9/13/2013
What makes the ball gooverview of the kinetic
chain in throwing
W. Ben Kibler, MD
Medical director
HANAVAN MODEL
1
BODY AS
A SYSTEM
OF LINKS
(SEGMENTS)
2
6
7
3
8
9
4
10
11
5
12 13
14
15
Adapted from Hanavan, EP. Mathematical Model
of the Human Body. WrightWright-Patterson Air Force
Base, Ohio, 1964, AMRLAMRL-TR, 64
64--102.
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THE KINETIC CHAIN
Wrist
Elbow
F
O
Shoulder
R
Trunk
and Back
C
E
Legs
0
TIME
Adapted From Groppel
Kinetic Chain
•
•
•
•
•
•
•
Transfer of Forces
Ground – Foot
Up Leg  Knee
 Hip
 Back
 Scapula
 Arm
 Ball/ Racquet
KINETIC CHAIN
LINK
CONTRIBUTIONS
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LONGITUDENAL-%
• Hip/trunk-energy 51, force
54
• Shoulder-energy
Shoulder energy 13
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%
• Wrist- 26%
• Elliott et al J Appl Biomech 11: 443-447, 1995
ARM FORWARD
MOVEMENT
• Thoracoscapular muscle
activation- 40%
activation
• 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
Rehabilitation, 4: 7979-88, 1995
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Kinetic chain factors
• Interactive moments
– Forearm acceleration due
to shoulder h-adduction
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
+ (r
( pMpsinθ
i θp + lpMasinθ
i θp + ramasinθ
i θd)App
- (rpmpcosθp + lpmacosθp + ramacosθd)App
- (lp2md + rdlpmjcosØ) θp
- rdlpmasinØθp2
- (rdlpmdcosØ + lcd + rd2md) θd
+ rdlpmdsinØ θd2
- (rpmpcosθp + lpmdcosθp + rdmdcosθd)g
= (lcp + rp2mp) θ = lppθp
= Net moment on proximal segment
JF(aau)
IMp app
IMp app
IMp app
IMp app
IMp app
IMpg
JF(as)
JF(aau)
JF(as)
JMs
Putnam CA. J Biomech 26:125-135, 1993
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 through
Pull through
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WHAT HAPPENS
WHEN THE BALL
DOESN’T GO IN
DYSFUNCTION
KINETIC CHAIN
BREAKAGE
• Injury- proximal
• Inflexibility- local
(GIRD) distant(GIRD),
distant hip
• Muscle weakness/
imbalance
• Poor mechanicslocal, distant
RESULTS FROM
BREAKAGE
• Decreased energy,
force to terminal links
• Altered performance
performancevelocity, 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
mass, velocity
velocity,
acceleration
• Smaller muscle cross section
• Less time- ball release, impact
“CATCH UP”
Wrist
Normal
Catch Up
Elbow
F
%
O
SHLDR
VEL
3.3
SHLDR
MASS
9
4.43
16.25
34
Shoulder
R
Trunk
and Back
C
80
E
Legs
20% DECREASE IN TRUNK K.E.
0
TIME
Adapted 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
Max. IR Torque (Nm)**
56 ± 18
64 ± 12
Max. Varus Torque (Nm)**
63 ± 14
74 ± 15
*Significant difference (p<0.05)
Fleisig GS, et.al.
** Sign. diff., even when normalized
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IMPLICATIONS FOR
CLINICAL
EVALUATION
IMPLICATIONS
• Body works/fails as a unit
• Alterations in performance
parameters may be first
indicators of problems in
kinetic chain function
• Weak/tight/imbalanced
IMPLICATIONS
• Visual evaluation
– On field, in office
• Video
Vid evaluation
l ti
• Dynamic motion
– Baseball positions
– Tennis nodes
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IMPLICATIONS
• In injury, alterations exist
and must be evaluated in
physical exam
– Hip/trunk strength
– Back flexibility
– Scapular position/motion
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THE KINETIC CHAIN
F
Wrist
Elbow
O
Shoulder
R
Trunk
and Back
C
E
Legs
0
TIME
Adapted 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
analysis, office exam
• Technique modifications
• Rehabilitation of entire
kinetic chain, base to
scapula to shoulder
THANK YOU
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