Reliability of Scapular Classification in Examination of Professional Baseball Players
Rent the article at a discountRent now
* Final gross prices may vary according to local VAT.Get Access
Clinically evaluating the scapulothoracic joint is challenging. To identify scapular dyskinesis, clinicians typically observe scapular motion and congruence during self-directed upper extremity movements. However, it is unclear whether this method is reliable.
We therefore determined the interrater reliability of a scapular classification system in the examination of professional baseball players.
Seventy-one healthy uninjured professional baseball players between the ages of 18 and 32 years volunteered to participate. We used a digital video camera to film five repetitions of scapular plane elevation while holding a 2-pound weight. Four examiners then independently classified the motions on video into one of four types. Interrater reliability analysis using the kappa (k) statistic was performed for: (1) classifying each scapula into one of the four types; (2) classifying each scapula as being abnormal (Types I–III) or normal (Type IV); and (3) classifying both scapula as both being symmetric (both normal or both abnormal) or asymmetric (one normal, one abnormal).
We found low reliability for all analyses. In classifying each scapula as one of the four types, reliability was k = 0.245 for the left limb and k = 0.186 for the right limb. When considering the dichotomous classifications (abnormal versus normal), reliability was k = 0.264 for left and k = 0.157 for right. For bilateral symmetry/asymmetric, reliability was k = 0.084.
We found low reliability of visual observation and classification of scapular movement.
Current evaluation strategies for evaluating subtle scapular abnormalities are limited.
Level of Evidence
Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
- Bourne DA, Choo AM, Regan WD, MacIntyre DL, Oxland TR. Three dimensional rotation of the scapula during functional movements: an in-vivo study in healthy volunteers. J Shoulder Elbow Surg. 2007;16:150–162. CrossRef
- Fleisig GS, Barrentine SW, Zheng N, Escamilla RF, Andrews J. Kinematic and kinetic comparison of baseball pitching among various levels of development. J Biomech. 1999;32:1371–1375. CrossRef
- Fleiss JL. Measuring nominal scale agreement among many raters. Psychol Bull. 1971;76:378–382. CrossRef
- Fleiss JL, Nee JCM, Landis JR. Large sample variance of kappa in the case of different sets of sample variance of kappa in the case of different sets of raters. Psychol Bull. 1979;86:974–977. CrossRef
- Forthomme B, Crielaard JM, Croisier JL. Scapular positioning in athlete’s shoulder. Sports Med. 2008;38:369–386. CrossRef
- Kibler WB. The role of the scapula in the overhead throwing motion. Contemp Orthop. 1991;22:525–532.
- Kibler WB. The role of the scapula in athletic shoulder function. Am J Sports Med. 1998;26:325–337.
- Kibler WB, Uhl TL, Maddux JW, Brooks PV, Zeller B, McMullen J. Qualitative clinical evaluation of scapular dysfunction: a reliability study. J Shoulder Elbow Surg. 2002;11:550–556. CrossRef
- Konda S, Yanai T, Sakurai S. Scapular rotation to attain the peak shoulder external rotation in tennis serve. Med Sci Sports Exerc. 2010;42:1745–1753. CrossRef
- Laudner KG, Stanek JM, Meister K. Differences in scapular upward rotation between baseball pitchers and position players. Am J Sports Med. 2007;35:2091–2095. CrossRef
- McClure PW, Michener LA, Sennett BJ, Karduna AR. Direct 3-dimensional measurement of scapular kinematics in vivo. J Shoulder Elbow Surg. 2001;10:269–277. CrossRef
- McClure PW, Tate AR, Kareha S, Irwin D, Zlupkp E. A clinical method for identifying scapular dyskinesis, Part 1: reliability. J Athl Train. 2009;44:160–164. CrossRef
- Myers JB, Laudner KG, Pasquale MR, Bradley JP, Lephart SM. Scapular position and orientation in throwing athletes. Am J Sports Med. 2005;33:263–271. CrossRef
- Nijs J, Roussel N, Struyf F, Mottram S, Meeusen R. Clinical assessment of scapular positioning in patients with shoulder pain: state of the art. J Manipulative Physiol Ther. 2007;30:69–75. CrossRef
- Oyama S, Myers JB, Wassinger CA, Ricci D, Lephart SM. Asymmetric resting scapular posture in healthy overhead athletes. J Athl Train. 2008;43:565–570. CrossRef
- Reid M, Elliott B, Alderson J. Lower-limb coordination and shoulder joint mechanics in the tennis serve. Med Sci Sports Exerc. 2008;40:308–315. CrossRef
- Sim J, Wright CC. The kappa statistic in reliability studies: use interpretation, and sample size requirements. Phys Ther. 2005;85:257–268.
- Tate AR, McClure P, Kareha S, Irwin D, Barbe MF. A clinical method for identifying scapular dyskinesis, Part 2: validity. J Athl Train. 2009;44:165–173. CrossRef
- Uhl TL, Kibler WB, Gecewich B, Tripp BL. Evaluation of clinical assessment methods for scapular dyskinesis. Arthroscopy. 2009;25:1240–1248. CrossRef
- Reliability of Scapular Classification in Examination of Professional Baseball Players
Clinical Orthopaedics and Related Research®
Volume 470, Issue 6 , pp 1540-1544
- Cover Date
- Print ISSN
- Online ISSN
- Additional Links
- Industry Sectors
- Author Affiliations
- 1. Physiotherapy Associates Scottsdale Sports Clinic, 9917 N 95th Street, Scottsdale, AZ, 85258, USA
- 2. Lexington Clinic Sports Medicine and Shoulder Center, Lexington, KY, USA
- 3. The Orthopaedic Clinic Association (TOCA), Scottsdale, AZ, USA
- 4. Milwaukee Brewers Baseball Club, Milwaukee, WI, USA
- 5. Armstrong Atlantic University, Savannah, GA, USA