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Pathomechanics Pathomechanics ofof
Common Shoulder InjuriesCommon Shoulder Injuries
Kevin E. Kevin E. WilkWilk, DPT, DPT
Birmingham,Birmingham,
Alabama, USAAlabama, USA
www.www.kevinwilkkevinwilk. com. com
Shoulder Injuries in SportsShoulder Injuries in SportsIntroductionIntroduction
•• Shoulder injuries are common in sportsShoulder injuries are common in sports
»» Collision sports Collision sports –– football, wrestling, skiing football, wrestling, skiing……
•• College football College football –– 4 4thth most common injured most common injured
jointjoint
Kaplan et al: AJSM Kaplan et al: AJSM ’’0505
•• Professional Football NFL CombineProfessional Football NFL Combine
–– 55thth AC joint sprains AC joint sprains
–– 99thth GH joint instability GH joint instability
•• BrophyBrophy et et al:Medal:Med SciSci Sports Sports ‘‘0707
»» Contact sports Contact sports –– soccer, basketball, soccer, basketball,
•• Shoulder injuries occur in various sportsShoulder injuries occur in various sports
Collision Sports Contact SportsCollision Sports Contact Sports
Shoulder Injuries in SportsShoulder Injuries in SportsContact SportsContact Sports
Shoulder Injuries in SportsShoulder Injuries in SportsContact SportsContact Sports
Bankart Bankart LesionLesion
Detachment of Detachment of capsulolabralcapsulolabral complex complex
increases translation by nearly 200%increases translation by nearly 200%
Lazarus: JBJS Lazarus: JBJS ‘‘9696
The Overhead ThrowerThe Overhead ThrowerIntroductionIntroduction
•• Shoulder & elbow injuries are common inShoulder & elbow injuries are common inbaseballbaseball
•• In professional baseballIn professional baseball
•• 28 % of all injuries occur to the shoulder joint28 % of all injuries occur to the shoulder joint
•• 22 % of all injuries occur to elbow joint22 % of all injuries occur to elbow joint
•• Length of injury time is increasing Length of injury time is increasing –– days on days onthe disabled list daysthe disabled list days
Conte et al: Am J Conte et al: Am J Spts Spts Med Med ’’0101
•• In youth baseball In youth baseball –– 50 % of players (9-14) 50 % of players (9-14)complained of elbow or complained of elbow or shldr shldr painpain Lyman et al: Am J Lyman et al: Am J Spts Spts Med Med ’’0202
•• Number of injuries increasing & ageNumber of injuries increasing & agedecreasing decreasing –– UCL injuries UCL injuries
Petty, Andrews, Petty, Andrews, FleisigFleisig: AJSM : AJSM ‘‘0404
The Overhead ThrowerThe Overhead ThrowerIntroductionIntroduction
Biomechanics of the Biomechanics of the
Shoulder Joint Complex Shoulder Joint Complex
During ThrowingDuring Throwing
The ThrowerThe Thrower’’s Shoulders Shoulder
Fine line: Fine line:
Too loose & just right !!! Too loose & just right !!!
•• Excessive MotionExcessive Motion
especially External Rotationespecially External Rotation
•• Requires stabilityRequires stability
•• Inherent hyper-laxityInherent hyper-laxity
•• Allows tremendous mobilityAllows tremendous mobility
Paradox of the ThrowerParadox of the Thrower’’s Shoulders Shoulder
““Loose enough to throw, butLoose enough to throw, but
stable enough to preventstable enough to prevent
symptomssymptoms””
Wilk: AJSM Wilk: AJSM ‘‘0202
Biomechanics Laboratory Set-UpBiomechanics Laboratory Set-Up
•• 85 x 30 x 15 ft. Indoor Laboratory85 x 30 x 15 ft. Indoor Laboratory
•• Motion Analysis System Motion Analysis System (Motion Analysis Corp.)(Motion Analysis Corp.)
Biomechanics Laboratory EquipmentBiomechanics Laboratory Equipment
• 8 high-speed cameras (240 Hz)
• Automatic 3D digitizing
• Reflective markers
Pitching Biomechanics : ProcessPitching Biomechanics : Process
• Marker Placement
• 21 total (4 on hat)Acromion
Lateral Epicondyle
Greater Trochanter
Distal Ulna
Distal Radius(only on pitching hand)
Distal 3rd Metacarpal(only on pitching hand)
2 in. Superior to Proximal Fibula
Lateral Malleolus
Distal 3rd Metatarsal
•• High-Speed Video (Vision Research Inc.)High-Speed Video (Vision Research Inc.)
»» 450 frames/second450 frames/second
Biomechanics Laboratory EquipmentBiomechanics Laboratory Equipment
• Written Report
• High-Speed Video
• Unlimited Support
Pitching Biomechanics : Process
Scientific Feedback
Pitching Biomechanics : Introduction
•• Kinetic ChainKinetic Chain
»» Coordinated activation of body segmentsCoordinated activation of body segments
Six Phases Six Phases
Pitching BiomechanicsPitching Biomechanics : Phases of Pitching : Phases of Pitching
1. Wind-Up
2. Stride
3. Arm Cocking
4. Arm Acceleration
5. Arm Deceleration
6. Follow-Through
Pitching BiomechanicsPitching Biomechanics : :Phases of PitchingPhases of Pitching
WindupWindup
Low force/torque on
shoulder & elbow
StrideStride
Foot Contact
Shoulder:
Abduction = 90°
Ext. Rotation = 60°
Stride Length & Knee Angle
0 in
Stride Direction
Lead Leg Position @ Stride Foot ContactLead Leg Position @ Stride Foot Contact
Pitching Biomechanics : Stride Foot ContactPitching Biomechanics : Stride Foot Contact
12 in 5 in
% Height
36 °51 °
Shoulder Abduction
Upper Arm Position @ Stride Foot ContactUpper Arm Position @ Stride Foot Contact
Pitching Biomechanics : Stride Foot ContactPitching Biomechanics : Stride Foot Contact
90°
Shoulder External Rotation
38 °
75 °
81°
103°
Upper Arm Position @ Stride Foot Contact Upper Arm Position @ Stride Foot Contact
Pitching Biomechanics : Stride Foot ContactPitching Biomechanics : Stride Foot Contact
Elbow FlexionShoulder Horizontal Abduction
34 °14 ° 75 ° 104 °
Arm Cocking Arm Cocking
Pitching Biomechanics : Phases of PitchingPitching Biomechanics : Phases of Pitching
From Stride Foot Contact to Maximum Shoulder External Rotation
•• Trunk Rotation: Stride Foot Contact to MERTrunk Rotation: Stride Foot Contact to MER
Pitching Biomechanics : Arm CockingPitching Biomechanics : Arm Cocking
Pelvis
•Max. Velocity = 518 – 675°/sec
Upper Trunk
•Max. Velocity = 1,077 – 1,229 °/sec
•19 - 39% after FC
•40 - 56% after FC
•• Upper Arm Position @ MERUpper Arm Position @ MER
Pitching Biomechanics : MERPitching Biomechanics : MER
Maximum External RotationMaximum Elbow Flexion
11
4°
91° 189 °
174 °
Arm CockingArm Cocking
Body rotates forward
as the arm rotates
backwards
Maximum External
Rotation = 145>
Arm AccelerationArm Acceleration
Internal Rotation
Velocity = 7500°/s
Arm AccelerationArm Acceleration
How fast is 7500°/s ?
Fastest measured human
joint motion
If the arm maintained
that peak speed for 1
second, it would make
about 20 full revolutions!
Pitching Biomechanics : Arm AccelerationPitching Biomechanics : Arm Acceleration
•Max. Extension Velocity
•2,224– 2,684 °/sec
Elbow Shoulder
•Max. Internal Rotation Velocity
•6,688 – 8,352 °/sec
•• Upper & Lower Body Position @ Ball ReleaseUpper & Lower Body Position @ Ball Release
Pitching Biomechanics : Ball ReleasePitching Biomechanics : Ball Release
Shoulder Abduction &
Lateral Trunk TiltHip Flexion & Knee Angle
14 ° 31 °
102 °
86 °
46 ° 23 °
108°
89 °
Arm DecelerationArm Deceleration
Large deceleration
forces on shoulder
Maximum Internal
Rotation = 0°
Follow-ThroughFollow-Through
Shoulder resists and
controls horizontal
adduction
Large body parts
dissipate energy from
arm
Balance is necessary
for fielding position
PathomechanicsPathomechanics
Two critical instantsTwo critical instants
Max. ER Ball Release
•• ShoulderShoulder
»» Abduction = 90 Abduction = 90 ºº
»» Ext Rotation = 180 Ext Rotation = 180 ºº
»» Anterior Force = 400 NAnterior Force = 400 N
»» Int Int Rot Torque = 67 NmRot Torque = 67 Nm
(equivalent to 40 lbs. (equivalent to 40 lbs.pulling down on thepulling down on thehand)hand)
• Shoulder
– Abduction = 90 º
– Ext Rotation = 180 º
– Anterior Force = 400 N
– Int Rot Torque = 67 Nm
• Shoulder
– Abduction = 90 º
– Ext Rotation = 180 º
– Anterior Force = 400 N
PathomechanicsPathomechanics
Max. ER
40
• Shoulder
– Abduction = 90 º
– Ext Rotation = 180 º
•• FaultsFaults
Biomechanical Evaluations: ExamplesBiomechanical Evaluations: Examples
Foot Contact Pelvis RotationFoot Contact Ball Release
Internal ImpingementInternal ImpingementWhat is it ?What is it ?
!! Occurs during abduction & excessiveOccurs during abduction & excessiveexternal rotationexternal rotation
!! Late cocking during pitchingLate cocking during pitching
!! Supraspinatus Supraspinatus / / Infraspinatus Infraspinatus rubs onrubs onthe the posterosuperior glenoid posterosuperior glenoid rim &rim &labrumlabrum
!! Results in fraying of cuff and Results in fraying of cuff and glenoidglenoidlabrum labrum –– inflammation inflammation
Andrews: Tech OrthopAndrews: Tech Orthop’’8888
WalchWalch: JSES : JSES ‘‘9191
Andrews, Andrews, WilkWilk, Reed et al: , Reed et al: Sprg TrnSprg Trn
‘‘0000•• 31 31 asymptomaticasymptomatic professional baseball professional baseball
pitchers in spring trainingpitchers in spring training
•• MRI of MRI of glenohumeralglenohumeral joint joint
•• 28/31 (90 %) abnormal 28/31 (90 %) abnormal glenoidglenoid labrum labrum
•• 27/31 (87 %) abnormal rotator cuff27/31 (87 %) abnormal rotator cuff
appearanceappearance
•• 12/31 (39%) humeral head changes12/31 (39%) humeral head changes
•• All pitchers were pain-free at time ofAll pitchers were pain-free at time of
studystudy
JostJost, , ZumsteinZumstein, Gerber: CORR , Gerber: CORR ‘‘0505
•• 30 competitive 30 competitive SwissSwiss handball players handball players
•• MRI performed both shouldersMRI performed both shoulders
•• 93% throwing abnormal MRI - but only 37%93% throwing abnormal MRI - but only 37%
were symptomaticwere symptomatic
•• Partial rotator cuff tears most commonPartial rotator cuff tears most common
•• SuperolateralSuperolateral osteochondralosteochondral of humeral head of humeral head
defects presentdefects present
•• Evaluation critical to diagnosis Evaluation critical to diagnosis –– not just MRI not just MRI
External Rotation External Rotation "" Performance Performance
102 ± 2 %102 ± 2 %104 ± 2 %104 ± 2 %Time Shoulder Time Shoulder VelVel
91 ± 2 %91 ± 2 %93 ± 2 %93 ± 2 %Time Elbow Time Elbow VelVel
37 ± 7 37 ± 7 °°29 ± 11 29 ± 11 °°Forward TrunkForward Trunk
179 ± 8 179 ± 8 °°166 ± 9 166 ± 9 °°External RotationExternal Rotation
High VelocityHigh VelocityLow VelocityLow Velocity
The Shoulder Joint in TennisThe Shoulder Joint in Tennis
Shoulder Injuries in TennisShoulder Injuries in TennisGoals of PresentationsGoals of Presentations
•• Physical characteristics of tennis playersPhysical characteristics of tennis players
•• Discuss some research in tennisDiscuss some research in tennis
•• Discuss specific injuries & RxDiscuss specific injuries & Rx
»» ImpingementImpingement
»» Scapular dysfunctionScapular dysfunction
»» Biceps painBiceps pain
The ServeThe Serve
KINEMATIC VARIABLESKINEMATIC VARIABLES
•• GH ABD:GH ABD: 9393°° 96 ° 96 ° 83 ° 83 °
•• MAX GH ER:MAX GH ER: 173 173 °° 164 164 °° 154 °154 °
•• GH IRGH IR 7550 7550 °/s°/s 4950 °/s4950 °/s 1514 °/s1514 °/s
•• ELB FLXN ELB FLXN 22 22 °° 36 36 °° 35 35 °°
•• ELBOW EXT:ELBOW EXT: 2340 2340 °/s°/s 1760 °/s1760 °/s 1700 °/s1700 °/s
FLEISIG ET AL, FLEISIG ET AL, ‘‘96, SHAPIRO & STINE, 96, SHAPIRO & STINE, ‘‘9292
Comparison Baseball Throwing toComparison Baseball Throwing to
Tennis Serve KinematicsTennis Serve Kinematics Joint KinematicsJoint Kinematics
Tennis Serve: Tennis Serve:
!! 83 deg abduction83 deg abduction
!! 1,074-2,300 deg/sec1,074-2,300 deg/sec
!! ER to 154 degreesER to 154 degrees
Shapiro: Shapiro: Unpub Unpub ‘‘9292
DillmanDillman:: USTA USTA ‘‘9191
Baseball Throwing:Baseball Throwing:
!! 90-100 deg abduction90-100 deg abduction
!! 7250 deg/sec 7250 deg/sec accelaccel..
!! 0.5 x BW late cocking0.5 x BW late cocking
!! ER to 175 deg.ER to 175 deg.
!! 75-100% BW 75-100% BW deceldecel phase phase
!! Late cocking Late cocking ––ball 0.03secball 0.03sec
Fleisig:AJSMFleisig:AJSM’’9595
Wilk: Wilk: SptsSpts Med Med ArthroArthro ‘‘0000
The ForehandThe Forehand
The BackhandThe Backhand
Injuries in TennisInjuries in TennisIntroductionIntroduction
•• Repetitive overuse UE injuries:Repetitive overuse UE injuries:
»» TendinitisTendinitis
»» Muscle strainsMuscle strains
»» SLAP lesionsSLAP lesions
»» TendonosisTendonosis
»» EpicondylitisEpicondylitis
»» Stress fracturesStress fractures
Overuse TraumaOveruse Trauma
Injuries in TennisInjuries in TennisUpper Extremity InjuriesUpper Extremity Injuries
•• Shoulder injuries:Shoulder injuries:
»» ImpingementsImpingements’’
•• Internal impingementInternal impingement
•• SubacromialSubacromial impingement impingement
»» GlenoidGlenoid labrum labrum
•• SLAP lesionsSLAP lesions
»» TendinitisTendinitis
»» TendonosisTendonosis
»» Partial thickness tearsPartial thickness tears
•• PASTA lesionsPASTA lesions
•• PAINT lesionsPAINT lesions
The Biomechanics of theThe Biomechanics of the
Golf SwingGolf Swing
Maximum Velocity During SwingMaximum Velocity During Swing(Degrees Per Second)(Degrees Per Second)
PGAPGA LPGALPGA
Hip turnHip turn 451 451 536 536
Shoulder turnShoulder turn 713 713 692 692
Arm velocityArm velocity 1151 1151 1082 1082
Club velocityClub velocity 2102 2102 1688 1688
THE GOLF SWINGTHE GOLF SWING
•• Set-up positionSet-up position
•• Backswing phaseBackswing phase
•• Downswing phaseDownswing phase
»» Forward swingForward swing
»» AccelerationAcceleration
•• Follow-through phaseFollow-through phase
SET-UP POSITIONSET-UP POSITION
•• Important phase of golf swingImportant phase of golf swing
•• Align golfer with targetAlign golfer with target
•• Establish postural balanceEstablish postural balance
»» Knee flexion 20-25Knee flexion 20-2500
»» Wt distribution 50-60% back footWt distribution 50-60% back foot
»» Primary spinal angle (trunk flexion)Primary spinal angle (trunk flexion)
»» Secondary spinal angle (lateral RSecondary spinal angle (lateral Rbend)bend)
IMPROPER SET-UPIMPROPER SET-UP
POSITION POSITION
•• Very common among amateursVery common among amateurs
•• Most common not using hip- hingeMost common not using hip- hinge
positionspositions
»» primary spinal angle formed by spineprimary spinal angle formed by spine
•• Improper grip pressureImproper grip pressure
»» excessive grip pressureexcessive grip pressure
•• Poor postural balancePoor postural balance
BACKSWING PHASEBACKSWING PHASE
•• Purpose of backswing is to positionPurpose of backswing is to position& align the golfer& align the golfer’’s hub of rotations hub of rotationto execute a powerful swingto execute a powerful swing
•• Linear smooth movementLinear smooth movement
•• Trunk rotationTrunk rotation
•• Backswing complete when club isBackswing complete when club isparallel (near) to groundparallel (near) to ground
BACKSWING PHASEBACKSWING PHASE
•• Right shoulder abducts & ERRight shoulder abducts & ER
•• Left shoulder adducts & IRLeft shoulder adducts & IR
•• Scapula (L) protracts, elevatesScapula (L) protracts, elevates& upward rotates& upward rotates
»» Right shoulder ER 90-100Right shoulder ER 90-10000
»» Left shoulder IR 65-70Left shoulder IR 65-7000
•• Proper shoulder turnProper shoulder turn
•• Pelvic rotation of at least 45Pelvic rotation of at least 4500
•• Critical, but unnatural movementCritical, but unnatural movement
IMPROPER BACKSWINGIMPROPER BACKSWING
PHASEPHASE
•• Most common flaw lateralMost common flaw lateral
movements of hips & legsmovements of hips & legs
•• Move laterally instead of rotatingMove laterally instead of rotating
within base of supportwithin base of support
•• Lack of trunk rotation, (poorLack of trunk rotation, (poor
flexibility) shoulder mobilityflexibility) shoulder mobility»» Lead shoulder: limited adduction & IRLead shoulder: limited adduction & IR
»» Back shoulder: limited ER (flying elbow!!!!)Back shoulder: limited ER (flying elbow!!!!)
THE DOWNSWINGTHE DOWNSWING
PHASEPHASE•• Forward swing and accelerationForward swing and acceleration
•• Initiated by hip turn & wt. transferInitiated by hip turn & wt. transfer
•• Centrifugal force & angular momentum toCentrifugal force & angular momentum togenerate clubhead speedgenerate clubhead speed
•• Clubhead speed: 2581Clubhead speed: 258100/sec (100 mph)/sec (100 mph)
•• Pelvic rotation speed: 498Pelvic rotation speed: 49800/sec/sec
•• Arm speed: 1165Arm speed: 116500/sec/sec
•• Move laterally instead of rotating withinMove laterally instead of rotating withinbase of supportbase of support
•• Lack of trunk rotation, (inflexibility):Lack of trunk rotation, (inflexibility):greater shoulder mobilitygreater shoulder mobility
THE DOWNSWINGTHE DOWNSWING
PHASEPHASE
•• Impact occurs for 0.0005 sec.Impact occurs for 0.0005 sec.
»» Highest incidence of injuries(50%)Highest incidence of injuries(50%)
•• Highest muscle activity:Highest muscle activity:
»» Right side: pectoralis major,Right side: pectoralis major,subscapularis, latissimus dorsisubscapularis, latissimus dorsi
»» Left side: latissimus dorsi &Left side: latissimus dorsi &subscapularissubscapularis, posterior muscles, posterior muscles
IMPROPER DOWNSWINGIMPROPER DOWNSWING
PHASEPHASE
•• Loss of swing path due to weightLoss of swing path due to weight
shiftingshifting
»» Lost swing in backswingLost swing in backswing
•• Amateurs generate 50-80% greaterAmateurs generate 50-80% greater
spine forces & 50% greater EMGspine forces & 50% greater EMG
•• Yet professionals generate 34%Yet professionals generate 34%
greater clubhead speedgreater clubhead speed
THE FOLLOW-THROUGHTHE FOLLOW-THROUGH
PHASEPHASE•• Body gradually decelerates rotary movementBody gradually decelerates rotary movement
through eccentric contractionsthrough eccentric contractions
•• Shoulder function as backswing (reverse)Shoulder function as backswing (reverse)
»» Left shldr: abd, horiz abd, ERLeft shldr: abd, horiz abd, ER
»» Right shldr: horiz add, IRRight shldr: horiz add, IR
•• Arms reach shoulder level elbows flexArms reach shoulder level elbows flex
•• Subscapularis, pect major, & latsSubscapularis, pect major, & lats
•• Second highest incidence of injuries (30%)Second highest incidence of injuries (30%)
PHYSICAL FACTORS THATPHYSICAL FACTORS THAT
CAN LIMIT SWINGCAN LIMIT SWING
•• ShouldersShoulders - tightness which limits shoulder turn, - tightness which limits shoulder turn,inability to maintain swing planeinability to maintain swing plane
»» Lead shoulder: limited Lead shoulder: limited HorzHorz add, IR add, IR
then ER @ 55 deg then ER @ 55 deg abdabd
»» Back shoulder: limited ER at 45 deg abductionBack shoulder: limited ER at 45 deg abduction
then then horizhoriz add with IR add with IR
•• Low back - tightness which limitsLow back - tightness which limitsproper set-up, limits rotationproper set-up, limits rotation
•• Hip/pelvis - weakness & tightness limitsHip/pelvis - weakness & tightness limitsrotation, posture swing planerotation, posture swing plane
PHYSICAL FACTORS THATPHYSICAL FACTORS THAT
CAN LIMIT SWINGCAN LIMIT SWING
EvaluationEvaluation
•• ROM & flexibilityROM & flexibility
•• Strength testStrength test
•• Golf functional testGolf functional test
Will your body allow you to Will your body allow you to
swing properly & effectivelyswing properly & effectively
Treat Kinetic ChainTreat Kinetic Chain The Females Throwing ShoulderThe Females Throwing Shoulder
Windmill Softball PitchWindmill Softball PitchBarrentine, et al JOSPTBarrentine, et al JOSPT
4 4 Phases of PitchPhases of Pitch
##WindupWindup
##StrideStride
##DeliveryDelivery
##Follow throughFollow through
Windmill Softball PitchWindmill Softball PitchBiomechanical AnalysisBiomechanical Analysis
•• Wind-up phaseWind-up phase
»» Arm in hyperextensionArm in hyperextension
»» Foot push-offsFoot push-offs
»» Initiate forwardInitiate forward
translation of bodytranslation of body
Windmill Softball PitchWindmill Softball PitchBiomechanical AnalysisBiomechanical Analysis
•• Stride phaseStride phase
»» Emphasis on forwardEmphasis on forward
translation of bodytranslation of body
»» Excessive shoulderExcessive shoulder
flexion (180flexion (18000))
»» Linear velocity ofLinear velocity of
hipships
Windmill Softball PitchWindmill Softball PitchBiomechanical AnalysisBiomechanical Analysis
•• Delivery phaseDelivery phase
»» Trunk rotation 430Trunk rotation 430deg/secdeg/sec
»» Torso rotation 650Torso rotation 650deg/secdeg/sec
»» Arm flexion & IR 5,000Arm flexion & IR 5,000deg/secdeg/sec
##**Shoulder flex 3x BWShoulder flex 3x BW
##**Superior forces 98%Superior forces 98%BWBW
Windmill Softball PitchWindmill Softball PitchBiomechanical AnalysisBiomechanical Analysis
•• Follow through phaseFollow through phase
»» Gradually dissipateGradually dissipate
forcesforces
»» Max shoulder postMax shoulder post
force 59% BWforce 59% BW
»» Elbow compressionElbow compression
force 56% BWforce 56% BW
Windmill Softball PitchWindmill Softball PitchEMG Analysis EMG Analysis –– MaffetMaffet: AJSM : AJSM ‘‘9797
•• From 6 to 3 oFrom 6 to 3 o’’clockclock
»» Infraspinatus 93%Infraspinatus 93%
MVICMVIC
»» Supraspinatus 78%Supraspinatus 78%
MVICMVIC
»» Ant. Deltoid 38%Ant. Deltoid 38%
MVICMVIC
Windmill Softball PitchWindmill Softball PitchEMG Analysis EMG Analysis –– MaffetMaffet: AJSM : AJSM ‘‘9797
•• From 3 to 12 oFrom 3 to 12 o’’clockclock
»» Posterior deltoid 102%Posterior deltoid 102%
»» Teres minor 87%Teres minor 87%
»» Infraspinatus 87%Infraspinatus 87%
Windmill Softball PitchWindmill Softball PitchEMG Analysis EMG Analysis –– MaffetMaffet: AJSM : AJSM ‘‘9797
•• From 12 to 9 oFrom 12 to 9 o’’clockclock
»» Subscapularis 81%Subscapularis 81%
»» Pectoralis major 575Pectoralis major 575
»» Posterior deltoid 52%Posterior deltoid 52%
Windmill Softball PitchWindmill Softball PitchEMG Analysis EMG Analysis –– MaffetMaffet: AJSM : AJSM ‘‘9797
•• From 9 oFrom 9 o’’clock to ballclock to ball
releaserelease
»» Pect major 76%Pect major 76%
»» Subscapularis 75%Subscapularis 75%
»» Serratus anterior 61%Serratus anterior 61%
Shoulder Injuries in SportsShoulder Injuries in SportsConclusionsConclusions
•• Shoulder injuries are common inShoulder injuries are common insportssports
•• Numerous types of lesionsNumerous types of lesions
•• Understanding the Understanding the pathomechanicspathomechanicsassists in diagnosis & treatmentassists in diagnosis & treatment
•• Also may assist in preventionAlso may assist in preventionprogramsprograms
•• Recognition is key to properRecognition is key to propertreatmenttreatment
DankeDanke