update from baseball academia: what's new in baseball medical research
TRANSCRIPT
Update from Baseball Academia: What’s New in Baseball Medical Research
Aaron Gray, M.D. (@MizzouSportsDoc)
Assistant Professor, Departments of Family Medicine & Orthopaedics
University of Missouri
Overview
• Youth Baseball Specialization
• Hamstring Injuries
• Concussions
• Tommy John (Ulnar Collateral Ligament) Injuries
• Inverted W
Patterns of Specialization in Professional Baseball Players• Ginsburg et al. Journal of Clinical Sport Psychology
2014.
– Surveyed 708 minor league baseball players
• 20% Spanish speaking not from North America
• Mean age of sports specialization 15.52 years
– 52% didn’t specialize until at least age 17
Age of Specialization by EthnicitySurvey
RespondentsAge began playing baseball
Age specialized in baseball
% who specialized after age 16
Total Sample n=708 6.2 15.5 64%White American 438 (63%) 5.3 16.5 75%
African American 34 (5%) 10.5 17.2 79%
Asian 10 (1%) 8.9 10.9 0%Hispanic non-American 140 (20%) 6.1 12.7 39%
Hispanic American 44 (6%) 6.1 14.1 43%
Other 27 (4%) 6.6 14.5 42%
Climate Effects on Specialization in Professional Baseball Players• 59% of North American players came from “warm
climate” conducive to year-round practice
– Warm climate specialized earlier (15.8)
– Cool climate (17.6)
• Analysis was done that determined “ethnicity and climate were both related to specialization age, irrespective to the other”
Major League Baseball Injury Surveillance System• 2010 - MLB, players union, and minor league affiliates
reached agreement on creating a electronic medical records system and injury tracking system
– Ability to track traded players
• 2011 - first year of 100% involvement of all MLB and MiLB teams
– MiLB ~245 clubs and ~7500 players
– MLB 30 clubs and ~1200 players
Major League Baseball Injury Surveillance System• MLB Health and Injury Tracking System (HITS)
– Centralized database with de-identified medical data from MLB Electronic Medical Record (EMR)
Hamstring Injuries
• Studies in multiple sports show re-injury risk of 12-31%
• 2011 – Players with hamstring injuries collected $30 million while disabled
Major and Minor League Baseball Hamstring Injuries• Christopher Ahmad et al. AJSM, 2014.
• Epidemiological Findings from the Major League Baseball Injury Surveillance System
• Only recorded time loss hamstring injuries occurring in a game (spring training, regular season or post season)
Athlete Exposure
• 1 athlete involved in a practice or game = 1 athlete exposure
– Basically, every player in the box score
• Example of National League game
• 9 players start game + 2 relief pitchers + 2 pinch hitters = 13 athlete exposures
• Limitations
2011 Major and Minor League Baseball Time Loss Injuries
Major League Minor League TotalAvg # of players per game 14 13 13
# of athlete exposures (AE) 69,076 302,744 366,886
# of players injured 541 2558 3099
Total game injuries 871 3697 4568
Injury rate (per 1000 AE 12.5 12.0 12.1
Time Loss Injuries by Body Part and Injury Type
Injury Diagnosis Major LeagueNumber
Major League
Percentage
Minor League Number
Minor League
PercentageHamstring Strain 50 5.7 218 5.9Adductor Strain 36 4.1 85 2.3Oblique Muscle Strain 36 4.1 88 2.4Hand Contusion 32 3.7 203 5.5Leg Contusion 26 3.0 124 3.4Concussion 18 2.1 101 2.7
Hamstring Injuries
• In 2011 - MLB & MiLB: Hamstring injury rate 0.7 per 1000 AE
• ~1 hamstring injury per 100 games per team
Hamstring Strains by ActivityMLB # MLB % MiLB # MiLB %
Base running 31 62 154 70.6
Fielding 10 20 29 13.3
Unknown 4 8 8 3.7
Pitching 2 4 14 6.4
Other 1 2 2 0.9
Catching 1 2 3 1.4
Hitting 1 2 6 2.8
Majority of base running injuries were running to first and majority of those were right handed.
Time-Loss to Hamstring Injuries
1-3 days 4-7 days 8-15 days 16-30 days >30 days0
5
10
15
20
25
30
35
12
22
30
10
26
5
21
2725
23
MLB % MiLB %
Per
cent
age
of H
amst
ring
Inju
ries
Average time-lossMLB - 24 daysMiLB - 27 days
Recurrent Hamstring Injuries
• Only reported if player had an injury in 2010 and 2011
• 20% of major league injuries were recurrent
• 8% of minor league injuries recurrent
• Much greater recurrence rates than oblique or adductor groin strains
Recurrent Hamstring, Oblique and Groin Injuries
Major League Minor LeagueTotal in 2010 Recurrent in
2011Total in 2010 Recurrent in
2011Hamstring 50 10 375 18
Oblique 44 0 148 4
Groin 34 2 100 1
Hamstring Injury Seasonal Timing
April May June July August September0
20
40
60
80
100
120
140
160
Injury Rate (1 Hamstring Injury Every n Games)
MLB MiLB Avg Temp
Tem
p D
egre
es o
r Num
ber o
f Gam
es
Hamstring Injury Prevention
Hamstring Injury Prevention
• Soccer Hamstring Injury Rates
– Recurrence rate of 22% within first 2 months
– 25% recur the following season
• Petersen et al. AJSM 2011
– ~1000 professional & amateur soccer teams randomized to 10 week eccentric training program followed by weekly seasonal program
Nordic Hamstring Exercise
Nordic Hamstring Exercise Protocol
Results
Overall Initial Recurrent
3.8 3.17.1
13.18.1
45.8
Hamstring Injuries per 100 Player Seasons
Intervention Control
MLB Hamstring Prevention Pilot Program
• Some Minor and Major League teams started using the Nordic Hamstring Curl preventative exercises
– 25% reduction in hamstring injuries in MLB
– Decreased days lost to 14.25 days from 24 days previously
Concussions
• Gary Green et al. AJSM 2015.
• Mild Traumatic Brain Injury in Major and Minor League Baseball Players
Concussions
• 2010 Pilot Data was collected
– 50% of concussions got better in 7 days or less
• This data led to the 7 day concussion disabled list
• Data for this study from 2011-2012
Concussions
• Injury rates were only calculated for regular season and are per 1000 Athlete Exposures
Total MLB MiLBConcussions 307 266 41
Regular Season 277 241 36
Used to calculate time loss
207 170 31
Injury Rate 0.42 0.46 0.26
Excluded from Time Loss Calculation
• Injuries occurred less than 30 days from end of season and they did not return
• Injured toward end of spring training with more than a week until regular season game
• If they participated in short season
• Season ending injury
Time Loss Results from Concussion
• Majors
– TL HITS: Mean 11, median 8 (range 0-51)
– TL Medical Director: Mean 11, median 9 (range 1-44)
– TL Box Score: Mean 13, median 9 (range 0-60)
Activity During Concussion
Fielding Batting Running Other0
10
20
30
40
50
60
53.4
27.4
9 10.1
51.2
19.5
14.6 14.6
Minors Majors
Fielding Concussions by Position
Pitcher Catcher Infield Outfield
14.8
40.8
26.1
18.3
9.5
47.6
28.6
14.3
Percentage of Concussions by Position
Minors Majors
Catchers
• 7.4% of all non-concussive injuries but 40% of MLB concussions!
Major League Minor LeaguesPlayer Collision 4 (40%) 24 (41%)
Contact w/ batted ball 6 (60%) 18 (31%)
Contact w/ non-pitched ball 0 5 (9%)
Contact w/ pitched ball 0 0
Contact w/ bat 0 9 (3%)
Pitchers
• 23 concussions by pitchers
– 15 hit with batted ball and 2 in MLB
• ~750,000 pitches per year in MLB and on avg 1-2 pitchers hit in head each year
Bryan Mitchell
Tommy John Injuries
• Prevalence of Ulnar Collateral Ligament Surgery in Professional Baseball Players
• Conte et al. AJSM, 2015.
• Online survey administered by certified athletic trainers for each MLB team to all MLB and MiLB players
Tommy John Injuries
• 5088 players responded
– Pitchers 53% of respondents
• 10% of players reported previous Tommy John surgery
– 16% of pitchers
– 3% of non-pitchers
Tommy John Injuries
• Major League Pitchers
– 25% had a history of Tommy John surgery
– 86% had TJ surgery as a professional
• Minor League Pitchers
– 15% had history of Tommy John surgery
– 61% had TJ surgery during high school or college
• No difference in prevalence in pitchers born in United States vs Latin America
The Inverted W: Good or Bad?
Early Cocking Phase Mechanics and Upper Extremity Surgery Risk in Starting Professional Baseball Pitchers
• Douoguih et al. Orthopedic Journal of Sports Medicine, 2015.
• 250 starters during 2010 season included in study
• Video for each pitcher was reviewed for Inverted W and early trunk rotation
• Identified shoulder or elbow surgery from beginning of career to end of 2010
• Inverted W – defined as elevated of 1 or both elbows above the shoulder in early cocking phase of throwing motion
Early Trunk Rotation – trunk rotation before stride foot hits the ground and occurrence of non vertical trunk rotation at initiation of trunk rotation
Results
• 2 investigators achieved consensus on inverted-W in 88% of players and early trunk rotation in 86% of players
Rate of Surgery, n/Total (%)
Position With Position Without Position
Inverted-W 28/93 (30%) 42/155 (27%)
Early trunk rotation 37/111 (33%) 30/132 (23%)
Future Directions
Return from injury studies using pitch tracking, batted ball tracking, and defensive player tracking
