title: Interrater and intrarater reliability of the pectoralis minor muscle length measurement in subjects with and without shoulder impingement symptoms.
abstract: Measuring the pectoralis minor muscle length (PML) is of clinical interest, as a short PML has been associated with a decrease of scapular posterior tilting and shoulder pain. However, as no reliability data are available at present, the objective of this study was to examine the inter- and intrarater reliability of the PML measurement in both subjects with and without shoulder impingement symptoms (SIS). Therefore, two assessors performed the PML measurement (3 times/shoulder) in 25 patients with SIS and 25 pain-free controls. Both assessors were blinded for each other's findings. For reliability testing, intra-class coefficients (ICCs; model 2,1) and standard errors of measurements were calculated. Intrarater reliability analysis resulted with ICCs ranging from 0.87 (Standard error of measurement (SEM) 0.21-0.27%) (symptomatic) to 0.93 (SEM 0.19-0.30%) (asymptomatic) in patients with SIS, representing excellent test-retest agreement. Healthy subjects presented with ICCs ranging from 0.76 (SEM 0.29-0.32%) (dominant side) to 0.87 (SEM 0.21-0.32%) (non-dominant side), representing good test-retest agreement. ICCs and SEMs on the symptomatic and asymptomatic side (0.48 and 0.46%; 0.56 and 0.61%) in SIS patients, and on the two sides (non-dominant; 0.47 and 0.45%, dominant; 0.53 and 0.38% respectively) in healthy subjects showed moderate interrater reliability and low dispersion of the measurement errors. We concluded that the PML measurement has good to excellent intrarater reliability and poor to moderate interrater reliability.
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium; Chronic Pain and Chronic Fatigue Research Group (Pain in Motion). Electronic address: Filip.struyf@uantwerpen.be.
authors.forename: Filip
authors.initials: F
authors.lastname: Struyf
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium; Chronic Pain and Chronic Fatigue Research Group (Pain in Motion); Rehabilitation Sciences and Physiotherapy, Ghent University, Ghent, Belgium.
authors.forename: Mira
authors.initials: M
authors.lastname: Meeus
authors.affiliation: StatUa Center for Statistics, University of Antwerp, Belgium.
authors.forename: Erik
authors.initials: E
authors.lastname: Fransen
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium; Chronic Pain and Chronic Fatigue Research Group (Pain in Motion).
authors.forename: Nathalie
authors.initials: N
authors.lastname: Roussel
authors.affiliation: AZ Monica, Deurne, Belgium.
authors.forename: Nick
authors.initials: N
authors.lastname: Jansen
authors.affiliation: Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: Truijen
authors.affiliation: Chronic Pain and Chronic Fatigue Research Group (Pain in Motion); Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium.
authors.forename: Jo
authors.initials: J
authors.lastname: Nijs
mesh_terms: D000328:Adult; D000368:Aged; D000886:Anthropometry; D016022:Case-Control Studies; D061827:Dimensional Measurement Accuracy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000175:diagnosis / Q000209:etiology; D015588:Observer Variation; D010147:Pain Measurement; D010369:Pectoralis Muscles / Q000033:anatomy & histology* / Q000502:physiology; D011446:Prospective Studies; D012016:Reference Values; D012540:Scapula; D012680:Sensitivity and Specificity; D019534:Shoulder Impingement Syndrome / Q000175:diagnosis*; D012785:Shoulder Joint / Q000033:anatomy & histology / Q000502:physiology
keywords: Agreement; Clinical assessment; Scapular positioning; Subacromial impingement syndrome