並提出有效方案以改善慣用臂使用情況。本研究目的為探討單一部位疲勞流程對投手投擲直球的影響，比較有無肩部傷害史的實驗參與者之間的運動學參數差異和透過動力學數值計算評估受傷風險較高的力量閾值為何。完成肩部疲勞流程後，所有實驗參與者的控球表現與球速均未達顯著差異。同時，上舉期的肩關節最大外旋角度 (P = 0.015)以及加速期時的肩關節最大外展角度則也有顯著差異 (P = 0.004)，疲勞狀態下的肩關節最大內旋角速度也下降 (P = 0.008)。有肩部傷史的投手投擲直球在加速期有著較小的肩關節外展角度以及較慢的內收角速度，肌肉活化程度主要以旋轉肌群的棘下肌的肌肉徵召下降較為顯著 (P = 0.003)，而手肘內翻力矩 (P = 0.060) 也些微影響投擲直球過程。在肩部疲勞狀態下，所有的投手仍能兼顧投擲直球的球速與準確度。投球動作的表現與肌肉活化程度因為肩部疲勞而產生變化，在疲勞狀態下，投手需要以較小的揮臂軌跡與強化旋轉肌群來保護肩部前側肌肉與肩關節盂唇。增加熱身項目及時間和限制比賽及練習中的用球數是避免上肢使用過度而受傷。歷經投球之後完整伸展活動與增加旋轉肌群強度是延長投球生涯的關鍵。

As overhead movement plays a major role in baseball pitching, highly repetitive motion or long-term training or overuse under fatigue is highly related to a risk of dominant shoulder injuries. The purpose of this study was to investigate the mechanism of pitching after fatigue had occurred, identify the effect of fatigue protocol on the local joint and then conducted a comparison in kinematics, kinetics, and electromyography (EMG) data between injury and control groups to determine whether there was the significant difference after the fatigue protocol. The results showed no significant difference in ball speed and accuracy of pitching between the fatigue tests. However, there were significant differences in the maximum shoulder external rotation angle in the cocking phase (P = 0.015), the maximum internal rotation angular velocity in the acceleration phase (P = 0.008), and the smaller shoulder abduction angle in the acceleration phase (P = 0.004) after the fatigue protocol. Infraspinatus of the muscle activity had a significant difference in the EMG result after the fatigue test (P = 0.003). In spite of the fact that there was no significant difference in the kinetic results (P = 0.060), elbow varus torque still affected baseball fastball pitching. To guarantee the maximum performance without sacrificing ball speed and accuracy, pitchers would depend on smaller swinging trajectory and the enhancement of rotator cuff to protect their shoulder anterior muscle and the shoulder joint lip. Increasing the warm-up project and time and limiting the number of balls pitched in the game, and practice were an important way to avoid injury. Complete stretching activities and enhancement of the strength of the rotating muscles after pitching were the key to prolonging the pitching career.

Alizadehkhaiyat, O., Hawkes, D. H., Kemp, G. J., & Frostick, S. P. (2015). Electromyographic analysis of shoulder girdle muscles during common internal rotation exercises. International Journal of Sports Physical Therapy, 10(5), 645.
Andrews. (1984). The Arthroscopic treatment of glenoid labrum tears in the throwing athlete. Eastern orthopaedic Association. Orthopaedic Transactions, 8, 44.
Andrews, Kupferman, & Dillman. (1991). Labral tears in throwing and racquet sports. Clinics In Sports Medicine, 10(4), 901-911.
Bartlett, L. R., Storey, M. D., & Simons, B. D. (1989). Measurement of upper extremity torque production and its relationship to throwing speed in the competitive athlete. The American Journal of Sports Medicine, 17(1), 89-91.
Biedert, R., & Kentsch, A. (1989). Arthroscopic revision of the sub-acromial space in impingement syndrome. Der Unfallchirurg, 92(10), 500-504.
Blackburn, T. (1990). EMG analysis of posterior rotator cuff exercises. Journal of Athlete Train, 25, 40-45.
Blangsted, A. K., Sjøgaard, G., Madeleine, P., Olsen, H. B., & Søgaard, K. (2005). Voluntary low-force contraction elicits prolonged low-frequency fatigue and changes in surface electromyography and mechanomyography. Journal of electromyography and kinesiology, 15(2), 138-148.
Burkhart, Morgan, & Kibler. (2003). The disabled throwing shoulder: spectrum of pathology Part I: pathoanatomy and biomechanics. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 19(4), 404-420.
Chalmers, P. N., Wimmer, M. A., Verma, N. N., Cole, B. J., Romeo, A. A., Cvetanovich, G. L., & Pearl, M. L. (2017). The relationship between pitching mechanics and injury: a review of current concepts. Sports Health, 9(3), 216-221.
Cohen, J. (1992). A power primer. Psychological bulletin, 112(1), 155.
Dillman, C. J., Fleisig, G. S., & Andrews, J. R. (1993). Biomechanics of pitching with emphasis upon shoulder kinematics. Journal of Orthopaedic & Sports Physical Therapy, 18(2), 402-408.
Dinnes, J., Loveman, E., McIntyre, L., & Waugh, N. (2003). The effectiveness of diagnostic tests for the assessment of shoulder pain due to soft tissue disorders: a systematic review. Health Technology Assessment, 7(29), 1-166.
Dockery, M. L., Wright, T. W., & LaStayo, P. C. (1998). Electromyography of the shoulder: an analysis of passive modes of exercise. Orthopedics, 21(11), 1181-1184.
Dun, S., Loftice, J., Fleisig, G. S., Kingsley, D., & Andrews, J. R. (2008). A biomechanical comparison of youth baseball pitches: is the curveball potentially harmful? The American Journal of Sports Medicine, 36(4), 686-692.
Escamilla, R. F., Barrentine, S. W., Fleisig, G. S., Zheng, N., Takada, Y., Kingsley, D., & Andrews, J. R. (2007). Pitching biomechanics as a pitcher approaches muscular fatigue during a simulated baseball game. The American Journal of Sports Medicine, 35(1), 23-33.
Escamilla, R. F., Fleisig, G. S., Barrentine, S. W., Zheng, N., & Andrews, J. R. (1998). Kinematic comparisons of throwing different types of baseball pitches. Journal of Applied Biomechanics, 14(1), 1-23.
Escamilla, R. F., Yamashiro, K., Paulos, L., & Andrews, J. R. (2009). Shoulder muscle activity and function in common shoulder rehabilitation exercises. Sports medicine, 39(8), 663-685.
Feltner, M., & Dapena, J. (1986). Dynamics of the shoulder and elbow joints of the throwing arm during a baseball pitch. Journal of Applied Biomechanics, 2(4), 235-259.
Fitts, P. M. (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47(6), 381.
Fleisig. (1994). Biomechanics of the shoulder during throwing. The Athlete's Shoulder.
Fleisig, Andrews, Dillman, & Escamilla. (1995). Kinetics of baseball pitching with implications about injury mechanisms. The American Journal of Sports Medicine, 23(2), 233-239.
Fleisig, Barrentine, Zheng, Escamilla, & Andrews. (1999). Kinematic and kinetic comparison of baseball pitching among various levels of development. Journal of Biomechanics, 32(12), 1371-1375.
Fleisig, Diffendaffer, Ivey, & Aune. (2018). Do baseball pitchers improve mechanics after biomechanical evaluations? Sports Biomechanics, 17(3), 314-321.
Fleisig, Phillips, Shatley, Loftice, Dun, Drake, . . . Andrews. (2006). Kinematics and kinetics of youth baseball pitching with standard and lightweight balls. Sports Engineering, 9(3), 155.
Fortenbaugh, D., Fleisig, G. S., & Andrews, J. R. (2009). Baseball pitching biomechanics in relation to injury risk and performance. Sports Health, 1(4), 314-320.
Fuller, J. R., Lomond, K. V., Fung, J., & Côté, J. N. (2009). Posture-movement changes following repetitive motion-induced shoulder muscle fatigue. Journal of Electromyography and Kinesiology, 19(6), 1043-1052.
Glousman, R. E., Barron, J., Jobe, F. W., Perry, J., & Pink, M. (1992). An electromyographic analysis of the elbow in normal and injured pitchers with medial collateral ligament insufficiency. The American Journal of Sports Medicine, 20(3), 311-317.
Gowan, I. D., Jobe, F. W., Tibone, J. E., Perry, J., & Moynes, D. R. (1987). A comparative electromyographic analysis of the shoulder during pitching: professional versus amateur pitchers. The American Journal of Sports Medicine, 15(6), 586-590.
Hagberg, M. (1981). Work load and fatigue in repetitive arm elevations. Ergonomics, 24(7), 543-555.
Harryman 2nd, D., Sidles, J., Clark, J. M., McQuade, K. J., Gibb, T. D., & Matsen 3rd, F. (1990). Translation of the humeral head on the glenoid with passive glenohumeral motion. The Journal of Bone and Joint Surgery, 72(9), 1334-1343.
Hislop, H., Avers, D., & Brown, M. (2013). Daniels and Worthingham's Muscle Testing-E-Book: Techniques of Manual Examination and Performance Testing: Elsevier Health Sciences.
Jacobson, R. P., & Benson, C. J. (2001). Amateur volleyball attackers competing despite shoulder pain: analysis of play habits, anthropometric data, and specific pathologies. Physical Therapy in Sport, 2(3), 112-122.
Jerosch, J., Castro, W., & Sons, H. (1990). Secondary impingement syndrome in athletes. Sportverletzung Sportschaden: Organ der Gesellschaft fur Orthopadisch-Traumatologische Sportmedizin, 4(4), 180-185.
Jobe, Giangarra, Kvitne, & Glousman. (1991). Anterior capsulolabral reconstruction of the shoulder in athletes in overhand sports. The American Journal of Sports Medicine, 19(5), 428-434.
Jobe, & Lannotti. (1995). Limits imposed on glenohumeral motion by joint geometry. Journal of Soulder and Elbow Surgery, 4(4), 281-285.
Jobe, Moynes, Tibone, & Perry. (1984). An EMG analysis of the shoulder in pitching: a second report. The American Journal of Sports Medicine, 12(3), 218-220.
Kanematsu, Y., Matsuura, T., Kashiwaguchi, S., Iwase, T., Suzue, N., Iwame, T., . . . Sairyo, K. (2015). Epidemiology of shoulder injuries in young baseball players and grading of radiologic findings of Little Leaguer's shoulder. The Journal of Medical Investigation, 62(3.4), 123-125.
Kibler. (1998). The role of the scapula in athletic shoulder function. The American Journal of Sports Medicine, 26(2), 325-337.
Kibler, Sciascia, Uhl, Tambay, & Cunningham. (2008). Electromyographic analysis of specific exercises for scapular control in early phases of shoulder rehabilitation. The American Journal of Sports Medicine, 36(9), 1789-1798.
Kirkendall, D. T. (1990). Mechanisms of peripheral fatigue. Medicine and Science in Sports and Exercise, 22(4), 444-449.
Kumar, S. (2006). Localized muscle fatigue: review of three experiments. Brazilian Journal of Physical Therapy, 10(1), 9-28.
Limpisvasti, O., ElAttrache, N. S., & Jobe, F. W. (2007). Understanding shoulder and elbow injuries in baseball. Journal of the American Academy of Orthopaedic Surgeons, 15(3), 139-147.
Lo, Y., Hsu, Y., & Chan, K. (1990). Epidemiology of shoulder impingement in upper arm sports events. British Journal of Sports Medicine, 24(3), 173-177.
Lukasiewicz, McClure, Michener, Pratt, & Sennett. (1999). Comparison of 3-dimensional scapular position and orientation between subjects with and without shoulder impingement. Journal of Orthopaedic & Sports Physical Therapy, 29(10), 574-586.
Lyman, Fleisig, Waterbor, Funkhouser, Pulley, Andrews, . . . Roseman. (2001). Longitudinal study of elbow and shoulder pain in youth baseball pitchers. Medicine and Science in Sports and Exercise, 33(11), 1803-1810.
Maenhout, A., Dhooge, F., Van Herzeele, M., Palmans, T., & Cools, A. (2015). Acromiohumeral distance and 3-dimensional scapular position change after overhead muscle fatigue. Journal of Athletic Training, 50(3), 281-288.
Meijden, Westgard, P., Chandler, Z., Gaskill, T. R., Kokmeyer, D., & Millett, P. J. (2012). Rehabilitation after arthroscopic rotator cuff repair: current concepts review and evidence-based guidelines. International Journal of Sports Physical Therapy, 7(2), 197.
Meister, K. (2000a). Injuries to the shoulder in the throwing athlete. The American Journal of Sports Medicine, 28(4), 587.
Meister, K. (2000b). Injuries to the shoulder in the throwing athlete: part one: biomechanics/pathophysiology/classification of injury. The American Journal of Sports Medicine, 28(2), 265-275.
Meister, K. (2000c). Injuries to the shoulder in the throwing athlete: part two: evaluation/treatment. The American Journal of Sports Medicine, 28(4), 587-601.
Morgan, C. D., Burkhart, S. S., Palmeri, M., & Gillespie, M. (1998). Type II SLAP lesions: three subtypes and their relationships to superior instability and rotator cuff tears. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 14(6), 553-565.
Mullaney, M. J., McHugh, M. P., Donofrio, T. M., & Nicholas, S. J. (2005). Upper and lower extremity muscle fatigue after a baseball pitching performance. The American Journal of Sports Medicine, 33(1), 108-113.
Mullaney, M. J., Perkinson, C., Kremenic, I., Tyler, T. F., Orishimo, K., & Johnson, C. (2017). EMG of shoulder muscles during reactive isometric elastic resistance exercises. International Journal of Sports Physical Therapy, 12(3), 417.
Murray, Cook, Werner, Schlegel, & Hawkins. (2001). The effects of extended play on professional baseball pitchers. The American Journal of Sports Medicine, 29(2), 137-142.
Myers, J. B., Oyama, S., Rucinski, T. J., & Creighton, R. A. (2011). Humeral retrotorsion in collegiate baseball pitchers with throwing-related upper extremity injury history. Sports Health, 3(4), 383-389.
Nissen, C. W., Westwell, M., Õunpuu, S., Patel, M., Solomito, M., & Tate, J. (2009). A biomechanical comparison of the fastball and curveball in adolescent baseball pitchers. The American Journal of Sports Medicine, 37(8), 1492-1498.
Olsen, Fleisig, Dun, Loftice, & Andrews. (2006). Risk factors for shoulder and elbow injuries in adolescent baseball pitchers. The American Journal of Sports Medicine, 34(6), 905-912.
Olsen, Myklebust, Engebretsen, & Bahr. (2006). Injury pattern in youth team handball: a comparison of two prospective registration methods. Scandinavian Journal of Medicine & Science in Sports, 16(6), 426-432.
Page, P. (2011). Shoulder muscle imbalance and subacromial impingement syndrome in overhead athletes. International Journal of Sports Physical Therapy, 6(1), 51.
Petty, D. H., Andrews, J. R., Fleisig, G. S., & Cain, E. L. (2004). Ulnar collateral ligament reconstruction in high school baseball players: clinical results and injury risk factors. The American Journal of Sports Medicine, 32(5), 1158-1164.
Pieper, H.-G., Quack, G., & Krahl, H. (1993). Impingement of the rotator cuff in athletes caused by instability of the shoulder joint. Knee Surgery, Sports Traumatology, Arthroscopy, 1(2), 97-99.
Reinold, M. M., Macrina, L. C., Wilk, K. E., Fleisig, G. S., Dun, S., Barrentine, S. W., . . . Andrews, J. R. (2007). Electromyographic analysis of the supraspinatus and deltoid muscles during 3 common rehabilitation exercises. Journal of Athletic Training, 42(4), 464.
Richards, R. R., An, K.-N., Bigliani, L. U., Friedman, R. J., Gartsman, G. M., Gristina, A. G., . . . Zuckerman, J. D. (1994). A standardized method for the assessment of shoulder function. Journal of Shoulder and Elbow Surgery, 3(6), 347-352.
Sabick, M. B., Kim, Y.-K., Torry, M. R., Keirns, M. A., & Hawkins, R. J. (2005). Biomechanics of the shoulder in youth baseball pitchers: implications for the development of proximal humeral epiphysiolysis and humeral retrotorsion. The American Journal of Sports Medicine, 33(11), 1716-1722.
Stodden, Fleisig, McLean, & Andrews. (2005). Relationship of biomechanical factors to baseball pitching velocity: within pitcher variation. Journal of Applied Biomechanics, 21(1), 44-56.
Stodden, Fleisig, McLean, Lyman, & Andrews. (2001). Relationship of pelvis and upper torso kinematics to pitched baseball velocity. Journal of Applied Biomechanics, 17(2), 164-172.
Torg, J. S., Pollack, H., & Sweterlitsch, P. (1972). The effect of competitive pitching on the shoulders and elbows of preadolescent baseball players. Pediatrics, 49(2), 267-272.
Tripp, B. L., Yochem, E. M., & Uhl, T. L. (2007a). Functional fatigue and upper extremity sensorimotor system acuity in baseball athletes. Journal of Athletic Training, 42(1), 90.
Tripp, B. L., Yochem, E. M., & Uhl, T. L. (2007b). Recovery of upper extremity sensorimotor system acuity in baseball athletes after a throwing-fatigue protocol. Journal of Athletic Training, 42(4), 452.
Urbin, Fleisig, Abebe, & Andrews. (2013). Associations between timing in the baseball pitch and shoulder kinetics, elbow kinetics, and ball speed. The American Journal of Sports Medicine, 41(2), 336-342.
Werner, S. L., Fleisig, G. S., Dillman, C. J., & Andrews, J. R. (1993). Biomechanics of the elbow during baseball pitching. Journal of Orthopaedic & Sports Physical Therapy, 17(6), 274-278.
Werner, S. L., Gill, T. J., Murray, T. A., Cook, T. D., & Hawkins, R. J. (2001). Relationships between throwing mechanics and shoulder distraction in professional baseball pitchers. The American Journal of Sports Medicine, 29(3), 354-358.
Wilk, Andrews, & Arrigo. (2001). Preventive and rehabilitative exercises for the shoulder and elbow. American Sports Medicine Institute. 6th ed. Birmingham, AL.
Wilk, Meister, & Andrews. (2002). Current concepts in the rehabilitation of the overhead throwing athlete. The American Journal of Sports Medicine, 30(1), 136-151.
Wu, G., Van der Helm, F. C., Veeger, H. D., Makhsous, M., Van Roy, P., Anglin, C., . . . Wang, X. (2005). ISB recommendation on definitions of joint coordinate systems of various joints for the reporting of human joint motion—Part II: shoulder, elbow, wrist and hand. Journal of Biomechanics, 38(5), 981-992.
Wilk, K. E., Obma, P., Simpson, C. D., Cain, E. L., Dugas, J. R., & Andrews, J. R. (2009). Shoulder injuries in the overhead athlete. Journal of Orthopaedic & Sports Physical Therapy, 39, 38-54.