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

(°)

Stride Ext Rot@ FC Elbow @ FC Knee @ FC Max Elbow Max Hor Add Max Ext Rot Elbow @ Rel Hor Add @ Rel Trunk @ Rel Knee @ Rel Hor. Add Youth 85 67 74 43 95 21 177 24 11 32 36 910 174 23 10 31 43 890 HS Coll 85 64 82 50 100 20 85 55 85 48 99 20 173 23 9 33 39 820 175 23 9 33 38 830 Pro 86 58 87 46 98 17

Sh Anterior Elb Proximal Sh Proximal Sh Posterior

Results - Force (Newtons)

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 Significant relationship between forces at shoulder & elbow joints for pitching mechanics variables when adjusted for physical differences.

Pro 44 103 121 44

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

• Anterior Band of UCL (main valgus stabilizer) attaches to the medial epicondyle apophysis

Elbow - Anatomy/Mechanics

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 U S A 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 U S A 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 9-10 Game Workload Limit in Pitches Week Season 50 11-12 75 13-14 75 75 100 125 1000 1000 1000 Year 1000 3000 3000

American Baseball Foundation Thank you

ABF BASIC Program at Rickwood Field