Intraobserver Reliability of Angular and Linear Measurements of Scapular Position in Subjects With and Without Symptoms

Lewis JS, Valentine RE. Intraobserver reliability of angular and linear measurements of scapular position in subjects with and without symptoms.ObjectiveTo assess intraobserver reliability of angular and linear clinical measurements of scapular position.DesignTest-retest analyses.SettingOutpatient department in National Health Service teaching hospital in the United Kingdom.ParticipantsSubjects (n=45) without symptoms (21 men, 24 women; age range, 23–56y) and 45 subjects (22 men, 23 women; age range, 19–84y) with shoulder symptoms (defined as pain in the C5-6 dermatome reproduced by shoulder movement and not reproduced with cervical movement).InterventionsNot applicable.Main Outcome MeasuresIntraclass correlation coefficient (ICC) models 2,1 and 2,3, 95% confidence intervals (CIs), and SE of measurements for 68% confidence and 2 SEs of measurement (for the 95% CI) for the bilateral angular measurements of scapular rotation and tilt, and the bilateral linear measurements of lateral scapular displacement (protraction) and vertical displacement (elevation).ResultsFor subjects without symptoms, ICC2,3 results ranged from .75 to .98. The 2 SE results for the angular movements ranged from 1.8° to 2.4° and from 0.4 to 1.0cm for the direct linear measurements. Subjects with symptoms: ICC2,3 results ranged from .61 to .98. The 2 SE results for the angular movements ranged from 1.4° to 2° and from 0.6 to 1cm for the direct linear measurements.ConclusionsRepeated-measure (ICC2,3) results were more reliable than single-measure (ICC2,1) results. Very good to excellent intraobserver reliability was demonstrated for the angular and linear measurements of interest in both shoulders of subjects with and without symptoms. The 2 SE results provide guidance about the error associated with the individual measurements and will assist the clinician determining whether a change in the static position of the scapula has occurred as a result of intervention or over time. (National Research Register identifier N0060148286.)