Prediction of Scapular Dyskinesis Through Electromyographic Indices of Scapulothoracic Muscles in Female Overhead Athletes

Leila Ghanbari, Mohammadhossein Alizadeh, Hooman Minoonejad, Seyed Hossein Hosseini


Background: Shoulder joint function and the athletic performance of overhead
athletes are influenced by scapular dyskinesis (SD) due to its high prevalence
among these athletes and the motor interaction between the scapula and the arm.
The present study investigated the prediction of SD through the electromyographic
indices of scapulothoracic muscles in female overhead athletes.
Methods: The present descriptive-correlational study was carried out on 60
female volleyball, handball, basketball, and badminton athletes. The lateral
scapular slide test was used to examine their SD. The required electromyography
and electrogoniometry data was recorded simultaneously to measure the activity
and onset time of scapulothoracic muscles, including upper trapezius (UT),
lower trapezius (LT), and serratus anterior (SA). The collected data was analyzed
using Spearman correlation and multiple regression tests.
Results: Significant correlations were found between all electromyographic
variables and SD (P<0.01). The regression effects of all predictive variables on SD
were significant (P=0.001). In terms of predictive power, UT/SA co-contraction
(β=0.765), UT/LT co-contraction (β=0.716), LT onset time (β=0.672), LT activity
(β=0.612), and SA onset time (β=0.576) had the highest regression effects on
SD, respectively. The analysis of the study model showed that there was a strong
correlation (r=0.694) between the predictive variables and SD and that the
independent variables predicted 48% of the variance.
Conclusion: The presence of imbalance in the scapulothoracic muscles of
overhead athletes with SD indicates that athletes should be monitored by
coaches, physiotherapists, and physicians for SD screening. It is also necessary
to carry out prospective studies to examine and explore other variables related
to SD.


Electromyography, Muscle onset time, Overhead athletes, Scapular dyskinesis, Scapulothoracic muscles

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Kibler BW, Sciascia A, Wilkes T. Scapular dyskinesis and its

relation to shoulder injury. Journal of the American Academy

of Orthopaedic Surgeons 2012; 20(6): 364-372. doi: 10.5435/


Cools AM, et al. Prevention of shoulder injuries in overhead

athletes: a science-based approach. Brazilian journal of physical

therapy 2015; (AHEAD). 00-00. doi: 10.1590/bjpt-rbf.2014.0109.

Ekstrom RA, Soderberg GL, Donatelli RA. Normalization

procedures using maximum voluntary isometric contractions

for the serratus anterior and trapezius muscles during surface

EMG analysis. J Electromyogr Kinesiol 2005; 15(4): 418-428.

Kibler WB, Ludewig PM, McClure PW, Michener LA, Bak

K, Sciascia AD .Clinical implications of scapular dyskinesis

in shoulder injury: the 2013 consensus statement from the

‘Scapular Summit’, British journal of sports medicine 2013;


McClure PW, Michener LA, Karduna AR. Shoulder function and

-dimensional scapular kinematics in people with and without

shoulder impingement syndrome. Physical therapy 2006; 86(8):


Kibler BW. The role of the scapula in athletic shoulder function.

The American journal of sports medicine 1998; 26(2): 325-337.

Ludewig PM, Cook TM. Alterations in shoulder kinematics

and associated muscle activity in people with symptoms of

shoulder impingement. Physical therapy 2000; 80(3): 276-291.

Paine R, Voight ML. The role of the scapula. International

journal of sports physical therapy 2013; 8(5): 617. DOI: 10.2519/


Park JY, Hwang JT, Oh KS, Kim SJ, Kim NR, Cha MJ. Revisit

to scapular dyskinesis: three-dimensional wing computed

tomography in prone position. J Shoulder Elbow Surg 2014;

(6) :821-8.

Cricchio M, Frazer C. Scapulothoracic and scapulohumeral

exercises: a narrative review of electromyographic studies.

Journal of Hand Therapy 2011; 24(4): 322-334.


Hardwick DH, Beebe JA, McDonnell MK, Lang CE. A comparison

of serratus anterior muscle activation during a wall slide exercise

and other traditional exercises. J Orthop Sports Phys Ther 2006;

(12): 903-10. DOI: 10.2519/jospt.2006.2306.

Huang TS, Huang Hy, Wang TG, Tsai YS, Lin JJ. Comprehensive

classification test of scapular dyskinesis: A reliability study.

Manual therapy 2015; 20(3): 427-432.


Cools A, Declercq GA, Cambier DC, Mahieu NN, Witvrouw EE.

Trapezius activity and intramuscular balance during isokinetic

exercise in overhead athletes with impingement symptoms.

Scandinavian journal of medicine & science in sports 2007;

(1): 25-33.

Moraes GF, Faria CD, Teixeira-Salmela LF. Scapular muscle

recruitment patterns and isokinetic strength ratios of the shoulder

rotator muscles in individuals with and without impingement

syndrome. J Shoulder Elbow Surg 2008; 17(1 Suppl): 48S-53S.

Seitz AL, Uhl TL. Reliability and minimal detectable

change in scapulothoracic neuromuscular activity. Journal of

Electromyography and Kinesiology 2012; 22(6): 968-974. doi.


Oliveira VMAd, Batista LdSP, Pirauá ALT, Pitangui ACR, Araújo

RCd. Electromyographic activity and scapular dyskenesia in

athletes with and without shoulder impingement syndrome.

Revista Brasileira de Cineantropometria & Desempenho Humano

; 15(2): 193-203.

Helgadottir H, Kristjansoon E, Einarsson E, Karduna A, Jonsson

Jr H. Altered activity of the serratus anterior during unilateral

arm elevation in patients with cervical disorders. Journal of

electromyography and kinesiology 2011; 21(6): 947-953. doi.


Lucas KR, Rich PA, Polus BI. Muscle activation patterns in

the scapular positioning muscles during loaded scapular

plane elevation: the effects of latent myofascial trigger points.

Clinical Biomechanics 2010; 25(8): 765-770.


Reeser JC, Joy EA, Porucznik CA, Berg RL, Colliver DO EB,

Willick SE. Risk factors for volleyball-related shoulder pain

and dysfunction. Pm&r 2010; 2(1): 27-36.


Cools AM, Witvouw EE, Declercq GA, Danneels LA, Cambier

DC. Scapular muscle recruitment patterns: trapezius muscle

latency with and without impingement symptoms. The American

journal of sports medicine 2003; 31(4): 542-549.

Myers JB, Hwang JH, Pasquale MR, Blackburn GT, Lephart SM.

Rotator cuff coactivation ratios in participants with subacromial

impingement syndrome. Journal of science and medicine in sport

; 12(6): 603-608.

Lopes AD, Timmons MK, Grover M, Ciconelli RM, Michener

LA. Visual scapular dyskinesis: kinematics and muscle activity

alterations in patients with subacromial impingement syndrome.

Arch Phys Med Rehabil 2015; 96(2): 298-306.


Chester R, Smith TO, Hooper L, Dixon J. The impact of

subacromial impingement syndrome on muscle activity

patterns of the shoulder complex: a systematic review of

electromyographic studies. BMC Musculoskelet Disord 2010;


Page P ,Frank C, Lardner R. Assessment and treatment of muscle

imbalance: the Janda approach. Human Kinetics; 2010.

Huang TS, Lin JJ, Ou HL, Chen YT. Movement Pattern of

Scapular Dyskinesis in Symptomatic Overhead Athletes. Sci

Rep 2017; 7(1): 6621. PMCID: PMC5529546 PMID: 28747702


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