THROWING BIOMECHANICS MADE EASY

1. BIOMECHANICS OF
THROWING
KAVITA JOSHI
(MPT 2ND YR)

2. Drive From The Large Leg Muscles
Rotation Of The Hips
Segmental Rotation Of The Trunk & Shoulder Girdle.

3. "Whip Like" Transfer Of Momentum
Elbow Extension & Small Muscles Of Forearm, Hand
Propulsive Force
Ball

4.  PHASES
4 Phases
• PREPARATION / WIND-UP
• COCKING
• ACCELERATION - 2% Time Sequence
• DECELERATION/ FOLLOW-THROUGH - 18% time sequence
80% Time
Sequence

5. IN BASEBALL PITCH
COCKING PHASE
Early Cocking ( Stride Phase)
Late Cocking

6. A) WIND UP PHASE
 Quietest Phase Of The Activity
 The Thrower Prepares To Perform The Throw
 Entire body - Most Inactive State
 2 Body Positions
 Foot Positions
 Stride Stance- Rapid Release Of Ball

7. KINEMATICS
- TRANSFER OF BODY WEIGHT
- WINDING UP
- FLEXION OF HIP & KNEE- 90°
- BACK FLEXES TO PRODUCE WINDING UP OF THE BODY

8. KINETICS
FORCE ABSORPTION-BW: Hip Abd, Add, & Extensors
TRUNK: Back Extensors (Ecc.)
FRONT LEG: Hip Flexors (Con.), Knee Extensors (Ecc.)
SHOULDER: Anterior Deltoid, Pectoralis Major
SCAPULA: Upper Trap, Serratus Anterior, Lower Trap

9. B) COCKING
 Enables Body Segments To Contribute To Ball Propulsion
 SHOULDER: Horizontal Extensn - Abd.- Max. ER
 SCAPULA: Max Retractn. , TRUNK: Lateral Lean
Max. ER
Shoulder "Loaded"
Anterior Capsule Tighten ( Ant. Restraints)
Apprehension Position
Storing Elastic Energy Subtle Instability
OVERUSEE

10. NOTE:
 Lateral Trunk Flexion + ROTATION = Degree Of Arm Abduction
 Overhand Athlete Leans Contralaterally
 Side-arm / Submarine Thrower Leans Toward The Throwing Arm

11. B) ACCELERATION
Begins After Max ER Of Shoulder
Ends With Release Of The Ball
Lasts: 1/20 Of a Second
TRUNK & PELVIS When Rotation Stops
Greatest Rotation Speed Arm Unwinds
Provides A Thrust
Propels UE Forward

12. KINEMATICS
• Scapula: Protracts
• GH jt : MR
• Elbow: 90° of flexn to 120° flexn
• Forearm: Pronation
• Wrist : Extensn To Neutral
• Pivot Leg : Hip Extensn, Knee Flexn, Ankle PF

13. KINETICS
• GH Jt: Subscapularis , Pect. major
• SCAPULA: Serratus Ant.
• ELBOW: Triceps
• WRIST & FOREARM: FCR, FCU, Pronators

14. B) DECCELERATION
• Period From The Release Of Ball To End Of All Motion
• FIRST PART: Shoulder MR
• SECOND PART: Arm Adducted Across Body
 Shoulder Continues To Adduct
Compensates For Less Trunk Rotatn, Scapular Motion

15. KINETICS
- All Muscles Are Acting Eccentrically For Decleration
 SHOULDER: Horizontal Flexors (Add.), MR
 ELBOW: Flexors
 FOREARM: Pronators
 TRUNK: Eccentric To Concentric
 Rest Of The Body “Catches Up” With The Arm
Forward Progression Of The Pivot Leg (Hip Flexors)

16. SCAPULAR BIOMECHANICS
IN THROWING

17. Normal ST Rhythm Allows The Scapula
To Rotate Upwardly During Abduction,
Bringing The Glenoid Fossa Directly
Under The Humeral Head To Lend
Stability To The Glenohumeral Joint

18. SCAPULA FUNCTIONS
1. Provides A Stable Socket For Humerus
2. Retracts & Protracts Along The Thorax
3. Rotates To Elevate The Acromion
4. Provides A Base For Muscle Attachment
5. Provides A Key Link In The Kinetic Chain

19. ABNORMAL
BIOMECHANICS

22. CONSEQUENCES DUE TO ABNORMAL
PHYSIOLOGY

23.  Lack Of Full Retraction
Thorax Destabilizes Cocking Point
Prevents Acceleration
 Lack Of Full Protraction
Increases The Deceleration
Alters Safe Zone Glenoid Humerus
(Acceleration Phase)
 Too Much Protraction
Tightness In GH Capsule
Impingement
Changes In Safe Zone Of GH Angle

24.  Lack Of Acromial Elevation
Impingement (Cocking & follow Through)
Inhibit Function- Serratus Ant, Lower Trap
 If The Scapula Is Unstable
The Lack Of An Anchor
-Affects The Function - Scapular Muscles
-Muscles ≠ Torque - Muscular Imbalance
-Doesn’t Give Stable Base For GH Rotation
-Arm Loses Mechanical Efficiency
-Other Risks: Spinal Accessory Nerve Palsies
Loss Of Coordinated Retractn/Protractn
Opens Up The Front Of GH Jt.
Insufficient Anterior Bony Buttress
Anterior Translation Of Humeral Head
Se Shear Stress - Anterior Stabilizers
Se Stability Of Glenoid - ROTATING HUMERUS

25. LOSS OF THE LINK FUNCTION OF THE
KINETIC CHAIN
SCAPULAR DYSFUNCTION
Impairs Force Transmission From Lower To
UE
Reduces Force Delivered To Hand
Creates A Situation Of "Catch-up"
MORE DISTAL LINKS OVERWORK TO
COMPENSATE FOR THE LOSS OF
PROXIMALLY GENERATED FORCE

26. THIS EXPLAINS INJURIES UNRELATED TO UE CAN AFFECT UPPER LIMB
THROWING MECHANICS AND PREDISPOSE TO FURTHER, OR MORE
SERIOUS, UE INJURY.
Decreased Push-off Due To Achilles Tendinopathy
Decreased Quadriceps Drive After A Muscle Strain
Decreased Segmental Trunk Rotation Secondary To Thoracic Segmental
Hypomobility

27. CHANGES IN THROWING ARM WITH
REPEATED PITCHING

28. AT SHOULDER
Increased Range Of External Rotation
Repeated Stress To The Anterior Capsule (Cocking Phase)
Stretch Or Breakdown In The Anterior Static Stabilizers
Compromise Dynamic Balance: Shoulder Function Stability
Anterior Instability & Secondary Impingement

29. STRENGTH RATIO OF IR / ER
 The Normal Ratio- 3:2
 In Throwers:
- Imbalance Is Exaggerated Over Time
- Lack Of ER Strength Increase Vulnerability To Injury
Highlight The Need For A Structured Exercise Program

30. Structural Changes At The Elbow
Due To Valgus Stress Applied In The Throwing Action
Breakdown Of The Medial Stabilizing Structures (MCL, Jt Cap., Flexor ms)
Development Of Increased Carrying Angle
Less Frequently- The Eccentric Overload Causes :
 Anterior Capsular Strains
 Posterior Impingement
 Forearm Flexor Strains
 Fixed Flexion deformity.

31. COMMON BIOMECHANICAL
ABNORMALITIES SPECIFIC TO PITCHING

32. 1) “OPENING UP TOO SOON”
2) “HANGING”
3) “BREAKING”

33. REFERENCES
• PEGGY HOUGLAM- CLNICAL KINESIOLOGY
• KARIM KHAN