前言:
棒球投手常常在比賽時為求表現，強忍著疲累在承受投球動作所帶來的負荷，而肌力的衰退導致無法穩定投球動作，造成投球姿勢代償，在不適當的姿勢下繼續投球動作，除了影響投手的表現，更施加過度的壓力於肩及肘關節，提高了受傷的風險。過去研究指出運動過後肌力的衰退除了會有立即性的影響之外，更持續24~48小時之間。
目的:
探討牛棚投球訓練對台灣高中棒球投手在投球動作、肩及肘關節活動角度所帶來的立即影響與肌力衰退的相關性。
研究方法:
本實驗中投球動作分析的受測者共有13位；肌力與肩及肘關節活動角度量測的受測者共有14位。受測者完成熱身後立即進行前測實驗包括:使用三維動作分析系統擷取過肩投球(Overhead)動作的過程，接著以Biodex (isometric contraction)量測肩及肘關節附屬肌群肌力的衰退情形及使用關節角度量尺量測肩及肘關節活動角度以當作投球前之基準值(Baseline)，之後則是進行牛棚投球訓練(Bullpen Pitching Training)，投手結束牛棚投球訓練後，則繼續完成後測實驗的量測。牛棚投球訓練後兩天的實驗內投手皆不再進行投球動作，當投手完成熱身後立即量測肌力與肩及肘關節活動角度，並將前測(pre-test)、後測(post-test)，牛棚投球訓練後第一天(Day1)，牛棚投球訓練後第二天(Day2)所量測的數據以重複測量變異數分析做統計，設定P<0.05即達統計上顯著差異，以觀察衰退的情形。牛棚投球訓練前後動作分析的差異以配對t檢定分析，慣用手與非慣用手的差異則以獨立樣本t檢定分析，並皆設定P<0.05即達統計顯著差異。
結果:
選手完成牛棚投球訓練後在球離手(BR)時，肩關節外旋角度減少(p=0.023)、膝關節屈曲角度減少(p=0.046)，球速明顯下降(p=0.041)。在肌力方面，慣用手的肌力在肩關節屈曲(p=0.013)、肩關節伸展(p=0.005)、肩關節內旋(p=0.027)及肩關節外旋(p=0.034)比非慣用手大。牛棚投球訓練後慣用手在肩關節屈曲(p=0.007)、肩關節伸展(p=0.002)、肩關節外展(p=0.011)、肩關節內收(p=0.03)、肩關節內旋(p=0.003)及肩關節外旋(p=0.001)肌力有明顯的衰退；牛棚投球訓練後第一天肩關節屈曲(p=0.008)、肩關節外展(p=0.016)、肩關節內旋(p=0.004)、肩關節外旋(p=0.013)及肘關節屈曲(p=0.045)肌力仍有明顯的衰退；牛棚投球訓練後後第二天肩關節內旋(p=0.011)及肩關節外旋(p=0.009)肌力仍有明顯的衰退。
討論與結論：
牛棚投球訓練後肌力產生立即性的衰退，其中肩關節內、外旋肌力的衰退更持續24~48小時，肌力的衰退導致投球動作產生立即性的改變，造成投手控球能力及球速表現下降，通常也被當做是辨別投手疲勞的指標，因此期望由本研究結果去訂定疲勞的準則及體能訓練的參考，以提升國內青棒投手投球的表現及降低運動傷害的風險。

Backgrounds:
The increased risk of injury of baseball pitchers in the game usually resulted from the prolonged fatigue during pitching. And the decrease of muscle strength contributed to the instability of pitching posture. Inadequate pitching posture may lead to overpressure on the shoulder joint and elbow joint. Previous studies pointed out that the decrease of muscle strength after game may prolong 48 hours.
Purpose:
Considering the effect of simulated Bullpen Pitching Training in Taiwanese High School Pitcher, this study investigated the performance of the kinematics, muscle strength and range of motion on shoulder and elbow.
Methods:
Thirteen Taiwanese baseball pitchers from High school were adopted motion analysis before and after Bullpen Pitching Training. Fourteen Taiwanese baseball pitchers from High school were adopted measurement of muscle strength and range of motion before and after Bullpen Pitching Training.
Firstly, the 3D motion capture system recorded pitchers throwing overhead pitches, next the Biodex (isometric contraction) measured the muscle strength of shoulder and elbow, and the goniometer measured the range of motion of shoulder and elbow joints. Then the pitchers threw an average of 100 overhead pitches in the bullpen pitching training. After bullpen pitching training, perform the 3D motion capture and muscle strength and range of motion measurements. One day and two day after bullpen pitching training both does not perform pitching, only measure the muscle strength and range of motion. Repeated Measure One Way ANOVA were used to determine the decrease of pre-test, post-test, Day1 and Day2. Pair t-test was used to determine the difference from pre-pitching for post-pitching in pitching motion. Independent t-test was used to determine the difference in the dominant versus non-dominant arm. A P value of <.05 was deemed significant.
Results:
In the Ball release, ball velocity significantly decreased (p=0.041) and the degree significantly decreased in the shoulder external rotation (p=0.023) and knee flexion (p=0.046). In the muscle strength, the dominant arm showed significantly bigger than non-dominant arm in shoulder flexion(p=0.013) , shoulder abduction (p=0.005), shoulder internal rotation (p=0.027)and shoulder external rotation(p=0.034). After Bullpen Pitching Training, muscle strength significantly decreased in shoulder flexion(p=0.007),shoulder extension(p=0.002),shoulder abduction(p=0.011), shoulder adduction(p=0.03),shoulder internal rotation(p=0.003),shoulder external rotation(p=0.001).In the first day after bullpen pitching training, the muscle strength significantly decreased in shoulder flexion(p=0.008),shoulder abduction(p=0.016),shoulder internal rotation(p=0.004),shoulder external rotation(p=0.013).In the second day after bullpen pitching training, the muscle strength significantly decreased in shoulder internal rotation(p = 0.011),shoulder external rotation(p = 0.009).
Conclusion:
The decrease in muscle strength occurs after Bullpen Pitching Training. Notable decrease in muscle strength prolonged (24~48 hours) in the Shoulder internal rotation and Shoulder external rotation. The change of pitching posture due to decrease of muscle strength cause the weak pitching controllability and the decrease of ball velocity. Such above factor may be viewed as index of pitcher performance to fatigue. Our findings provide the reference to criterion on the fatigue effect of training to help adolescent pitcher elevating pitching performance and degrading injury risk.

[1] 盧英治.衝擊式訓練的理論與實際。大專體育，51: 95-101. 2000.
[2] Asmussen E, Petersen BF. Storage of elastic energy in skeletal muscles in man. Acta Physicl,Scand; 91: 385-392. 1974.
[3] Andrews JR, McCluskey GM, McLeod WD: Musculo-tendinous injuries of the shoulder and elbow in athletes. Athletic Training;11: 68-74. 1976.
[4] Alderink GJ, Kuck DJ. Isokinetic shoulder strength of high school and college-aged pitchers. J Orthop Sports Phys Ther; 7(4): 163-172. 1986.
[5] Andrews JR, Angelo RL. Shoulder arthroscopy for the throwing athlete. Tech Orthop; 3: 75-82. 1988.
[6] Brown LP. Upper extremity range of motion and isokinetic strength of the internal and external shoulder rotators in major league baseball players. Am J Sports Med; 16(6): 577-585. 1988.
[7] Bartlett LR, Storey MD, Simons BD. Measurement of upper extremity torque production and its relationship to throwing speed in competitive athlete. American Journal of Sports Medicine; 17:89-91. 1989.
[8] Barrentine SW, Takada Y, Fleisig GS , Zheng N,Andrews JR. Kinematics and EMG changes in baseball pitching during a simulated game. American Sports Medicine Institute, Birmingham. 1997.
[9] Cheung K, Hume PA, Maxwell L. Delayed Onset Muscle Soreness: Treatment Strategies and Performance Factors. Sports Medicine; 33(2): 145-164. 2003.
[10] Connolly DAJ, Sayers SP, McHugh MP.Treatment and prevention of Delayed Onset Muscle Soreness. Journal of Strength and Conditioning Research; 17(1): 197-208. 2003.
[11] Donatelli R, Ellenbecker TS, Ekedahl SR, Wilkes JS, Kocher K, Adam J. Assessment of shoulder strength in professional baseball pitchers. J Orthop Sports Phys Ther; 30(9): 544-551. 2000.
[12] DiGiovine NM. An electromyographic analysis of the upper extremity in pitching. Journal of Shoulder and Elbow Surgery 1: 15–25. 2002.
[13] Dailsaku Hirayama, Norihisa Fujii. The kinematic changes of pitching during a simulated baseball game. ASB 29th Annual Meeting, Cleveland, Ohio. July 31-August 5. 2005.
[14] Dale RB, John E, Ogletree T, Robert J, Phillip M. The Effects of Repetitive Overhead Throwing on Shoulder Rotator Isokinetic Work-Fatigue. Am J Sports Phys Ther; 2(2): 74–80. 2007.
[15] Escamilla RF, Fleisig GS, Barrentine SW,Andrews JR, Speer KP. Effects of Throwing Overweight and Underweight Baseballs on Throwing Velocity and Accuracy. Sports Med; 29 (4): 259-272. 2000.
[16] Escamilla RF.Pitching biomechanics as a pitcher approaches muscular fatigue during a simulated baseball game. Am J Sports Med; 35(1):23-33. 2007.
[17] Escamilla RF, Andrews JR. Shoulder muscle recruitment patterns and related biomechanics during upper extremity sports. Sports Med; 39(7): 569-90. 2009.
[18] Fleisig GS, Andrews JR, Dillman CJ, Escamilla RF. Kinetics of baseball pitching with implications about injury mechanisms. American Journal of Sports Medicine; 23(2):233-239. 1995.
[19] Fleisig GS, Excamilla RF, Andrews JR, Matsuo T, Satterwhite Y, Barrentine SW. Kinematic and kinetic comparison between baseball pitching and football passing. Journal of Applied Biomechanics ;12(2):207-224. 1996.
[20] Fleisig GS. Kinematic and kinetic comparison of baseball pitching among various levels of development. J Biomech; 32(12): 1371-1375. 1999.
[21] Gregory WH. Shoulder Fatigue Following a Pitching Bout: A Case Study examination of Time to Recovery. 2007- 2008.
[22] Helen J, Hislop JM. Daniels and Worthingham's Muscle Testing. 6th ed. 2002.
[23] Jobe FW,Tibone JE, Moynes DR. An EMG analysis of the shoulder in throwing and pitching:A preliminary report. Am J Sports Med; 11: 3-5. 1984.
[24] Jobe FW, Moynes DR, Tibone JE. An EMG analysis of the shoulder in pitching.A second report. Am J Sports Med; 12: 218-220. 1994.
[25] Kindall J. Baseball: Play the winning way. Lanham MD: Sports Illustrated Books. 1993.
[26] Kazuyuki I, Masahiro M, Yuichi H. Shoulder and Elbow Kinematics in Throwing of Young Baseball Players. Sports Biomech; 5(2):183-196. 2006.
[27] Keeley DW. A biomechanical analysis of youth pitching mechanics. J Pediatr Orthop; 28(4): 452-9. 2008.
[28] Larsson L, Grimby G, Karlsson J. Muscle strength and speed of movement in relation to age and muscle morphology. Journal of Applied Physiology: 451-456. 1979.
[29] Lyman S, Fleisig GS, Andrews JR, Osinski ED. Effect of pitch type, pitch count, and pitching mechanics on risk of elbow and shoulder pain in youth baseball pitchers. American Journal of Sports Medicine; 30(4):463-468. 2002.
[30] Murray TA. The effects of extended play on professional baseball pitchers. Am J Sports Med; 29(2): 137-142. 2001.
[31] Manske RC, Tajchman CS, Stranghoner TA, Ellenbecker TS. Difference in Isokinetic Torque Acceleration Energy of the Rotator Cuff: Competitive Male Pitchers Versus Male Nonathletes. Journal of Strength and Conditioning Research; 18(3): 447-450. 2004.
[32] Mullaney MJ. Upper and lower extremity muscle fatigue after a baseball pitching performance. Am J Sports Med; 33(1): 108-113. 2005.
[33] Nadler SF. Injury in a throwing athlete: understanding the kinetic chain. American Journal of Physical Medicine & Rehabilitation;83(1):79. 2004.
[34] Nissen CW. Adolescent baseball pitching technique: a detailed three-dimensional biomechanical analysis. Med Sci Sports Exerc; 39(8): 1347-57. 2007.
[35] Pappas AM, Zawacki RM, McCarthy CF: Rehabilitation of the pitching shoulder. Am J Sports Med; 13: 223-235. 1985.
[36] Pappas AM, Zawacki RM, Sullivan TJ. Biomechanics of baseball pitching. A preliminary report. American Journal of Sports Med; 13(4):216-222. 1985.
[37] Putnam CA. Sequential motions of body segments in striking and throwing skills:descriptions and explanations. Journal of Biomechanics; 26 Suppl 1: 125-135. 1993.
[38] Prentice WE. The shoulder complex. Arnheim’s Principles of Athletic Training (11th ed): 702-703. 2003.
[39] Reinold MM. Changes in shoulder and elbow passive range of motion after pitching in professional baseball players. Am J Sports Med; 36(3): 523-527. 2008.
[40] Snyder SJ, Karzel RP, Pizzo wD, Ferkel RD, Friedman MJ.SLAP lesions of the shoulder. Arthroscopy ; (6): 274-279. 1990.
[41] Sparto PJ, Parnianpour M, Reinsel TE, Simon S. The effect of fatigue on multijoint kinematics and load sharing during a repetitive lifting test. Biomedical Engineering Center, The Ohio State University, Columbus 43210, USA. Spine (Phila Pa 1976). Nov 15; 22(22): 2647-2654. 1997.
[42] Sabick MB, Torry MR, Lawton RL, Hawkins RJ. Valgus torque in youth baseball pitchers: A biomechanical study. Journal of Shoulder & Elbow Surgery; 13(3):349-355. 2004. [43] Werner SL, Fleisig GS, Dillman CJ. Biomechanics of the elbow during baseball pitching. J Orthop Sports Phs Ther 17:274-278. 1993.
[44] Werner SL, Murray TA, Hawkins RJ, Gill TJ. Relationship between throwing mechanics and elbow valgus in professional baseball pitchers. Journal of Shoulder& Elbow Surgery; 11(2): 151-155. 2002.