Examining the relationship between different pitching mechanics and throwing injuries Zachary McCarthy Masters in Athletic Training Student Faculty Mentor: Valerie Moody

Overview Literature Review Focusing on the 6 phases of the throwing cycle Throwing injuries associated with each phase Different types of throwing injuries Recommendations to prevent injury

Phases of Throwing Cycle 6 phases of the throwing cycle Wind-up (WU) Early Cocking (EC) Late Cocking (LC) Acceleration (AC) Deceleration (DC) Follow-Through (FT)

Common Injuries during Throwing Cycle Investigated baseball pitching kinematics & joint loads during each phase of the throwing cycle. Each phase places different stresses on the tissues in the body Found no significant stresses or injuries associated with the WU or FT Early Cocking Anterior Instability & Posterior Impingement Late Cocking SLAP lesions, subacromial impingement, UCL sprain, medial epicondylitis Acceleration Biceps tendinopathy, rotator cuff strain, UCL sprain Deceleration Biceps tendinopathy, SLAP lesion, subacromial impingement Oyama S. Baseball pitching kinematics, joint loads, and injury prevention. Journal of Sport and Health Science. 2012;1(2):80-91.

Oyama S. Baseball pitching kinematics, joint loads, and injury prevention. Journal of Sport and Health Science. 2012;1(2):80-91.

Common Throwing Injuries UCL pathology Occurrences of UCL tears have increased over the past 10 years 2000-2011 = 16 per season / 2011-2014 = 26 per season UCL reconstructions are increasing in high school baseball Petty et al. indicated doubling rate compared to little league Less common in adolescents SLAP tears Late Cocking phase is associated with SLAP Little League Shoulder Overload injury to the proximal humeral epiphysis Shanley E, Thigpen C. Throwing Injuries in the Adolescent Athlete. The International Journal of Sports Physical Therapy. 2013;8(5):630-640.

UCL Injuries Anterior Band is primary soft tissue stabilizer for valgus stress ~ 64 Nm of valgus torque through elbow is produced every pitch Kinetic Chain produces 64 Nm of varus torque before ER Equivalent to holding 150 baseballs Ultimate valgus torque of the UCL is ~33 Nm to failure Every pitch the UCL experiences maximum torque which can lead to failure Ciccotti M, Atanda A, Nazarian L, Dodson C, Holmes L, Cohen S. Stress Sonography of the Ulnar Collateral Ligament of the Elbow in Professional Baseball Pitchers. The American Journal of Sports Medicine. 2014;42(3):544-551.

SLAP Tears Has been implicated this can be caused by overuse Position of LC increases the likely hood of the “peel back” mechanism of a SLAP lesion Mihata et al. Weak or fatigued subscapularis may contribute to the peel back mechanism Wolf B, Wolstenholme K. Throwing injuries: biomechanics, injury mechanisms and rehabilitation. Current Orthopaedic Practice. 2010;21(5):467-471.

Little League Shoulder Proximal humeral epiphysiolysis Commonly seen in adolescents (11- 15 yrs) Seen in pitchers who have thrown or pitched in high quantity Similar to Salter-Harris injury After symptoms disperse kids who are experiencing LLS had continuing widening of the proximal epiphysis Zaremski J, Krabak B. Shoulder Injuries in the Skeletally Immature Baseball Pitcher and Recommendations for the Prevention of Injury. PM&R. 2012;4(7):509-516. Heyworth B, Kramer D, Martin D, Micheli L, Kocher M, Bae D. Trends in the Presentation, Management, and Outcomes of Little League Shoulder. The American Journal of Sports Medicine. 2016;44(6):1431-1438.

Demographic Commonly Impacted by Injury Playing Baseball Majority of the 11.5 million athletes playing baseball in the U.S compete at high school level 2005-2007 130,000 high school baseball injuries More than 17% were shoulder injuries Adolescent to high school are affected more than MLB Epiphyseal plates don’t completely ossify until late teens Glenoid, clavicle, proximal humerus = 17-18 yrs, 16-18 yrs, 18-20 yrs respectively Zaremski J, Krabak B. Shoulder Injuries in the Skeletally Immature Baseball Pitcher and Recommendations for the Prevention of Injury. PM&R. 2012;4(7):509-516.

Relationship between Pitch Type and Injuries Sustained Analyzed pitch type as well Fastball No significant finding Curveball 52% increase in shoulder pain Slider Overall an 86% risk of elbow pain when throwing Specifically 13-14 age group Changeup 12% reduction in risk of elbow pain and a 29% reduction of shoulder pain Over 400 potential pitchers were analyzed (age 9-13) Analyzed fatigue first Found that 75 pitches or more increased odds of shoulder injury 2 fold Not as significant for elbow injury Lyman S, Fleisig G, Andrews J, Osinski E. Effect of Pitch Type, Pitch Count, and Pitching Mechanics on Risk of Elbow and Shoulder Pain in Youth Baseball Pitchers. The American Journal of Sports Medicine. 2002;30(4):463-468.

Other Risk Factors for Injury Focused on trunk rotation of adolescent pitchers compared to mature pitchers Due to lack of hip total rotation Adolescents initiated trunk rotation earlier Hypothesized that this causes anterior instability Increased valgus stress on UCL Glenohumeral internal rotation deficit (GIRD) 10-17° of internal rotation deficit Shown to lead to SLAP and an increase in UCL tears Hibberd et al. 47 high school pitchers 40 (85%) have GIRD Keeley D, Hackett T, Keirns M, Sabick M, Torry M. A Biomechanical Analysis of Youth Pitching Mechanics. Journal of Pediatric Orthopaedics. 2008;28(4):452-459. Hibberd E, Shutt C, Oyama S, Blackburn J, Myers J. Physical contributors to glenohumeral internal rotation deficit in high school baseball players. Journal of Sport and Health Science. 2015;4(3):299-306.

Recommendations to Decrease Risk of Injury Specific Exercises Core strengthening Shoulder Lower Body Balancing exercises Improves KC control Proper education Signs of Fatigue Pitcher’s mechanics General knowledge of the 6 cycles Pitch Count Limiting adolescents to 75 pitches per outing Little League Baseball has begun this Type of Pitch No curveballs or sliders Try to throw low and force ground balls

Specific Exercises Thrower’s Ten Program Kinetic Chain Control Single leg squat with twist Lateral lunge to balance Lower extremity stretching Shoulder Exercises Scapular wall slides I’s, Y’s, T’s Sleeper, Overhead, Crossover Stretch Core Exercises Bird Dogs to crunch Forward & Slide Planks Lumberjacks

Clinical Bottom Line The time is now to teach adolescent pitchers how to properly pitch. The combination of biomechanics, coaching, and exercise needs to be used to keep kids healthy for their entire baseball career. Keep this sport great again

Questions?? THANKS FOR COMING! 

References Oyama S. Baseball pitching kinematics, joint loads, and injury prevention. Journal of Sport and Health Science. 2012;1(2):80-91. Shanley E, Thigpen C. Throwing Injuries in the Adolescent Athlete. The International Journal of Sports Physical Therapy. 2013;8(5):630-640. Ciccotti M, Atanda A, Nazarian L, Dodson C, Holmes L, Cohen S. Stress Sonography of the Ulnar Collateral Ligament of the Elbow in Professional Baseball Pitchers. The American Journal of Sports Medicine. 2014;42(3):544-551. Wolf B, Wolstenholme K. Throwing injuries: biomechanics, injury mechanisms and rehabilitation. Current Orthopaedic Practice. 2010;21(5):467-471. Zaremski J, Krabak B. Shoulder Injuries in the Skeletally Immature Baseball Pitcher and Recommendations for the Prevention of Injury. PM&R. 2012;4(7):509-516. Heyworth B, Kramer D, Martin D, Micheli L, Kocher M, Bae D. Trends in the Presentation, Management, and Outcomes of Little League Shoulder. The American Journal of Sports Medicine. 2016;44(6):1431-1438. Lyman S, Fleisig G, Andrews J, Osinski E. Effect of Pitch Type, Pitch Count, and Pitching Mechanics on Risk of Elbow and Shoulder Pain in Youth Baseball Pitchers. The American Journal of Sports Medicine. 2002;30(4):463-468. Keeley D, Hackett T, Keirns M, Sabick M, Torry M. A Biomechanical Analysis of Youth Pitching Mechanics. Journal of Pediatric Orthopaedics. 2008;28(4):452-459. Hibberd E, Shutt C, Oyama S, Blackburn J, Myers J. Physical contributors to glenohumeral internal rotation deficit in high school baseball players. Journal of Sport and Health Science. 2015;4(3):299-306.