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What makes the ball go-overview of the kinetic

chain in throwing

W. Ben Kibler, MD

Medical director

BODY ASBODY ASA SYSTEM A SYSTEM

HANAVAN MODELHANAVAN MODEL

33

11

22 7766

9988

OF LINKSOF LINKS(SEGMENTS)(SEGMENTS)

Adapted from Hanavan, EP. Mathematical Model Adapted from Hanavan, EP. Mathematical Model of the Human Body. Wrightof the Human Body. Wright--Patterson Air Force Patterson Air Force

Base, Ohio, 1964, AMRLBase, Ohio, 1964, AMRL--TR, 64TR, 64--102.102.

554411111010

13131212

1414 1515

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THE KINETIC CHAIN

Trunk

Shoulder

ElbowWrist

F

O

R

Legs

Trunk and Back

0

C

E

TIMEAdapted From Groppel

Kinetic ChainTransfer of Forces

• Ground – Foot• Up Leg Knee• Hip Hip• Back• Scapula• Arm• Ball/ Racquet

KINETIC CHAIN LINKLINK

CONTRIBUTIONS

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LONGITUDENAL-%

• Hip/trunk-energy 51, force 54

• Shoulder energy 13 force 21• Shoulder-energy 13, force 21

• Elbow-energy 21, force 15

• Wrist-energy 15, force 10• Kibler WB Clin Sports Med 14: 79-86, 1995

CROSS SECTION• Hip/trunk- ball impact- 10%• Shoulder rotation- 54%• Elbow- 10%• Elbow- 10%• Wrist- 26%

• Elliott et al J Appl Biomech 11: 443-447, 1995

ARM FORWARD MOVEMENT

• Thoracoscapular muscle activation- 40%activation 40%

• Rotator cuff- 18% – Happee et al, Journal of Biomechanics, 28:

1179-1191, 1995

• “Core”- 42%

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Arm motion- ball release

Hirashima, M et al Journal of Neurophysiology 97: 680-691, 2007

Hirashima, M et al Journal of Neurophysiology 97: 680-691, 2007

CORRELATION WITH BALL VELOCITY

• Upper extremity strength- .46

• Lower extremity strength- .89

Kraemer et al, Journal of Sport Kraemer et al, Journal of Sport Rehabilitation, 4: 79Rehabilitation, 4: 79--88, 199588, 1995

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Kinetic chain factors• Interactive moments

– Forearm acceleration due to shoulder h-adductionto shoulder h adduction

– Varus acceleration due to shoulder IR

– Proximal weakness: 17% increased distal loads

Interactive Moments• Forces from position/ motion of

adjacent segments

Equation for the proximal segment:JMpp+ ( M i θ + l M i θ + i θ )A JF(aau)+ (rpMpsinθp + lpMasinθp + ramasinθd)App- (rpmpcosθp + lpmacosθp + ramacosθd)App IMp app- (lp

2md + rdlpmjcosØ) θp IMp app- rdlpmasinØθp

2 IMp app- (rdlpmdcosØ + lcd + rd

2md) θd IMp app+ rdlpmdsinØ θd

2 IMp app- (rpmpcosθp + lpmdcosθp + rdmdcosθd)g IMpg= (lcp + rp

2mp) θ = lppθp= Net moment on proximal segment

Putnam CA. J Biomech 26:125-135, 1993

JF(as)

JF(aau)

JMsJF(as)

JF(aau)

Biomechanics/pitching• Positions – leading with

hips, hands on top, high elbow at stride foot contact, closed shoulder, stride foot towards home plate

• Observation, video• Davis et al AJSM 37(8): 1484-1491, 2009

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Push throughPush through

Pull throughPull through

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WHAT HAPPENS WHEN THE BALL DOESN’T GO IN DYSFUNCTION

KINETIC CHAIN BREAKAGE

• Injury- proximal• Inflexibility- local

(GIRD) distant hip(GIRD), distant- hip• Muscle weakness/

imbalance• Poor mechanics-

local, distant

RESULTS FROM BREAKAGE

• Decreased energy, force to terminal links

• Altered performance• Altered performance-velocity, location

• “Catch up” in distal links to maintain performance

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“CATCH UP”• Increased energy, force need to be

developed in distal links

– Increased mass velocityIncreased mass, velocity, acceleration

• Smaller muscle cross section

• Less time- ball release, impact

“CATCH UP”

344.433.3SHLDR VEL

%Catch UpNormal

Trunk

Shoulder

Elbow

Wrist

F

O

R

8016.259SHLDR

MASS

VEL

20% DECREASE IN TRUNK K.E.

Legs

Trunk and Back

0

R

C

E

TIMEAdapted From Groppel

Results Small vs. Large Knee Flexion

Large Knee Small Knee

Number of players 14 6

Knee Flex @ MER (º)* 16 ± 4 6 ± 3

Ball velocity (m/s) 45 ± 6 45 ± 7

**Significant difference (p<0.05)

** Sign. diff., even when normalized

Ball velocity (m/s) 45 ± 6 45 ± 7

Max. IR Torque (Nm)** 56 ± 18 64 ± 12

Max. Varus Torque (Nm)** 63 ± 14 74 ± 15

Fleisig GS, et.al.Fleisig GS, et.al.

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IMPLICATIONS FOR CLINICALCLINICAL

EVALUATION

IMPLICATIONS

• Body works/fails as a unit

• Alterations in performance parameters may be firstparameters may be first indicators of problems in kinetic chain function

• Weak/tight/imbalanced

IMPLICATIONS

• Visual evaluation

– On field, in office

Vid l ti• Video evaluation

• Dynamic motion

– Baseball positions

– Tennis nodes

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IMPLICATIONS

• In injury, alterations exist and must be evaluated in physical examphysical exam

– Hip/trunk strength

– Back flexibility

– Scapular position/motion

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THE KINETIC CHAIN

Shoulder

ElbowWrist

F

O

R

Legs

Trunk and Back

0

R

C

E

TIMEAdapted From Groppel

Shoulder rotation, flexibility, strength

Internal derangement

Scapular dyskinesis

Leg stability series

Hip rotation

Plank

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CONCLUSIONS• Kinetic chain exam as part

of comprehensive evaluation – observation, video analysis office examvideo analysis, office exam

• Technique modifications• Rehabilitation of entire

kinetic chain, base to scapula to shoulder

THANK YOU