1. Overuse Throwing Injuries in Adolescent Athletes and Pitch Counts: Is The Answer Right In Front of Us?
Southeast-ACSM Regional Meeting ǀ Chattanooga, TN ǀ February 17th, 2018
Jason L. Zaremski, MD, CAQSM, FAAPMR, FACSM
Assistant Professor
Divisions of PM&R, Sports Medicine, and Research
Co-Medical Director High School Outreach Program
Department of Orthopaedics and Rehabilitation
University of Florida

2. Thank You
Dr. Matthew Close
Dr. Ken Barnes
SE-ACSM

3. Disclosure
Neither I, Jason L Zaremski, nor any family member(s), have any relevant financial relationships to be discussed, directly or indirectly, referred to or illustrated with or without recognition within the presentation.

4. Learning Objectives Why Injuries Happen Epidemiology Fatigue’s Effects
Preventing Overuse Throwing Injuries with Pitch Restrictions: What Does the Research Say?

5. When Does The Injury Cycle Start?
Youth
Pre-HS HS
College
Pro/MLB

6. Why do we get injured?
Windt J, Gabbett TJ. How do training and competition workloads relate to injury? The workload-injury aetiology model. Br J Sports Med Mar;51(5): doi: /bjsports

7. Why do we get injured? Skeletally Immature Overuse, Poor Biomechanics
Pitching In Pain
Windt J, Gabbett TJ. How do training and competition workloads relate to injury? The workload-injury aetiology model. Br J Sports Med Mar;51(5): doi: /bjsports

8. LOTS of Overuse Throwing Injuries
Not Quite Accurate…Though Sure Seems Like It

9. HS Injury Epidemiology
Shoulder injury rate 1.39/10,000 Athlete-Exposures (AEs)
Elbow injury rate of 0.86/10,000 AEs
Injuries sustained by pitchers:
Shoulder (39.6%)
Elbow (56.9%)
Between 40-57% injuries were chronic and caused by overuse
Saper MG, et al. Epidemiology of Shoulder and Elbow Injuries Among United States High School Baseball Players: School Years Through Am J Sports Med. October 2017:

10. Contributing Factors to Shoulder & Elbow Injuries
Fatigue
Specific to pitching
Specialization
Pitching more games, months, and pitches per year
Lifting weights during the season
innings and pitches per game
Playing year round
warm-up pitches before a game
Playing in > 1 league at the same time
Players who were more frequently started as pitchers
Increased age + weight
Limited GIRD
Preseason supraspinatus weakness
High pitch velocity
Throwing breaking pitches (curveballs and sliders) maybe
Participation in showcases
Saper, et al. AJSM Epidemiology of Shoulder and Elbow Injuries Among United States High School Baseball Players: School Years Through

11. Which Factors Can Result from Fatigue?
Specific to pitching
Specialization
Pitching more games, months, and pitches per year
Lifting weights during the season
innings and pitches per game
Playing year round
warm-up pitches before a game
Playing in > 1 league at the same time
Players who were more frequently started as pitchers
Increased age + weight
Limited GIRD
Preseason supraspinatus weakness
High pitch velocity
Throwing breaking pitches (curveballs and sliders) maybe
Participation in showcases
Saper, et al. AJSM Epidemiology of Shoulder and Elbow Injuries Among United States High School Baseball Players: School Years Through

12. Let’s Talk about Fatigue
“It is important for each league to set workload limits for their pitchers to limit the likelihood of pitching with fatigue. Research has shown that pitch counts are the most accurate and effective means of doing so.”
But what is the actual workload?

13. Components of Fatigue? Volume
Pitch Counts (daily)
Cumulative Fatigue (Oliver 2017, Erickson 2016, Grantham 2014)
Fatigue and risk of Injury (Olsen, et al 2006)
High pitch velocity (>85mph) associated with increased risk of pitching injury
Greatest associations with pitching injury due to overuse and fatigue.
Poor Biomechanics and Weak Links in the Kinetic Chain (too many references!)
Chu SK, Jayabalan P, Kibler WB, Press J. The Kinetic Chain Revisited: New Concepts on Throwing Mechanics and Injury. PM R. 2016;8(3 Suppl):S69-77.
Kibler, et al. Clin Sports Med 2013.
Kibler, et al. The disabled throwing shoulder: spectrum of pathology-10-year update. Arthroscopy 2013.
Intensity
Velocity (Chalmers et al, 2015)
See next slides
Heart Rate (Cornell et al, 2017)

14. Muscular Fatigue Effects
Studies have indicated that repeated pitching of any kind results in:
Decrease grip strength (Laudner, et al. 2017)
Forearm fatigue (a risk factor for UCL injury (Wang, et al 2016)
Changes in pitching mechanics later in games
when total volume of pitches thrown grows resulting in potential increase risk factors for injury (Pei-Hsi, et al 2015).
Lack of pre-season pitching programs leading to more pitching injuries. (Moore, et al 2013)

15. Timing of Injuries: MLB
Posner, et al. AJSM Epidemiology of Major League Baseball Injuries

16. Timing of Injuries: HS
Injury rates = highest in the first month of the season, particularly in the shoulder
Athletes may benefit from a more gradual increase in activity and a structured off-season injury prevention program.
Shanley E, Rauh MJ, Michener LA, Ellenbecker TS. Incidence of Injuries in High School Softball and Baseball Players. J Athl Train Nov-Dec; 46(6): 648–654.

17. Acute to Chronic Workload
Acute WL = What an athlete has performed in a week…aka athlete’s fatigue level
Chronic WL = What an athlete has performed over 4 weeks…aka state of fitness
Can help to build trends in predicting injury risk
Hulin BT, Gabbett TJ, Blanch P, Chapman P, Bailey D, Orchard JW. Spikes in acute workload are associated with increased injury risk in elite cricket fast bowlers. Br J Sports Med. 2014;48(8):

18. Acute to Chronic Workload Concept
1. Pre-Season Bullpens = How Many Pitches?
2. How Many Live Game Pitches in first few starts?
3. How Many Total Pitches in first few starts?
T.J. Gabbett. The training-injury prevention paradox: should athletes be training smarter and harder? Br J Sports Med, 50 (5) (2016), pp

19. HS Pitchers and # Pitches/Game?
Approximately 70 pitches per start on average (McHugh, et al AJSM 2016)

20. Volume of Pitches—Are We Missing Something?

21. Association between Overhead Throwing Workload and Injury?
First Published Study
159 days of throwing
18 male HS baseball players (4 non-pitchers, 14 pitchers) (aged 17.0 ±0.7 years)
171,703 throws captured
10 injuries
5 out of 6 throwing---related injuries occurred when athletes had an A:C Workload Valgus Ratio > 1.3
Wore sensor based sleeve during pre-season training & entire 2017 regular season
Sleeves were worn daily during practice & games
I won’t name the sleeve but happy to mention after my talk
Mehta, S. Investigating the relationship between workload and throwing injury in elite, baseball athletes. Physical Therapy in Sport. November 2017 Volume 28, Pages e3–e4.

22. Acute to Chronic Workload Concept
T.J. Gabbett. The training-injury prevention paradox: should athletes be training smarter and harder? Br J Sports Med, 50 (5) (2016), pp

23. Number “Gameday” Pitches
1 Game = Live Game + BP + Warm-Ups HS Top 3 starters = about 10 starts in a season (12 weeks) Travel Ball = 8-12 weeks. 1 start a week. 10 more starts. 20 Starts over 6 months PLUS non gameday bullpens. = How Many Pitches?????
Ask numbers? Ask audience to guess

24. Pitch Count Study
#1: HS pitchers exceed recorded pitches by approximately 30-40% when including bullpen sessions and warm-up pitches.
#2: There is a wide variability of bullpen pitches thrown per outing within HS pitchers.
Zaremski et al, Accepted OJSM 2018.

25. Counted all pitches thrown off a mound during varsity HS baseball games
34 different HSs in North Central Florida during the 2017 season.
13,769 total pitches were recorded
115 starting varsity high school pitching outings

26. Total Pitches

27. Total Pitches
42.4% of the pitches = not accounted for in pitch count monitoring.
Cannot account for intensity, stress, muscle fatigue
Zaremski et al, Accepted OJSM 2018.

28. Variability of Bullpen Pitch Volume
There is a large variability of bullpen pitches thrown with 25% of our dataset throwing less than 22 pitches and 25% throwing more than 33 pitches per outing.

29. Let’s Return to # of Pitches per Season
Pitchers were categorized by pitch count for the season
High: >400
Moderate:
Low: <180
1 Game = Live Game + BP + Warm-Ups + Other HS Top 3 starters = about 10 starts in a season (12 weeks) Travel Ball = 8-12 weeks. 1 start a week. 10 more starts. 20 Starts over 6 months PLUS non gameday bullpens. = 120 pitches x 20 starts = 2400 pitches over 6 months off a mound just in games
Ask numbers? Ask audience to guess

30. Which Factors Can Be Accounted for Due to Pitch Counts?
Fatigue
Specific to pitching
Specialization
Pitching more games, months, and pitches per year
Lifting weights during the season
innings and pitches per game
Playing year round
warm-up pitches before a game
Playing in > 1 league at the same time
Players who were more frequently started as pitchers
Increased age + weight
Limited GIRD
Preseason supraspinatus weakness
High pitch velocity
Throwing breaking pitches (curveballs and sliders) maybe
Participation in showcases
Saper, et al. AJSM Epidemiology of Shoulder and Elbow Injuries Among United States High School Baseball Players: School Years Through

31. Recommended Rest Guidelines
Watch and respond to signs of fatigue
No overhead throwing of any kind for at least 2-3 months/year (4 months is preferred)
No competitive baseball pitching for at least 4 months/year
Limits for pitch counts and adhere to days of rest
Avoid pitching on multiple teams and showcases
Good throwing mechanics
MLB Pitch Smart and USA Baseball

32. Prevention Principles
Rest Guidelines
Pre-season Throwing Programs
In-season Conditioning
ROM Assessments
GH (TROM), Elbow, Hips, Spine, DF-Ankles, and Hamstrings

33. Doc, What Throwing Program?
North: HS Pre-Season Feb-March HS Season March/April-June South: HS Pre-Season Dec-Jan HS Season Feb-May North: Travel Ball May/June-Sept South: Travel Ball May-??? North Off-season: Oct-Jan. PRIME TRAINING South Off-season: Say What?

34. Take Home Points
1. Prepare for the season ahead in the offseason 2. Prevention limits injury but does not prevent injury 3. Overuse + Biomechanics + Kinetic Chain Analysis
Three quick to-the-point tips attendees should be able to take away from your presentation that will apply to their practice today

35. Outside the Box Thinking
In-season monitoring improving!
Improve off-season throwing to build up Chronic Workload with a slower buildup in pre-season?
Will training harder in off-season to build up arm strength while still maintaining pitch restriction guidelines in-season to limit overuse be a recipe for success?

36. Selected References
Cornell DJ, et al. In-Game Heart Rate Responses Among Professional Baseball Starting Pitchers. J Strength Cond Res Jan;31(1):24-29
Chalmers PN, et al. Correlates With History of Injury in Youth and Adolescent Pitchers. Arthroscopy Jul;31(7):
Hurd WJ, Kaufman KR. Glenohumeral rotational motion and strength and baseball pitching biomechanics. J Athl Train May-Jun;47(3):
Wilk KE, et al. Deficits in Glenohumeral Passive Range of Motion Increase Risk of Shoulder Injury in Professional Baseball Pitchers: A Prospective Study. Am J Sports Med Oct;43(10):
Saito M, et al. Relationship Between Tightness of the Hip Joint and Elbow Pain in Adolescent Baseball Players. Orthop J Sports Med May 12;2(5):
Tyler TF, et al. Risk Factors for Shoulder and Elbow Injuries in High School Baseball Pitchers: The Role of Preseason Strength and Range of Motion. Am J Sports Med Aug;42(8): doi: /
Oliver GD, et al. Effects of a Simulated Game on Upper Extremity Pitching Mechanics and Muscle Activations Among Various Pitch Types in Youth Baseball Pitchers. J Pediatr Orthop Mar 21.
Erickson BJ, et al. The Impact of Fatigue on Baseball Pitching Mechanics in Adolescent Male Pitchers. Arthroscopy May;32(5): doi: /j.arthro
Grantham WJ, et al. The Impact of Fatigue on the Kinematics of Collegiate Baseball Pitchers. Orthop J Sports Med Jun 9;2(6):
Olsen SJ, et al. Risk factors for shoulder and elbow injuries in adolescent baseball pitchers. Am J Sports Med Jun;34(6):

37. Additional References
American Sports Medicine Institute Youth UCL Surgery data. Accessed November 16th, 2015.
Azar FM, Andrews JR, Wilk KE, Groh D. Operative treatment of ulnar collateral ligament injuries of the elbow in athletes. Am J Sports Med. 2000;28(1):16-23.
Cain EL Jr., Andrews JR, Dugas JR, et al . Outcome of ulnar collateral ligament reconstruction of the elbow in 1281 athletes: results in 743 athletes with minimum 2-year follow-up. Am J Sports Med. 2010;38:2426–2434.
Conte SA, Hodgins JL, ElAttrache NS, Patterson-Flynn N, Ahmad CS. Media perceptions of Tommy John surgery. Phys Sportsmed Aug 26:1-6.
Conte SA, Fleisig GS, Dines JS, Wilk KE, Aune KT, Patterson-Flynn N, ElAttrache N. Prevalence of Ulnar Collateral Ligament Surgery in Professional Baseball Players. Am J Sports Med Jul;43(7):
Dines JS, Yocum LA, Frank JB, ElAttrache NS, Gambardella RA, Jobe FW. Revision surgery for failed elbow medial collateral ligament reconstruction. Am J Sports Med Jun;36(6):
Dines JS, Frank JB, Akerman M, Yocum LA. Glenohumeral internal rotation deficits in baseball players with ulnar collateral ligament insufficiency. Am J Sports Med Mar;37(3):
Accessed November 15th, 2015.
Erickson BJ, et al. Trends in Medial Ulnar Collateral Ligament Reconstruction in the United States: A Retrospective Review of a Large Private-Payer Database From 2007 to Am J Sports Med Jul;43(7):
Erickson BJ, Gupta AK, Harris JD, et al. Rate of return to pitching and performance after Tommy John surgery in Major League Baseball pitchers. Am J Sports Med. 2014;42(3):

38. Additional References
Fleisig GS, Andrews JR. Prevention of elbow injuries in youth baseball pitchers. Sports Health Sep;4(5):
Fleisig GS, Andrews JR, Dillman CJ, et al. Kinetics of baseball pitching with implications about injury mechanisms. Am J Sports Med. 1995;23(2): 233–9.
Hurd WJ, Jazayeri R, Mohr K, Limpisvasti O, Elattrache NS, Kaufman KR. Pitch velocity is a predictor of medial elbow distraction forces in the uninjured high school-aged baseball pitcher. Sports Health Sep;4(5):415-8.
Jones KJ, Conte S, Patterson N, ElAttrache NS, Dines JS. Functional outcomes following revision ulnar collateral ligament reconstruction in Major League Baseball pitchers. J Shoulder Elbow Surg May;22(5):642-6.
Kerut EK, Kerut DG, Fleisig GS, Andrews JR. Prevention of arm injury in youth baseball pitchers. J La State Med Soc Mar-Apr;160(2):95-8.
Olsen SJ II, Fleisig GS, Dun S, et al. Risk factors for shoulder and elbow injuries in adolescent baseball pitchers. Am. J. Sports Med. 2006; 34: 905–12.
Marshall NE, Keller RA, Lynch JR, Bey MJ, Moutzouros V. Pitching performance and longevity after revision ulnar collateral ligament reconstruction in Major League Baseball pitchers. Am J Sports Med May;43(5):  
MLB Pitchsmart--
Parks ED, Ray TR. Prevention of overuse injuries in young baseball pitchers. Sports Health Nov;1(6):514-7.
Petty DH, Andrews JR, Fleisig GS, Cain EL. Ulnar collateral ligament reconstruction in high school baseball players: clinical results and injury risk factors. Am J Sports Med. 2004;32(5):
 Vitale MA, Ahmad CS. The outcome of elbow ulnar collateral ligament reconstruction in overhead athletes: a systematic review. Am J Sports Med Jun;36(6):
Wilk KE, et al. Deficits in glenohumeral passive range of motion increase risk of elbow injury in professional baseball pitchers: a prospective study. Am J Sports Med Sep;42(9):
 Wilson AT, Pidgeon TS, Morrell NT, DaSilva MF. Trends in Revision Elbow Ulnar Collateral Ligament Reconstruction in Professional Baseball Pitchers. J Hand Surg Am Nov;40(11):
Zaremski JL, Krabak BJ. Shoulder injuries in the skeletally immature baseball pitcher and recommendations for the prevention of injury. PMR Jul;4(7):
Zaremski JL, Horodyski MB, Donlan RM, Tang S, Farmer KW. Does Climate Matter? A Comparison of Ulnar Collateral Ligament Reconstruction in Collegiate Baseball Pitchers in a Northern versus Southern Conference. Orthopaedic Journal of Sports Medicine. November 2015 vol. 3 no. 11. doi: /

39. Thank you
Questions?
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