Injury Prevention Related to Pitching
E. David Osinski M.A.
Glenn S. Fleisig, Ph.D.
Biomechanics of Pitching
• Adult pitchers (college & pro)
– ASMI 18 studies published in last ten years
– All levels (youth thru pro)
– Kinematic (angular displacements and velocities)
and kinetic (forces & torques) comparison of
baseball pitching among various levels of
development. (Fleisig et al, J Biomechanics, 1999)
Results - Position (°)
Youth
Stride
85
Ext Rot@ FC
67
Elbow @ FC
74
Knee @ FC
43
Max Elbow
95
Max Hor Add
21
Max Ext Rot
177
Elbow @ Rel
24
Hor Add @ Rel
11
Trunk @ Rel
32
Knee @ Rel
36
Hor. Add
910
HS Coll
85
85
64
55
82
85
50
48
100
99
20
20
174 173
23
23
10
9
31
33
43
39
890 820
Pro
86
58
87
46
98
17
175
23
9
33
38
830
Results - Force (Newtons)
Sh Anterior
Elb Proximal
Sh Proximal
Sh Posterior
Youth
210
400
480
160
HS
290
630
750
280
Coll
350
770
910
350
Pro
390
910
1070
390
Significant relationship between kinetic forces at
shoulder & elbow joints for variables for pitching
mechanics for youth through professional pitchers.
Results - Force (%Weight)
Sh Anterior
Elb Proximal
Sh Proximal
Sh Posterior
Youth
39
74
89
30
HS
39
85
101
38
Coll
44
96
113
44
Pro
44
103
121
44
Significant relationship between forces at shoulder &
elbow joints for pitching mechanics variables when
adjusted for physical differences.
Wind Up Commencement Movements
High School
Foot Contact
Pelvis = 25° open
Upper Torso
= 20° closed
Shoulder:
Abduction = 90°
Rotation = 65°
Elbow:
Flexion = 80°
Stride
High School
Max. Rotation
Shoulder:
Rotation = 175°
Elbow:
Flexion = 100°
Arm Cocking
High School
Shoulder:
Anterior Force=290N
IR Torque = 51 Nm
Elbow:
Varus Torque=48Nm
(Weight = 740 N =
170 lb)
Arm Cocking
High School
Arm Acceleration
Elbow:
Extension = 2200°/s
Shoulder:
Rotation = 6800°/s
Arm Acceleration
High School
Shoulder:
Proximal Force =
750 N
Elbow:
Proximal Force =
630 N
(Weight = 740 N =
170 lb)
Arm Acceleration
Deceleration & Follow-Through
Pathomechanics
PHYSEAL INJURY
Little Leaguer’s Shoulder
• First by Dotter described in 1953
• Described in literature as
– osteochondrosis of the proximal humeral epiphysis
– proximal humeral epiphyseolysis
– stress fracture of proximal humeral epiphyseal
plate
– rotational stress fracture
Adolescent Pitcher Shoulder Injury
• Typically males, 12 - 15 years of age
• 14 y/o more prone due to rapid growth and more
skilled
• Average duration of symptoms before treatment is
approximately 7 months
• Associated with quantity and intensity of pitching, age
at which pitching started, use of curveball
PHYSEAL INJURY
Little Leaguer’s Shoulder
Elbow - Anatomy/Mechanics
• Anterior
Band of
UCL (main
valgus
stabilizer)
attaches to
the medial
epicondyle
apophysis
Elbow - Anatomy/Mechanics
• Increased bone
plasticity
• Hyperelasticity
permits excessive
joint translation
Elbow Injuries
Skeletally immature athletes are
susceptible to unique injuries
secondary to:
• Relatively weak growth plates (physes)
• Ligamentous laxity
• Inadequate dynamic strength / stability
to resist high biomechanical forces
Medial Epicondyle
Apophysitis / Avulsion
• Most common injury
seen in the adolescent
throwing athlete
• Caused by acute valgus
overload
• X-rays may appear
normal
1996 Survey
(USA Baseball News, 1996)
• Survey for USA Baseball
• 28 Orthop. Surgeons & Baseball Coaches
• number of pitches more important than innings
• Increase pitch count limits with age
Examples: 8-10: 50 pitches. 17-18: 90 pitches
• Start using pitches at different ages
– Fastball (8), Change (10), Curve (14), Slider (16)
1997-98 Study
(Med Sci Sport Exerc, 2001)
• 200 pitchers each Spring (300 total subjects)
• 8-12 years old pitchers in Birmingham
• 50% of pitchers had elbow/shoulder pain during
study
• Increased pitches  Increased pain risk
– 75 pitches/game recommended limit
– 600 pitches/season recommended limit
1999 Study
(Am J Sports Med, 2002)
• Funded by USA Baseball
• 500 pitchers in Spring
• 9-14 years old pitchers throughout Alabama
• Increased pitches  Increased pain risk
– 75 pitches/game recommended limit (15 batters)
– 600 pitches/season recommended limit (120 batters)
• No relation found between mechanics - pain risk
• Curveballs/Sliders  Increased pain risk
Conclusions - Mechanics
• Successful youth and adult pitchers use similar
kinematics.
• Relationship between poor mechanics and risk of
injury unproven
Conclusions - Pitch Quantity
• Correlation between pitch count and pain in
youth pitchers
• College/Pros use pitch counts to protect
pitchers. Youth pitchers should do as well.
Conclusions - Pitch Quantity
USA Baseball Medical Committee
Recommendations 2003
Age
Workload Limit in Pitches
Game
Week
Season
9-10 50
75
1000
11-12 75
100
1000
13-14 75
125
1000
Year
1000
3000
3000
American Baseball Foundation Thank you
ABF BASIC Program at Rickwood Field