Research into overhead pressing and the impact this has on the spine and shoudler

1. Australian Strength & Conditioning
Conference 2011
Dr Mark McKean Fitness Research 1
Dr Mark McKean PhD AEP CSCS
OVERHEAD PRESSING – EFFECT ON
SHOULDER GIRDLE AND SPINE
WHAT YOU WILL LEARN
 Evolution of shoulder posture
 Research aims
 Methods
 Results
 Conclusion
 Application
EVOLUTION OF SHOULDER
POSTURE
EVOLUTION OF THE SHOULDER
 The feature that has received the most attention in
functional analyses of fossils is the orientation of the
glenoid fossa.
 In hominoid primates the glenoid faces cranially
reflecting the importance of overhead limb postures,
while in modern humans the fossa faces more laterally
reflecting the typical lowered position of the upper limb.
X-rays showing glenoid-spine
angle of the scapulae of
a) a modern human,
b) KSD-VP-1/1,
c) a gorilla, and
d) chimpanzee.
Researchers suggest that either
1) the shoulder blades
underwent significant
modification once hominids
started walking on the
ground, or
2) 2) that they represent a
unique mode of locomotion
unlike any seen among the
few living hominids.
From Haile-Selassie et al,
2010.

2. Australian Strength & Conditioning
Conference 2011
Dr Mark McKean Fitness Research 2
NEANDERTHAL
 Scapula have high spines and the acromion is farther away
from the axis of rotation (Trinkaus 1983).
 Mediolaterally they are wider (Debenath and Tournepiche
1992).
 Thus Neanderthals were probably better at throwing
(Debenath and Tournepiche 1992) than their modern
contemporaries. This would make them better thrusters
and could relate to hunting techniques and tool knapping.
SCAPULA VARIATION
 Cursorial (running) mammals usually equipped
with longer, more narrow scapulae which is
positioned more vertically compared to
ambulatory (unspecialized) mammals.
 Fossorial (digging) and natatorial (swimming)
mammals equipped with triangular scapulae
and larger teres process.
 Provides greater leverage from teres major muscle
resulting in more powerful adduction of forelimb.
GLENOID FOSSA ORIENTATION
CHANGES WITH POSTURE
RESEARCH AIMS
Research aimed to quantify the overhead seated BB shoulder
press with respect to:
 Active ROM (AROM)of with Passive ROM (PROM) of
shoulder
 AROM of spine segments – cervical, thoracic, lumbar
 AROM of scapula
 Statistical analysis involved comparing
 ‘in front’ with ‘behind’ overhead pressing
 male to female
RESEARCH METHODS

3. Australian Strength & Conditioning
Conference 2011
Dr Mark McKean Fitness Research 3
PARTICIPANTS
 33 participants (18 males, 15 females)
 Sub-elite athletes - overhead/upper body sports who
perform S&C in training at least 12 months
 Age – 28.6 (4.7), 25.0 (4.1) years
 Height – 182.3 (8.7), 167.0 (4.8) cm
 Weight – 86.3 (10.3), 64.3 (4.4) kg
INITIAL MEASURES
 Assessed passive ROM of the shoulder girdle, and
anthrop measures of segment lengths
 Anthropometry
 Arm spam – 184.4 (7.9), 165.2 (4.8) cm
 Elbow span – 98.5 (8.6), 91.1 (5.2) cm
 Bi-acromial width – 40.7 (2.4), 36.7 (1.2) cm
PASSIVE SHOULDER GIRDLE ROM
(DEGREES – SD)
Measure Males Females Ideal
Shoulder flexion 158.8 (6.3) 167.9 (8.3) 160-180
Shoulder abduction 163.7 (13.0) 169.9 (7.0) 160-180
Shoulder horizontal flexion
(behind frontal plane)
28.0 (12.6) 33.5 (4.7)
No
consensus
Shoulder rotation internal
(length of external rotators)
44.5 (15.8) 46.9 (11.0) 70
Shoulder rotation external
(length of internal rotators)
84.7 (12.4) 89.3 (12.4) 90-100
SHOULDER FLEXION/ABDUCTION
TEST POSITION
Place arms above head with back flat
 Flexion – ideal 180o
 Abduction – ideal 180o
 (American Orthopaedic Society)
SHOULDER ROTATION TEST
 Start position - Arm bent 90o
 20o off floor in front – ideal length external rotators
 Arm touches floor above – ideal length internal rotators
SHOULDER JOINT ROM

4. Australian Strength & Conditioning
Conference 2011
Dr Mark McKean Fitness Research 4
0
20
40
60
80
100
120
140
160
180
200
Males
Females
Males typically
larger
Females typically
more flexible
3D MOTION ANALYSIS
 Participants performed 4 sets of overhead press in
seated unsupported position.
 In front and behind the head, using 3RM loads
 Started from top of movement with aid of spotter
 Self selected feet position
 Self selected tempo
RESULTS
CERVICAL SPINE
3RM
behind
Start
position
(degrees)
Minimum
(degrees)
Minimum
time (%)
Maximum
(degrees)
Maximum
time (%)
Range
(degrees)
Cervical
spine
flexion
Male 23.9 11.9 48.7 54.4 75.1 42.5
Female 17.1 13.8 59.0 30.6 66.1 16.8
Cervical
spine
rotation
Male 19.6 6.7 71.4 31.4 57.7 24.7
Female 11.4 3.5 74.6 17.5 54.7 14.0
3RM front
Cervical
spine
flexion
Male -8.5 -10.2 91.9 8.5 18.9 18.7
Female -8.4 -8.8 97.4 15.6 26.1 24.4
Cervical
spine
rotation
Male 15.2 12.5 63.8 18.5 26.0 6.0
Female 14.1 11.5 71.1 22.5 26.6 11.0
Normal curve 34-42o (Harrison et al 1997), Normal flexion/extension up to 45o Normal rotation up to 70o
Significant difference p>0.01 for all measures related to cervical flexion when comparing Front and Behind
the head shoulder press for both male and female participants.
Significant difference p>0.01 for Cervical rotation maximum time for both males and females and Cervical
rotation range for males when comparing Front and Behind the head shoulder press.
Smaller number
indicates top of press
Large number
indicates
bottom of the
press
-20
-10
0
10
20
30
40
50
60
Start position
(degrees)
Minimum
(degrees)
Maximum
(degrees)
Range (degrees)
Cervical Spine Flexion
Behind Male
Front Male
Behind Female
Front Female
Males achieved more
cervical range of
flexion during behind
head and females for
in front of the head
Behind head pressing
started with loss of
cervical curve and
Front with normal
cervical Lordosis
THORACIC & LUMBAR SPINE
3RM
behind
Start
position
(degrees)
Minimum
(degrees)
Minimum
time (%)
Maximum
(degrees)
Maximum
time (%)
Range
(degrees)
Thoracic
spine
flexion
Male -10.0 -21.8 16.5 -6.3 71.9 15.5
Female -3.3 -16.4 19.7 -1.9 88.2 14.6
Lumbar
spine
flexion
Male -1.1 -8.7 37.4 1.8 56.7 10.5
Female 9.7 2.8 28.4 11.2 76.9 8.4
3RM front
Thoracic
spine
flexion
Male 10.5 -27.8 32.9 -13.6 74.5 14.2
Female 8.4 -24.5 38.5 -12.7 76.5 11.9
Lumbar
spine
flexion
Male -7.4 -13.2 55.2 -3.2 53.2 10.0
Female 3.2 -3.1 48.5 6.3 49.0 9.4
Significant difference p>0.01 for all Thoracic flexion measures for females when comparing Front and Behind the head shoulder press.
Significant difference p>0.01 for Thoracic flexion minimum time and maximum angle when comparing Front and Behind the head shoulder press
for males.
Significant difference p>0.05 for lumbar flexion start angle, minimum angle, minimum time and maximum time when comparing Front and Behind
the head shoulder press for females.
Significant difference p>0.05 for lumbar flexion minimum time when comparing Front and Behind the head shoulder press for males.
Negative reading
indicates thoracic
extension
Negative reading
indicates lumbar
lordosis

5. Australian Strength & Conditioning
Conference 2011
Dr Mark McKean Fitness Research 5
-30
-25
-20
-15
-10
-5
0
5
10
15
20
Start position
(degrees)
Minimum
(degrees)
Maximum
(degrees)
Range
(degrees)
Thoracic Flexion
Behind Male
Front Male
Behind Female
Front Female
Negative reading
indicates thoracic
extension
Minimums occurred
with in bottom half of
movement, whilst
maximums occurred in
top half
OH press to front
achieved significantly
more thoracic
extension than to
behind the head
-15
-10
-5
0
5
10
15
Start position
(degrees)
Minimum
(degrees)
Maximum
(degrees)
Range
(degrees)
Lumbar Flexion
Behind Male
Front Male
Behind Female
Front Female
Females started with
increased lumbar
flexion, males in almost
normal lordosis
Females stayed mostly
in an increased lumbar
flexion posture
Males stayed mostly in
a lumbar lordotic
posture
SHOULDER MOTION
3RM
behind
Start
position
(degrees)
Minimum
(degrees)
Minimum
time (%)
Maximum
(degrees)
Maximum
time (%)
Range
(degrees)
Shoulder
flexion
Male 3.3 144.7 7.3 141.4
Female 22.2 155.0 14.6 132.8
Shoulder
abduction
Male 54.8 124.3 2.0 69.5
Female 56.6 123.4 3.2 66.8
Shoulder
rotation
Male 92.3 92.8 87.9 36.5 2.5 56.3
Female 79.3 79.3 99.6 25.9 6.5 53.5
Horizontal
flexion
Male -65.7 -66.9 75.1 -34.8 7.4 32.1
Female -57.4 -60.1 79.8 -32.1 6.7 28.0
3RM front
Shoulder
flexion
Male 6.7 135.9 1.4 129.1
Female 10.8 147.3 12.3 136.5
Shoulder
abduction
Male 32.8 125.7 1.0 92.9
Female 33.4 124.7 1.6 91.3
Shoulder
rotation
Male 66.5 67.7 85.5 25.3 4.0 42.5
Female 44.5 46.2 86.1 13.5 12.3 32.8
Horizontal
flexion
Male -61.7 -66.3 83.7 -37.5 7.9 28.9
Female -69.7 -70.2 96.4 -31.1 3.5 39.1
Significant difference p>0.05 for shoulder flexion maximum time for males and abduction starting angle and shoulder abduction range for males and
females when comparing Front and Behind the head shoulder press.
Significant difference p>0.05 for shoulder rotation minimum time for females and shoulder rotation starting angle, shoulder rotation minimum angle,
maximum angle, and range for males and females when comparing Front and Behind the head shoulder press.
Significant difference p>0.01 for shoulder horizontal flexion minimum time and range when comparing Front and Behind the head shoulder press for
females.
Number indicates
external rotation
Negative number
indicates behind frontal
plane
0
20
40
60
80
100
120
140
160
180
Start position
(degrees)
Maximum
(degrees)
Range
(degrees)
Shoulder Flexion
Male Behind
Male Front
Female Behind
Female Front
Passive ROM
Males – 159o
Females – 168o
0
20
40
60
80
100
120
140
Start position
(degrees)
Maximum
(degrees)
Range
(degrees)
Shoulder Abduction
Male Behind
Male Front
Female Behind
Female Front
Passive ROM
Males – 164o
Females – 170o
0
10
20
30
40
50
60
70
80
90
100
Start position
(degrees)
Maximum
(degrees)
Range
(degrees)
Shoulder Rotation
Male Behind
Male Front
Female Behind
Female Front
Passive ROM
Males – 85o
Females – 90o
Passive ROM
exceeded by males in
behind the head OH
press
At bottom of OH press
AROM of shoulder
rotation well within
PROM limits

6. Australian Strength & Conditioning
Conference 2011
Dr Mark McKean Fitness Research 6
SCAPULA MOTION
3RM behind
Start position
(degrees)
Minimum
(degrees)
Minimum
time (%)
Maximum
(degrees)
Maximum
time (%)
Range
(degrees)
Scapula
position in X
Male -50.0 -55.1 52.5 -35.6 30.4 19.5
Female -43.5 -47.7 56.6 -30.8 18.6 17.0
Scapula
position in Y
Male 15.2 15.2 90.9 48.0 4.1 32.7
Female 20.0 20.0 99.9 48.6 9.6 28.6
Scapula
position in Z
Male -63.9 -65.1 84.3 -37.4 3.6 27.7
Female -68.5 -69.9 87.6 -42.2 5.4 27.8
3RM front
Scapula
position in X
Male -54.4 -60.7 63.4 -36.8 16.2 23.9
Female -46.4 -51.8 66.0 -30.2 21.5 21.6
Scapula
position in Y
Male 15.2 12.7 90.9 49.1 8.5 36.5
Female 13.4 13.4 99.8 48.8 6.1 35.4
Scapula
position in Z
Male -52.7 -56.2 48.7 -34.2 28.0 22.0
Female -51.7 -59.1 49.9 -37.8 30.7 21.3
0
5
10
15
20
25
30
35
40
in 'X' in 'Y' in 'Z'
Scapula ROM
Male Behind
Male Front
Female Behind
Female Front
Movement about ‘X’
indicates Rotation –
Greater rotation in
Front
Movement about ‘Y’
indicates Tilting –
Greater Tilting in
Front
Movement about ‘X’
indicates Winging –
Greater Winging in
Behind
OH PRESSING
Key points:
 AROM generally stays within PROM of the shoulder for
 Flexion, Abduction, Horizontal flexion
 Similar AROM range between genders for all measures
except Shoulder rotation.
 Significant differences between genders for starting
spine postures
 Resulted in thoracic extension during movement
OH PRESS BEHIND THE HEAD
Key points:
 Greater movement of the cervical spine into cervical
flexion and loss of normal curve
 Requires greater ROM at shoulder in rotation than front
OH press by more than 30o and this is reached at the top
of the movement
 Produced greater ‘winging’ of the scapula than Front
OH PRESS IN FRONT OF HEAD
Key points:
 Allows more normal thoracic kyphosis commence
position
 Significantly greater thoracic extension
 Produced significantly greater scapula ‘Rotation’ and
‘Tilting’ than Behind the head press.
MALES
Key points:
 Start OH pressing with normal lumbar curve
 Able to maintain lordosis through most movements
 AROM of shoulder rotation during Behind press
exceeded PROM

7. Australian Strength & Conditioning
Conference 2011
Dr Mark McKean Fitness Research 7
FEMALES
Key points:
 Start OH pressing with increased lumbar flexion and loss
of lordosis
 Stay mostly in this posture during the press with greater
maximum lumbar flexion than males
CONCLUSION
 Shoulder press active ROM takes the shoulder
musculature through ranges within normal passive
motion except for males rotation.
 Segmental spinal flexion/extension occurs within each
phase,
 Cervical spine moves through large ROM in both flexion
and rotation –
 males > in BN press,
 females > in Front press
TAKE HOME MESSAGE
 Shoulder rotation ROM must be assessed and corrected
prior to overhead pressing
 Poor PROM of shoulder may influence cervical spine
posture during OH pressing
 If Rotation ROM is corrected, behind the neck overhead
pressing works shoulder through normal ROM.
 DB press may be suitable short term alternative
 Trunk and spine stability are important factors to
consider when doing seated or standing overhead press.
 A lack of stability in the spine will increase flexion-
extension moments during overhead pressing and may
require additional support via a back support.
 Females may require additional trunk-core training to
provide increased support to lumbar posture
 Different athletes may suit different OH press based on
posture and stability.
DR MARK MCKEAN
PHD CSCS AEP MESSA
 Post Doctoral Research Fellow
 University of Sunshine Coast
 Australian Institute of Fitness Research
 mmckean@usc.edu.au