Comparison of the Middle and Lower Serratus
Anterior Muscle Activities during Various Wall
Push-up Plus Exercises
Won-gyu yoo1)
1) Depar tment of Physical T herapy, College of Biomedical Science and Engineering, Inje Unive rsity
and Elderly Life Redesig n Institute: 607 Oban gdong, Gimhae, Gye ongsangnam- do 621-749, Republic
of Korea. TEL: +82 55-320-3994, FAX:+82: 55-329-1678, E-mail: won7y@inje.ac.kr
Abstract. [Pur pose] This stud y compared the effec ts of wall push-up plus cond itions on activation of the m iddle
serrat us anterior ( MSA) and lower serratus a nterior (LSA), and investigat ed which exercise selectively act ivated
each part of the s erratu s anterior. [Subjects] Sixteen subje cts were recr uited. [Method s] Surface electrod es were
placed over the middle a nd lower serratu s anterior. The subjec ts performe d the wall push-up plus exer cise un-
der three conditions. [ Result] Cond ition 3 (39.9 ± 12.4%) significa ntly i ncreased MSA activity compared to con-
dition 1 (32.0 ± 16.8%). C ondition 2 (40.7 ± 15.2%) sign ificantly increased LSA a ctivity compared t o condition 1
(32.6 ± 10.5%). [Conclusion] We think t hat each part of t he serrat us anterior mus cle is activated dif ferently accord-
ing to the prot raction dir ection and sur face condition du ring wall push -up plus exercise.
Key words: Electromyography, Serratus anterior, Wall push-up exercise
(This art icle was submitt ed Aug. 15, 2012, and was accepte d Sep. 14, 2012)
INT RODUCTION
Scapular setting exercises are used to stabilize the
shoulder complex. Closed kinetic-chain exercises, such as
a standard push up or push up plus, have been shown to
stimulate mechanoreceptors that contribute to shoulder joint
stabilization1, 2). Weakness of the serratus anterior causes
poor scapular orientation and instability, thereby conributing
to pathologic kinematics such as impingement3). The push
up plus exercise is used to induce scapular elevation, and
upward rotation needs to have minimal effect on the upper
trapezius and selective stimulation of the serratus anterior
and lower trapezius4). The serratus anterior has many
branches and can be divided into the upper, middle, and
lower parts5, 6). Some researchers have shown that the middle
and lower parts of serratus anterior muscle are important
for stabilizing scapular movement, and that activating the
middle and lower part of the serratus anterior muscle might
be an effective form of intervention7, 8). Wall push-ups can
be used as a low-level strengthening exercise for shoulder
muscle rehabilitation and can prepare the shoulder muscles
before advancing to floor push-ups. Wall push-ups are also
a safe exercise for sports players after shoulder surgery.
Therefore, the purpose of the present study was to compare
the effects of wall push-up plus conditions on the selective
activation of the middle and lower serratus anterior.
SUBJECTS A ND METHODS
This study was performed with sixteen males aged 20–29
years (26 ± 4.0 yrs), with a weight of 65 ± 6.3 kg and height
of 176 ± 8.2 cm as subjects. The subjects had no history of
traumatic injury or discomfort in their upper extremities
during the past 6 months. Electromyography (EMG) signals
were amplified, and sampled at 1000 Hz using a MP 150
system (Biopack System, Santa Barbara, CA, USA). The
surface electrodes were placed on the dominant right side
of the middle serratus anterior (MSA), at approximately the
mid-axillary line of the right side over the 5th rib, and the
lower serratus anterior (LSA), on the belly of the muscle
that branched to the 7th rib9, 10). EMGs of maximal voluntary
isometric contractions were recorded to enable normal-
ization of the EMG amplitude. The subjects performed wall
push-up plus exercises in a standing position under 3 condi-
tions: condition 1 was a stable wall push-up plus, with the
shoulder at 90 degrees of flexion; condition 2 was a stable
wall push-up plus, with the shoulder at 120 degrees flexion;
and condition 3 was a labile wall push-up plus exercise with
the shoulder at 90 degrees flexion. An air cushion ball (15
inches) was used as the labile wall surface. Elbow flexion
during the wall push-up plus was restricted according to
the examiner’s instructions. The SPSS statistical package
(version 12.0; SPSS, Chicago, IL, USA) was used for statis-
tical analysis, and the statistical significance of differences
was examined by repeated one-way ANOVA, with signifi-
cance accepted at value of p < 0.05.
RE SU LT S
Condition 3 (39.9 ± 12.4%) significantly increased MSA
J. Phys. Ther. Sci.
25: 15 3– 154, 2013
