The Relationship Between Pitching Mechanics and Injury a Review of Current Concepts

• Journal List
• Sports Wellness
• 5.ix(iii); May-Jun 2017
• PMC5435152

Sports Wellness. 2017 May-Jun; 9(three): 216–221.

The Relationship Between Pitching Mechanics and Injury: A Review of Current Concepts

Peter N. Chalmers, Md,^* Markus A. Wimmer, PhD, Nikhil N. Verma, MD, Brian J. Cole, Doctor, MBA, Anthony A. Romeo, MD, Gregory Fifty. Cvetanovich, MD, Michael Fifty. Pearl, MD, Peter N. Chalmers, Dr., Markus A. Wimmer, PhD, Nikhil N. Verma, MD, Brian J. Cole, Doctor, MBA, Anthony A. Romeo, Doc, Gregory L. Cvetanovich, Medico, and Michael L. Pearl, MD

Abstract

Context:

The overhand pitch is i of the fastest known man motions and places enormous forces and torques on the upper extremity. Shoulder and elbow pain and injury are common in loftier-level pitchers. A big body of enquiry has been conducted to understand the pitching motion.

Show Acquisition:

A comprehensive review of the literature was performed to proceeds a total understanding of all currently bachelor biomechanical and clinical evidence surrounding pitching motion assay. These motion analysis studies employ video motion analysis, electromyography, electromagnetic sensors, and markered motion analysis. This review includes studies performed between 1983 and 2016.

Study Design:

Clinical review.

Level of Evidence:

Level five.

Results:

The pitching motion is a kinetic concatenation, in which the force generated past the large muscles of the lower extremity and trunk during the wind-up and pace phases are transferred to the brawl through the shoulder and elbow during the cocking and dispatch phases. Numerous kinematic factors take been identified that increase shoulder and elbow torques, which are linked to increased take chances for injury.

Decision:

Altered knee flexion at brawl release, early trunk rotation, loss of shoulder rotational range of motion, increased elbow flexion at ball release, loftier pitch velocity, and increased pitcher fatigue may increase shoulder and elbow torques and risk for injury.

Keywords: glenoid labrum, biceps tendon, baseball game/softball, move analysis/kinesiology, superior labral anterior posterior (SLAP) tear

Overhand baseball pitching is one of the fastest known human motions.⁵² Pitching places exceptional forces and torques on the upper extremity.^22,23,52 As a consequence, pitching-related shoulder and elbow pain is highly prevalent at up to 46% to 57% of pitchers.³⁴ Considerable inquiry has focused on pitching motion assay to provide insight into the mechanisms of these injuries. The objective of this review is to describe the relationship betwixt pitching mechanics and injury.

Basics of Motility Analysis

Motion analysis allows the calculation of in vivo kinetics. Within the upper extremity, kinetics are derived from inverse dynamics,¹⁹ which assume the human being body is composed of inflexible segments linked at joints. Markered movement analysis with reflective markers has been used for virtually pitching motion analysis because of the accuracy, speed, and ease of data collection.^28,36,38,45 However, these systems are subject to several important limitations.

Limitations of Motion Assay

Motion analysis has several important limitations. Variations in laboratory setup, marker placement, sampling rate, synchronization, calibration, and software assumptions can create pregnant mistake. Minor variations in marker placement can create large variations in kinematic output within the organization.³⁸ This factor has been identified as the single largest source of variability.²⁸ Even with this precaution, these markers are affixed to the pare, which tin move with respect to the bones during rapid motions. In ane review, comparison of bone pins to skin markers during running revealed 63% to 70% average error for rotation and abduction/adduction motions.⁴⁵ These factors likely explicate the wide variation in the reported reliability of 3-dimensional move analysis.³⁶

Electromyography

Muscular activation can exist measured with electromyography in synchrony with pitcher move.^{eight,11,thirteen,18,27,29,30,49,l,55} Understanding these patterns may help to place at-take a chance pitchers and rehabilitate injured pitchers.^xi,26,27 These studies have demonstrated that pitching requires whole-body coordination, with precisely timed and balanced muscular coactivation of nearly every muscle group, including antagonists from the lower extremity,^8,55 to the trunk,^fifty shoulder musculature,^{11,18,27,29,30} and forearm musculature.^13,49 These results^26,27 advise that neuromuscular activation plays a disquisitional role in the normal pitching motion.

Basics of The Pitching Motility

The overhand pitch is a tightly timed motion that transfers torque generated largely past the lower extremity and cadre musculature with the footstep, pelvic rotation, and torso rotation through the upper extremity. The overhand pitch is a kinetic chain^xix in which each subsequent segment receives the potential and kinetic free energy received and generated by the previous segment. These segments are governed by the summation of speed principle¹ in which energy transfer is optimized when the subsequent segment begins rotating as the prior segment has reached maximal angular velocity.⁴⁴ In the existent world, rotational timing is ordinarily imperfect.¹⁷

The pitch has been traditionally divided into vi phases: (1) wind-up, (two) stride, (3) cocking, (iv) dispatch, (5) deceleration, and (6) follow-through. Each phase serves a specific office. The phases can be defined based on major events during the pitch (Effigy 1).^14,22,23,51

Phases of the pitch for a left-handed bullpen: (a) wind-upwardly, (b) stride, (c) cocking, (d) dispatch, (e) deceleration, (f) follow-through, and (g) end of the pitch.

1. Wind-upwardly: This phase positions the body in preparation for force generation. The hands are brought together to the chest and the pitcher lifts the lead leg.^xiv,22,23,51

2. Stride: Initiates velocity generation through linear forward motion and positions the arm in the cocking position. The lag foot remains planted while the lead foot moves forward and down the mound, with the hip and articulatio genus extending. As this peaks, the pelvis also rotates to face domicile plate.^14,22,23,51

3. Cocking: Transfers energy from the lower extremity and core into potential energy stored in the shoulder capsule. Begins with front foot strike and paw separation. The shoulder remains abducted xc° while externally rotating up to 180° through both the glenohumeral and scapulothoracic joints.^xiv,22,23,51 The trunk rotates toward habitation plate, receiving the energy transferred from the pelvis.⁴³ Tardily within this stage, shoulder rotational torque and elbow valgus torque height^2,3,22,40 (this moment in the pitch may be critical for superior labral anterior posterior [SLAP] tears and ulnar collateral ligament [UCL] tears).^4,7

4. Acceleration: Transfers all the energy generated inside the body onto the baseball. The shoulder internally rotates using the potential energy stored inside the capsule as well equally explosive power within the internal rotators. The elbow extends and the wrist flexes, imparting farther velocity on the ball.^{fourteen,22,23,43,51}

5. Deceleration: Slows downward arm movement beginning with ball release. The arm continues to internally rotate, although with decreasing angular velocity.^14,22,23,51 Shoulder proximal or compressive forcefulness peaks at several times torso weight as the rotator gage resists the distractive momentum of the arm.^16,22

6. Follow-though: Returns the torso to a fielding position in preparation for the next play.^{14,22,23,43,51}

Pitching Mechanics and Injury

Evidence is divided into empirical clinical information that have informed subsequent motion analysis studies for lower extremity, core and torso, shoulder, elbow, pitch velocity, and pitcher fatigue.

In a i-year empirical prospective written report of 476 youth baseball game pitchers—172 with video motion analysis—no motion analysis factor could be linked to injury.³⁴ In a 3-year prospective study with video motion analysis of 23 professional baseball pitchers, there was a pregnant human relationship betwixt elbow injury and elbow valgus torque and shoulder maximum external rotation torque.^three Currently, no prospective clinical prove exists to connect shoulder proximal strength with rotator cuff tears,^22,52 shoulder rotational forces with proximal humeral epiphysiolysis,⁴⁶ or shoulder rotational torques with internal impingement.^v Studies have linked velocity to elbow valgus torque^xx and pitching injury (Table 1).⁴¹ While kinetic factors such as elbow valgus torque are difficult to measure, kinematic factors can be readily and inexpensively measured with video movement analysis and are more hands understood. These factors are changeable for injury prevention past pitchers and coaches (Table ii). As a upshot, numerous motion assay studies have been conducted to place kinematic correlates (such equally elbow flexion bending) with kinetic factors (such as elbow valgus torque and humeral rotational torque) (Figure 2). The most frequently identified factors include knee flexion at front foot contact,^{2,15,32,37,47,48} body rotational timing (Effigy three),^1,31 shoulder rotation,^2,48 and elbow flexion at ball release.^{2,14,32,47,48}

Tabular array i.

Quantitative kinematic factors from a variety of laboratories ^a

	Age, y	Knee joint flexion at front pes contact, deg	Trunk rotation timing, % of the pitch	Maximum shoulder external rotation, deg	Shoulder abduction at max external rotation, deg	Elbow flexion at brawl release, deg
Collegiate/Professional person Studies
Aguinaldo and Chambers2	20 ± 2	NA	−1 ± 28 (onset)	169 ± xvi	NA	41 ± 24
Fleisig et al24	twenty ± one	38 ± nine	50 ± 9 (max)	178 ± 7	NA	29 ± half dozen
Werner et al53	xx ± 2	47 ± 15	NA	158 ± 10	NA	57 ± 13
Youth Studies
Nissen et al39	12	NA	35 ± vi (max)	168 ± 10	66 ± 17	39 ± ten
Sabick et al48	12 ± 0.iv	NA	NA	166 ± 9	92 ± viii	25 ± 14

Table 2.

Quantitative kinetic factors from a diversity of laboratories ^a

	Shoulder internal rotation torque, N·g	Shoulder proximal force, N	Elbow varus torque, N·chiliad
Collegiate/Professional Studies
Aguinaldo and Chambers2	NA	NA	50 ± 29
Fleisig et al24	84 ± 13	1056 ± 157	82 ± 13
Werner et al53	NA	81 ± 10% BW	3 ± 1% BW*Ht
Youth Studies
Nissen et al39	27 ± 112	NA	27 ± 12
Sabick et al48	NA	NA	18 ± 4

The three kinetic factors shown to correlate with injury: elbow valgus torque (a), shoulder external rotation torque (b), and pitch velocity (c).

Two pitchers each at the moment of front foot contact. Marked differences can be seen in thoracic rotation, between (a) rotation thirty° toward the pitchers and (b) rotation 45° toward 2d base. The axes for the surroundings are shown in red (x), blue (y), and yellow (z).

Within the lower extremity, articulatio genus flexion at forepart foot contact correlates with shoulder and elbow torques.^fifteen,37 This angle is consequent between subjects and may be an adaptive factor for continued high-velocity pitching in older pitchers.^{2,15,32,37,47,48} Knee flexion at front foot contact increased from 38.five° to 43.viii° as pitchers anile from <20 years one-time to >27 years quondam.^xv Genu flexion at human foot strike is critical to allow force transfer from the powerful stride up the kinetic chain. Alteration of knee flexion at ball release probable impacts pelvic, torso, and shoulder rotational timing, which likely propagates upwards the kinetic chain to translate into college shoulder and elbow torques.^{2,15,32,37,47,48}

Contempo clinical studies advise that body rotational timing may be linked to injury.^one,31 In a comparison of normal controls, SLAP repairs had altered thoracic rotation.¹¹ Improper trunk rotational timing correlates with higher peak elbow valgus loadⁱⁱ likewise equally college shoulder proximal force and shoulder external rotational angle.⁴² Desynchronization of trunk timing with stride and pelvic rotation may lead the superlative of potential free energy to pass through the shoulder and elbow.^1,31 Desynchronization of rotational timing between the pelvis and the torso has been described by pitching coaches as "flying open at the shoulders" or defective "hip and shoulder separation."¹²

While glenohumeral internal rotational deficit is a chief risk factor for injury,⁶ loss of total rotational range of motion may be the critical injury factor.⁵⁴ The complementary side of glenohumeral internal rotational deficit is glenohumeral external rotation excess, which may be linked to increased elbow valgus load,^2,48 SLAP tears,⁵ and UCL tears.²⁵ Improving shoulder external rotation is a crucial target for rehabilitation after injury.³³

Elbow flexion angle at ball release correlates with shoulder and elbow kinetics and varies little betwixt pitchers.^{2,14,32,47,48} Small changes tin alter the lever arm between the forearm and the humerus. ^{2,14,32,47,48} Elbow flexion increases the length of the lever arm, the inertial moment of humeral rotation, and elbow valgus torques and strain on the UCL.^{2,14,32,47,48}

From a holistic perspective, pitching velocity and fatigue are injury predictors.⁸ Higher pitch velocity is the best predictive factor of UCL reconstruction in Major League Baseball pitchers.⁹ Several prospective studies have too identified fatigue as a risk gene for injury.^21,34,56 Based on these findings, Usa Baseball, Little League America, and Major League Baseball have all developed age-based guidelines regarding residual and pitch counts (Tabular array 3). These guidelines focus on proper pitch mechanics to reduce shoulder and elbow torque.³⁵ Pitch velocity correlates with pitching injury in youth pitchers.^ten

Table 3.

Current Major League Baseball Pitch Smart recommendations³⁵

Age, y	Maximum Daily Pitch Count	No. of Days Residual Required past Pitch Count
		0	1	2	iii	iv
7-viii	50	1-20	21-35	36-50	NA	NA
9-10	75				51-65	66+
eleven-12	85
13-14	95
15-16	95	1-xxx	31-45	46-lx	61-75	76+
17-18	105
19-22	120

Ane method to combine pitch velocity with motion analysis is to summate "pitching efficiency."¹² This concept was recently used in a qualitative move analysis report of the pitching motion. Pitchers with proper hip and shoulder separation and the hand-on-top position demonstrated improved pitching efficiency.¹²

In conclusion, several mechanical factors correlate with pitch injury: elbow valgus torque, knee flexion at front foot contact, bullpen fatigue, early on thoracicc of the hips and shoulders, and decrease in shoulder rotational range of motion. These factors can decrease pitch velocity and produce bullpen fatigue, leading to injury.

Footnotes

The following authors declared potential conflicts of interest: Markus A. Wimmer, PhD, has grants/grants pending from Biomet, Ceramtec, and Zimmer. Nikhil North. Verma, MD, is a paid consultant for Smith and Nephew; receives royalties from Arthroscopy, Vindico, and Smith and Nephew; and has stock/stock options in Cymedica, Minivasive, and Omeros. Brian J. Cole, Medico, MBA, is a paid consultant for Arthrex, Regentis, and Zimmer; receives royalties from Arthrex, DJ Orthopaedics, Elsevier, Saunders, and SLACK; and has stock/stock options in Carticept and Regentis. Anthony A. Romeo, Doctor, is a paid consultant for, and received payment for lectures from, Arthrex, and besides receives royalties from Arthrex and Saunders.

References

1. Aguinaldo AL, Buttermore J, Chambers H. Furnishings of upper trunk rotation on shoulder joint torque amongst baseball pitchers of diverse levels. J Appl Biomech. 2007;23:42-51. [PubMed] [Google Scholar]

2. Aguinaldo AL, Chambers H. Correlation of throwing mechanics with elbow valgus load in adult baseball pitchers. Am J Sports Med. 2009;37:2043-2048. [PubMed] [Google Scholar]

three. Anz AW, Bushnell BD, Griffin LP, Noonan TJ, Torry MR, Hawkins RJ. Correlation of torque and elbow injury in professional person baseball pitchers. Am J Sports Med. 2010;38:1368-1374. [PubMed] [Google Scholar]

4. Bey MJ, Elders GJ, Huston LJ, Kuhn JE, Blasier RB, Soslowsky LJ. The machinery of creation of superior labrum, inductive, and posterior lesions in a dynamic biomechanical model of the shoulder: the office of inferior subluxation. J Shoulder Elbow Surg. 1998;vii:397-401. [PubMed] [Google Scholar]

five. Braun Southward, Kokmeyer D, Millett PJ. Shoulder injuries in the throwing athlete. J Bone Joint Surg Am. 2009;91:966-978. [PubMed] [Google Scholar]

6. Burkhart SS, Morgan CD. The peel-dorsum mechanism: its office in producing and extending posterior type Two SLAP lesions and its effect on SLAP repair rehabilitation. Arthroscopy. 1998;14:637-640. [PubMed] [Google Scholar]

7. Burkhart SS, Morgan CD, Kibler WB. Shoulder injuries in overhead athletes. The "expressionless arm" revisited. Clin Sports Med. 2000;19:125-158. [PubMed] [Google Scholar]

8. Campbell BM, Stodden DF, Nixon MK. Lower extremity musculus activation during baseball pitching. J Force Cond Res. 2010;24:964-971. [PubMed] [Google Scholar]

9. Chalmers PN, Erickson BJ, Brawl B, Romeo AA, Verma NN. Fastball pitch velocity helps predict ulnar collateral ligament reconstruction in Major League Baseball Pitchers. Am J Sports Med. 2016;44:2130-2135. [PubMed] [Google Scholar]

10. Chalmers PN, Sgroi T, Riff AJ, et al. Correlates with history of injury in youth and adolescent pitchers. Arthroscopy. 2015;31:1349-1357. [PubMed] [Google Scholar]

11. Chalmers PN, Trombley R, Cip J, et al. Postoperative restoration of upper extremity motion and neuromuscular control during the overhand pitch: evaluation of tenodesis and repair for superior labral inductive-posterior tears. Am J Sports Med. 2014;42:2825-2836. [PubMed] [Google Scholar]

12. Davis JT, Limpisvasti O, Fluhme D, et al. The result of pitching biomechanics on the upper extremity in youth and adolescent baseball pitchers. Am J Sports Med. 2009;37:1484-1491. [PubMed] [Google Scholar]

xiii. DiGiovine NM, Jobe FW, Pink M, Perry J. An electromyographic analysis of the upper extremity in pitching. J Shoulder Elbow Surg. 1992;1:15-25. [PubMed] [Google Scholar]

14. Dillman CJ, Fleisig GS, Andrews JR. Biomechanics of pitching with emphasis upon shoulder kinematics. J Orthop Sports Phys Ther. 1993;eighteen:402-408. [PubMed] [Google Scholar]

15. Dun S, Fleisig GS, Loftice J, Kingsley D, Andrews JR. The relationship between historic period and baseball pitching kinematics in professional baseball game pitchers. J Biomech. 2007;twoscore:265-270. [PubMed] [Google Scholar]

16. Dun S, Loftice J, Fleisig GS, Kingsley D, Andrews JR. A biomechanical comparison of youth baseball game pitches: is the curveball potentially harmful? Am J Sports Med. 2008;36:686-692. [PubMed] [Google Scholar]

17. Elliot B, Grove J, Gibson B. Timing of the lower limb drive and throwing limb movement in baseball pitching. Int J Sport Biomech. 1988;four:59-67. [Google Scholar]

18. Escamilla RF, Andrews JR. Shoulder muscle recruitment patterns and related biomechanics during upper extremity sports. Sports Med. 2009;39:569-590. [PubMed] [Google Scholar]

19. Feltner ME, Dapena J. Three-dimensional interactions in a two-segment kinetic chain. Part 1: general model. Int J Sports Biomech. 1989;v:403-419. [Google Scholar]

20. Fleisig GS, Andrews JR, Cutter GR, et al. Risk of serious injury for immature baseball pitchers: a 10-year prospective written report. Am J Sports Med. 2011;39:253-257. [PubMed] [Google Scholar]

21. Fleisig GS, Andrews JR, Dillman CJ, Escamilla RF. Kinetics of baseball game pitching with implications about injury mechanisms. Am J Sports Med. 1995;23:233-239. [PubMed] [Google Scholar]

22. Fleisig GS, Barrentine SW, Escamilla RF, Andrews JR. Biomechanics of overhand throwing with implications for injuries. Sports Med. 1996;21:421-437. [PubMed] [Google Scholar]

23. Fleisig G, Chu Y, Weber A, Andrews JR. Variability in baseball pitching biomechanics amid various levels of competition. Sports Biomech. 2009;eight:x-21. [PubMed] [Google Scholar]

24. Fleisig GS, Kingsley DS, Loftice JW, et al. Kinetic comparison among the fastball, curveball, change-up, and slider in collegiate baseball pitchers. Am J Sports Med. 2006;34:423-430. [PubMed] [Google Scholar]

25. Garrison JC, Arnold A, Macko MJ, Conway JE. Baseball players diagnosed with ulnar collateral ligament tears demonstrate decreased rest compared to healthy controls. J Orthop Sports Phys Ther. 2013;43:752-758. [PubMed] [Google Scholar]

26. Glousman R, Jobe F, Tibone J, Moynes D, Antonelli D, Perry J. Dynamic electromyographic analysis of the throwing shoulder with glenohumeral instability. J Os Articulation Surg Am. 1988;70:220-226. [PubMed] [Google Scholar]

27. Glousman RE, Barron J, Jobe FW, Perry J, Pink M. An electromyographic analysis of the elbow in normal and injured pitchers with medial collateral ligament insufficiency. Am J Sports Med. 1992;20:311-317. [PubMed] [Google Scholar]

28. Gorton GE, Hebert DA, Gannotti ME. Cess of the kinematic variability among 12 motion analysis laboratories. Gait Posture. 2009;29:398-402. [PubMed] [Google Scholar]

29. Jobe FW, Moynes DR, Tibone JE, Perry J. An EMG assay of the shoulder in pitching: a second report. Am J Sports Med. 1984;12:218-220. [PubMed] [Google Scholar]

30. Jobe FW, Tibone JE, Perry J, Moynes D. An EMG assay of the shoulder in throwing and pitching: a preliminary report. Am J Sports Med. 1983;11:3-5. [PubMed] [Google Scholar]

31. Keeley DW, Hackett T, Keirns 1000, Sabick MB, Torry MR. A biomechanical analysis of youth pitching mechanics. J Pediatr Orthop. 2008;28:452-459. [PubMed] [Google Scholar]

32. Keeley DW, Wicke J, Alford Thousand, Oliver GD. Biomechanical analysis of forearm pronation and its relationship to brawl movement for the two-seam and four-seam fastball pitches. J Strength Cond Res. 2010;24:2366-2371. [PubMed] [Google Scholar]

33. Laughlin WA, Fleisig GS, Scillia AJ, Aune KT, Cain EL, Dugas JR. Deficiencies in pitching biomechanics in baseball game players with a history of superior labrum anterior-posterior repair. Am J Sports Med. 2014;42:2837-2841. [PubMed] [Google Scholar]

34. Lyman S, Fleisig GS, Andrews JR, Osinski ED. Outcome of pitch type, pitch count, and pitching mechanics on risk of elbow and shoulder pain in youth baseball game pitchers. Am J Sports Med. 2002;30:463-468. [PubMed] [Google Scholar]

35. Major League Baseball Advisory Commission. Pitch Smart Guidelines. Pitch Smart. Published Feb nineteen, 2015. http://m.mlb.com/pitchsmart/. Accessed March 30, 2015.

36. McGinley JL, Bakery R, Wolfe R, Morris ME. The reliability of three-dimensional kinematic gait measurements: a systematic review. Gait Posture. 2009;29:360-369. [PubMed] [Google Scholar]

37. Milewski MD, Õunpuu South, Solomito M, Westwell M, Nissen CW. Boyish baseball pitching technique: lower extremity biomechanical assay. J Appl Biomech. 2012;28:491-501. [PubMed] [Google Scholar]

38. Morton NA, Maletsky LP, Pal S, Laz PJ. Effect of variability in anatomical landmark location on knee kinematic description. J Orthop Res. 2007;25:1221-1230. [PubMed] [Google Scholar]

39. Nissen CW, Westwell M, Õunpuu Due south, et al. Adolescent baseball game pitching technique: a detailed three-dimensional biomechanical analysis. Med Sci Sports Exerc. 2007;39:1347-1357. [PubMed] [Google Scholar]

40. Nissen CW, Westwell M, Õunpuu S, Patel M, Solomito M, Tate J. A biomechanical comparing of the fastball and curveball in adolescent baseball pitchers. Am J Sports Med. 2009;37:1492-1498. [PubMed] [Google Scholar]

41. Olsen SJ, Fleisig GS, Dun S, Loftice J, Andrews JR. Chance factors for shoulder and elbow injuries in adolescent baseball game pitchers. Am J Sports Med. 2006;34:905-912. [PubMed] [Google Scholar]

42. Oyama S, Yu B, Blackburn JT, Padua DA, Li 50, Myers JB. Improper trunk rotation sequence is associated with increased maximal shoulder external rotation angle and shoulder joint force in high school baseball pitchers. Am J Sports Med. 2014;42:2089-2094. [PubMed] [Google Scholar]

43. Pappas AM, Zawacki RM, Sullivan TJ. Biomechanics of baseball game pitching. A preliminary report. Am J Sports Med. 1985;13:216-222. [PubMed] [Google Scholar]

44. Putnam CA. Sequential motions of trunk segments in striking and throwing skills: descriptions and explanations. J Biomech. 1993;26(suppl 1):125-135. [PubMed] [Google Scholar]

45. Reinschmidt C, van den Bogert AJ, Nigg BM, Lundberg A, Murphy N. Effect of skin motion on the analysis of skeletal knee joint motion during running. J Biomech. 1997;30:729-732. [PubMed] [Google Scholar]

46. Sabick MB, Kim Y-Grand, Torry MR, Keirns MA, Hawkins RJ. Biomechanics of the shoulder in youth baseball pitchers: implications for the evolution of proximal humeral epiphysiolysis and humeral retrotorsion. Am J Sports Med. 2005;33:1716-1722. [PubMed] [Google Scholar]

47. Sabick MB, Torry MR, Kim Y-K, Hawkins RJ. Humeral torque in professional baseball pitchers. Am J Sports Med. 2004;32:892-898. [PubMed] [Google Scholar]

48. Sabick MB, Torry MR, Lawton RL, Hawkins RJ. Valgus torque in youth baseball game pitchers: a biomechanical study. J Shoulder Elbow Surg. 2004;thirteen:349-355. [PubMed] [Google Scholar]

49. Sisto DJ, Jobe FW, Moynes DR, Antonelli DJ. An electromyographic analysis of the elbow in pitching. Am J Sports Med. 1987;xv:260-263. [PubMed] [Google Scholar]

50. Watkins RG, Dennis S, Dillin WH, et al. Dynamic EMG analysis of torque transfer in professional baseball pitchers. Spine. 1989;xiv:404-408. [PubMed] [Google Scholar]

51. Werner SL, Fleisig GS, Dillman CJ, Andrews JR. Biomechanics of the elbow during baseball pitching. J Orthop Sports Phys Ther. 1993;17:274-278. [PubMed] [Google Scholar]

52. Werner SL, Gill TJ, Murray TA, Cook TD, Hawkins RJ. Relationships between throwing mechanics and shoulder distraction in professional baseball pitchers. Am J Sports Med. 2001;29:354-358. [PubMed] [Google Scholar]

53. Werner SL, Guido JA, Stewart GW, McNeice RP, VanDyke T, Jones DG. Relationships between throwing mechanics and shoulder distraction in collegiate baseball pitchers. J Shoulder Elbow Surg. 2007;xvi:37-42. [PubMed] [Google Scholar]

54. Wilk KE, Macrina LC, Fleisig GS, et al. Deficits in glenohumeral passive range of movement increase risk of elbow injury in professional baseball game pitchers: a prospective study. Am J Sports Med. 2014;42:2075-2081. [PubMed] [Google Scholar]

55. Yamanouchi T. EMG analysis of the lower extremities during pitching in high-schoolhouse baseball. Kurume Med J. 1998;45:21-25. [PubMed] [Google Scholar]

56. Yang J, Mann BJ, Guettler JH, et al. Run a risk-decumbent pitching activities and injuries in youth baseball: findings from a national sample. Am J Sports Med. 2014;42:1456-1463. [PubMed] [Google Scholar]

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