Arm Injuries Among Baseball Pitchers and the
Kinetic Chain Link
Dr. Andrew Robb BA, DC, CSCS, ART®, D. Acu, FRCCSS(C)
Dr. Robb
Chiropractic Sports Specialist
Clinical Faculty - CMCC
Certified Strength and Conditioning
Specialist
NCCP Level 1 Baseball Coach
Baseball Consultant
• Laurier, Waterloo, Kitchener Minor
Baseball, Team Ontario Fastball
Journal Peer Reviewer: Sport
Health, J Chiro Medicine, JMPT,
Am. Journal Sports Med.
Agenda For Today
1.
2.
3.
4.
Arm Injuries in Baseball
Clinical Context for the manual practitioner
Exploration of the Kinetic Chain Link
Concluding Remarks
Multi-factoral
Epidemiological confirmations
Biomechanical consideration (associations)
How does a pitcher progress to imaging
confirmed pathology to surgical
candidate?
Robb, Fleisig, Cooper, Brody, Seaver
The Physics of a Phenom: The Strasburg Machine
July 2, 2010
#1
The “Arm Problem”
4X
Risk
Pitch Count
>5
inn/str
>8mo
5x Risk
Innings
Length of
Season
FATIGUE = 36x likely
Olsen et al 2004
Throwing 101
Putnam et al 1993, Fleisig et al 1995, Kibler et al 2013
50-60% force
from LEGS
60% of speed
from CORE
Reduction of
function in the
lower extremity
by 20% increases
shoulder
function by 34%
<40% overall
from SHOULDER
REGIONAL INTERDEPENDENCE
“…the concept that seemingly unrelated impairments in a remote anatomical region may contribute to, or be
associated with, the primary complaint or focus of performance.” Wainner et al 2007
Factors considered to alter arm problems: poor balance, altered coordination from the lower to upper
extremity, limited function of the lower extremity, repetitive overuse, unilateral movement
The “DYSFUNCTIONAL” Kinetic Link
CLINICAL PEARL #1
The shoulder is a conduit for speed
transmission when the core
converts FORCE from the lower
extremity (SPEED PRINCIPLE)
(Burkhart et al 2003, Putnam 1991)
Rushed motion
Leg drive simultaneous with
pelvis rotation
Upright trunk at ball release
Lack balance
Reduction in leg drive (20%) increases shoulder
loading 34%
Less stride length
Hannon et al 2014, Garrison et al 2013, Davis et al 2009
The “DYSFUNCTIONAL” Kinetic Link
Reduced pelvic rotation
Lack lead hip IR
Increase stress on shoulder
Lower Ball velocity
Robb et al 2010, Laudner et al 2014
The “DYSFUNCTIONAL” Kinetic Link
Late pelvic-hip rotation
Excessive trunk rotation speed
Poor pelvic-trunk dissociation
EXCESSIVE SHOULDER WORK
(<40 degrees)
Reduced ball velocity
Wright et al 2001, Oyama et al 2014, Fleisig et al 1996
The “DYSFUNCTIONAL” Kinetic Link
CLINICAL PEARL #2
Maximal External Rotation (MER)
of shoulder a function of:
1. Trunk rotation and sequencing
2. Horizontal adduction
(Fleisig et al 1996)
Assess trunk rotation and
pectoralis stregth
Reduced INTERNAL
ROTATION of shoulder &
fatigue
INCREASED JOINT STRESS TO
THE MEDIAL ELBOW (UCL!!)
Dines et al 2009
The “DYSFUNCTIONAL” Kinetic Link
Upright trunk position at
cocking and ball release
Reduced ER and lower
adduction of shoulder
Reduced ball velocity
Davis et al 2009, Oyama et al 2014
The “DYSFUNCTIONAL” Kinetic Link
Rushed motion
Trunk dysfunction
Poor leg drive
Reduced hip motion
Lack balance
Less stride length
EXCESSIVE
SHOULDER WORK
Coordination/control
Compliance (flexibility/strength)
FATIGUE
BIOMECHANICAL
FAULTS
Poor Performance/Injury
Shoulder GIRD assoc. with UCL
laxity
Repetitive throwing assoc. with
posterior capsule changes
resulting in GIRD
CLINICAL PEARL #3
To optimize the speed principle
coordination and sequencing of
body segments during throwing is
necessary.
Increased shoulder ER
associated with increased valgus
loading
Increased or early trunk rotation
assoc with increased shoulder
stress
The pelvics should rotate BEFORE
the trunk!
Increased trunk rotation speed
increases shoulder ER
Lack of pelvic rotation increases
trunk rotation speed and onset
Lack of hip ROM assoc with
increased shoulder torque
Lack of hip ROM assoc. reduced
pelvic rotation
Thanks to baseball rebellion.com
“Better information = better decisions = better performance”
Frank Spaniol 2009 NSCA
Although the biomechanical
literature demonstrates
ASSOCIATIVE factors, no
cause-effect can be
definitive. Prudence to
investigate the entire chain
among throwing is critical.
Thank-you