The Effects of a Posture
Compressive Shirt onRotator Cuff Muscle Strength

K. C. Owsley, M.D.
Brian Neri, M.D.
Karen Mohr, PT
Neal ElAttrache, M.D.

Shoulder Function
 The shoulder does not function in isolation
 Shoulder/Scapula is a link in a kinetic chain

 Any break in the chain affects the energy,

force and velocity that is generated

Scapular Function

Static shoulder model

Dynamic shoulder modelScapular Position

Scapular Protraction
Internal rotation
Anterior tilt
Superior translation

Serratus anterior
Pectoralis minor
Levator scapulae
Pectoralis major

 Associated with multiple deleterious shoulder effects
 Related to an inability to properly achieve retraction

Scapular Protraction– Narrow subacromial space w/ impingement– Increased IGHL strain– GH “hyperangulation” – internal RTC impingement– Superior glenoid labrum injuries– Decreased muscle strength

Scapular Retraction
External rotation
Posterior tilt
Inferior translation

Trapezius (middle/lower fibers)
Rhomboids
Latissimus dorsi

 Mechanically favored position for maximal shoulder function.
McClure, et al JSES 2001
Ludewig, et al JPOT 2000
Kibler, et al AJSM 2006

Scapular Positioning Scapular braces can effectively optimize scapular

position at rest and with motion.
–Uhl et al, ASES 2005

 A Scapular brace system has been shown to increase

IR/ER strength in asymptomatic subjects–Smith et al , KJOC-AOSSM 2007

Is it scapular position or muscle compression?

Compression Garments
 Medical grade– Lymphedema, burn recovery, post surgical, DVT

prophylaxis.
improve peripheral circulation and venous return improve clearance of blood lactate and markers of muscle
damage such as creatine kinase reduce muscle oscillation

Compression GarmentsCompression Garments•Enhances power based activities
 Sports
basedgear•Improvecirculation/clearance of blood lactate /CK•Reduce muscle oscillation– UnderArmour(>$250 mil/yr)•Augmented proprioception•Enhancedor
mechanics– FashionscienceCompression GarmentsVolleyball players and max height of jump… NO, but increased theability to resist fatigue.
–Varsity track athletes loose vs compressive shorts. Inc jump height/ decmuscle oscillation w/ landing–Int J Sports Med 2006

“Supersuits” of power lifters did increase strength but were poorly tolerated–

J Sport Con Res 1996

Am J Physical Med 1987

Commercial compression suits did not increase resistance/fatigue on
effected muscles but did decrease injury potential
J Sport Con Res 1998
Sports Med 1997
Eur J Appl Physiol 1998
Br J Spts Med 2006
J Sports Rehab 2001
J Orthop Spts Phys Ther 2001

Hypothesis
Application of a form fitting, compressive scapular
positioning shirt would result in improvements indemonstrated rotator cuff strength compared witha compression shirts or wearing no shirt.

Posture Shirt®
backPosture Shirt®
front

Under Armour®

Methods Investigational Review Board (IRB) approval Recruitment through male clinic employees Only dominant, uninjured shoulder tested
 No prior shoulder, elbow, cervical spine

surgery

Methods
 Biodex® System 3 isometric testing unit

Methods
 Each subject endured three separate Biodex

testing sessions done in randomized order– “No Shirt”– Compression shirt (Under Armour®)– Compressive Posture Shirt® (Alignmed®) Fatigue controlled by > 3 days of rest

between testing sessions

Methods
 Scapular Posture Shirt, and Under Armour

shirts fit snuggly (XS-XXL)

Methods
 PT certified in Biodex dynamometer recorded data in

isokinetic resistance mode 2 testing speed: 180 deg/sec , 300 deg/sec
 All subject had a warm-up/stretch prior to testing Standardized testing position - standing position to avoid
scapular stabilization from seat back

Methods
 Standard isokinetic outcome measures

were recorded:peak torque (ft-lbs) ER
peak torque (ft-lbs) IR
peak torque/body weight ER
peak torque/body weight IR
max rep tot work ER

max rep tot work IRwork/body weight ER
work/body weight IR
total work ER
total work IR

Methods
 Means and standard deviations calculated
 Statistical analyses were carried out by astatistician using a 3 x 2 repeated measures
analysis of variance (ANOVA) Significance set at p<.05

Results
 14 Male subjects
 Ages 24-44yo (32.5 mean) All RHD No statistical correlation between demonstrated

strength and age, weight, or order of testingResults
 Peak torque in ER at slow speeds (180deg/sec) was improved with the compressive
Posture Shirt® vs controls
 No difference between the No Shirt and Under

Armour® compression shirt alone
 Most testing parameters showed somedifference between all three shirts

Results
120

brace

100

placebo80

Ft/lbsno shirt
60

40

200
peak torque peak torquepeak
ER 180IR 180torque/bw
deg/secdeg/sec
ER 180deg/secpeak
max rep tot max rep tot peak torque peak torquepeaktorque/bw work ER 180 work IR 180
ER 300IR 300torque/bw
IR 180deg/secdeg/secdeg/secdeg/sec
ER 300deg/secdeg/sec

peakmax rep tot max rep tot
torque/bw work ER 300 work IR 300
IR 300deg/secdeg/secdeg/sec

Results
60

brace50

placebo

Ft/lbs40

no shirt

3054.2 53.7 51.7
20

35.4

30.79 31.2

29.1 28.3 27.4

10

19.1 16.5 16.7

0peak torque ER 180 deg/sec

peak torque IR 180 deg/sec

peak torque/bw ER 180
deg/sec

peak torque/bw IR 180
deg/sec

Results
peak torque ER

peak torque/bw
ER

Compression
posture shirt

35.4

19.1

Compression only

30.79

16.5

31.2

16.7

14%

15%

increaseincreaseno shirt

Limitations
 All male subjects
 Lack of concurrent evaluation of specificscapular position

Discussion
 A form fitting posture shirt with variable tensions

may help increase Rotator Cuff RTC motor
strength in certain positions (especially at peaktorque ER)
 No difference between Compression Shirt andNo Shirt, therefore, compressive component ofsport garments do little to alter peak shoulder
strength, whereas proper scapular positioning
has a beneficial effect.

Discussion
 Future studies needed: with wear during

sport, females, various body sizes,
following the effects of fatigue or sports
specific moves.

END