Modifying a shrug exercise can facilitate the upward rotator muscles of the scapula

      Abstract

      Background

      Scapular dyskinesis, characterised by drooping scapulae and reduced upward rotation, has been implicated in the presentation of a number of shoulder disorders. Traditionally, in shoulder rehabilitation programmes, the shrug exercise has been prescribed to facilitate upward rotation of the scapula by strengthening the upper trapezius muscle. The aim of this research was to compare muscle activation levels during the standard shrug and the upward rotation shrug in a normal and pathological population.

      Methods

      Surface electrodes recorded electromyographical activity from upper trapezius, middle trapezius, lower trapezius and serratus anterior muscles in 23 normal participants and 14 participants with multi-directional shoulder instability. Participants completed 10 trials of the standard shrug exercise at 0° of shoulder abduction and the upward rotation shrug exercise at 30° of shoulder abduction in the coronal plane. Muscle activity was expressed as a percentage of maximum voluntary isometric contraction.

      Findings

      The four muscles tested performed at a higher intensity during the modified shrug than the standard shrug. Upper trapezius and lower trapezius activity was significantly greater (P < 0.05) in both populations. Though for middle trapezius and serratus anterior muscles, the modified shrug was statistically significant only in the normal population, P = 0.031 and P = <0.001 respectively.

      Interpretation

      The upward rotation shrug is a more effective exercise for eliciting muscle activity of the upper and lower trapezius than the standard shrug in a normal and multi-directional instability population. Clinically, the upward rotation shrug might be useful to address scapular dyskinesis involving drooping shoulders and reduced scapula upward rotation.

      Keywords

      To read this article in full you will need to make a payment
      Subscribe to Clinical Biomechanics
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Braun S.
        • Kokmeyer D.
        • Millett P.J.
        Shoulder injuries in the throwing athlete.
        J. Bone Joint Surg. Am. 2009; 91: 966-978
        • Burkhead Jr., W.Z.
        • Rockwood Jr., C.A.
        Treatment of instability of the shoulder with an exercise program.
        J. Bone Joint Surg. Am. 1992; 74: 890-896
        • Chapman A.R.
        • Vicenzino B.
        • Blanch P.
        • Knox J.J.
        • Hodges P.W.
        Leg muscle recruitment in highly trained cyclists.
        J. Sports Sci. 2006; 24: 115-124
        • Corder G.W.
        • Foreman D.I.
        Nonparametric Statistics for Non-statisticians.
        John Wiley & Sons, Inc., New Jersey, Hodoken2009
        • Delagi E.F.
        • Perotto A.
        Anatomic Guide for the Electromyographer.
        Charles C. Thomas, Springfield2005
        • Franettovich M.
        • A.R., C.
        • Blanch P.
        • Vicenzino B.
        Continual use of augmented low-dye taping increases arch height in standing but does not influence neuromotor control of gait.
        Gait Posture. 2010; 31: 247-250
        • Geiringer S.R.
        Anatomic Localization for Needle Electromyography.
        Hanley & Belfus, Philadelphia1999
        • Graichen H.
        • Hinterwimmer S.
        • von Eisenhart-Rothe R.
        • Vogl T.
        • Englmeier K.H.
        • Eckstein F.
        Effect of abducting and adducting muscle activity on glenohumeral translation, scapular kinematics and subacromial space width in vivo.
        J. Biomech. 2005; 38: 755-760
        • Hintermeister R.A.
        • Lange G.W.
        • Schultheis J.M.
        • Bey M.J.
        • Hawkins R.J.
        Electromyographic activity and applied load during shoulder rehabilitation exercises using elastic resistance.
        Am. J. Sports Med. 1998; 26: 210-220
        • Ide J.
        • Maeda S.
        • Yamaga M.
        • Morisawa K.
        • Takagi K.
        Shoulder-strengthening exercise with an orthosis for multidirectional shoulder instability: quantitative evaluation of rotational shoulder strength before and after the exercise program.
        J. Shoulder Elbow Surg. 2003; 12: 342-345
        • Kibler W.B.
        • Sciascia A.
        Current concepts: scapular dyskinesis.
        Br. J. Sports Med. 2010; 44: 300-305
        • Levangie P.K.
        • Norkin C.C.
        Joint Structure and Function: A Comprehensive Analysis.
        F.A. Davis Company, Philadelphia2011
        • Ludewig P.M.
        • Cook T.M.
        Alterations in shoulder kinematics and associated muscle activity in people with symptoms of shoulder impingement.
        Phys. Ther. 2000; 80: 276-291
        • Malanga G.A.
        • Jenp Y.N.
        • Growney E.S.
        • An K.N.
        EMG analysis of shoulder positioning in testing and strengthening the supraspinatus.
        Med. Sci. Sports Exerc. 1996; 28: 661-664
        • Misamore G.W.
        • Sallay P.I.
        • Didelot W.
        A longitudinal study of patients with multidirectional instability of the shoulder with seven- to ten-year follow-up.
        J. Shoulder Elbow Surg. 2005; 14: 466-470
        • Moraes G.F.
        • Faria C.D.
        • Teixeira-Salmela L.F.
        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: 48S-53S
        • Myers J.B.
        • Pasquale M.R.
        • Laudner K.G.
        • Sell T.C.
        • Bradley J.P.
        • Lephart S.M.
        On-the-field resistance-tubing exercises for throwers: an electromyographic analysis.
        J. Athl. Train. 2005; 40: 15-22
        • Neer II, C.S.
        • Foster C.R.
        Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder. A preliminary report.
        J. Bone Joint Surg. Am. 1980; 62: 897-908
        • Ogston J.
        • Ludewig P.
        Differences in 3-dimensional shoulder kinematics between persons with multidirectional instability and asymptomatic controls.
        Am. J. Sports Med. 2007; 35: 1361-1370
        • Reinold M.M.
        • Escamilla R.
        • Wilk K.E.
        Current concepts in the scientific and clinical rationale behind exercises for glenohumeral and scapulothoracic musculature.
        JOSPT. 2009; 39: 105-117
        • Struyf F.
        • Nijs J.
        • Baeyens J.P.
        • Mottram S.
        • Meeusen R.
        Scapular positioning and movement in unimpaired shoulders, shoulder impingement syndrome, and glenohumeral instability.
        Scand. J. Med. Sci. Sports. 2011; 21: 352-358
        • Tillander B.
        • Lysholm M.
        • Norlin R.
        Multidirectional hyperlaxity of the shoulder: results of treatment.
        Scand. J. Med. Sci. Sports. 1998; 8: 421-425
        • von Eisenhart-Rothe R.
        • Mayr H.
        • Hinterwimmer S.
        • Graichen H.
        Simultaneous 3D assessment of glenohumeral shape, humeral head centering and scapular positioning in atraumatic shoulder instability: a magnetic resonance based in vivo analysis.
        Am. J. Sports Med. 2009; 38: 375-381
        • Wadsworth D.J.
        • Bullock-Saxton J.E.
        Recruitment patterns of the scapular rotator muscles in freestyle swimmers with subacromial impingement.
        Int. J. Sports Med. 1997; 18: 618-624
        • Watson L.A.
        • Pizzari T.
        • Balster S.
        Thoracic outlet syndrome part 1: clinical manifestations, differentiation and treatment pathways.
        Man. Ther. 2009; 14: 586-595
        • Watson L.A.
        • Pizzari T.
        • Balster S.
        Thoracic outlet syndrome part 2: conservative management of thoracic outlet.
        Man. Ther. 2010; 15: 305-314
        • Wickham J.
        • Pizzari T.
        • Stansfeld K.
        • Burnside A.
        • Watson L.
        Quantifying ‘normal’ shoulder muscle activity during abduction.
        J. Electromyogr. Kinesiol. 2010; 20: 212-222
        • Yasojima T.
        • Kizuka T.
        • Noguchi H.
        • Shiraki H.
        • Mukai N.
        • Miyanaga Y.
        Differences in EMG activity in scapular plane abduction under variable arm positions and loading conditions.
        Med. Sci. Sports Exerc. 2008; 40: 716-721