Intrarater reliability of inclinometer scapular upward rotation measures was determined over a two-week period among unimpaired females prior to a larger study on women with breast cancer.
A measurement-focused study was performed at a university laboratory. Following institutional review board approval, a convenience sample of 15 unimpaired females were recruited. Measures were taken 3 times at each position (0°, 90°, and 120° of glenohumeral elevation) during two sessions that were two weeks apart. The position order for testing was randomized and the rater was blinded to actual degree numbers. Interclass correlation coefficients [ICC (3,k)] and standard error of the measure (SEM) assessed reliability with probability at P ≤ .05 (two tailed) for significance and a test value of .90.
Overall agreement was significant (ICC = .953; P < .001) with an SEM of ± 4.42°. Secondary analysis by position found significant agreement at 120° (ICC = .968; P = .001); but not at 0° (ICC = .908; P = .416) or at 90° (ICC = .892; P = .567). SEM by position were: ± 2.02° (0°), ± 4.73° (90°), and ± 5.63 (120°). Limitations are the small sample and inability to generalize results to multiple raters or clinical populations.
Results suggest good overall intrarater test-retest reliability for research and values are provided for SEM as a relative index for reliability. Further study is required by using a larger sample to confirm study results and to generalize findings to the breast cancer population.