Intrarater and Interrater Reliability of an Adapted Sphygmomanometer on Isometric Abdominal Muscle Strength

Purpose: To evaluate the intrarater and interrater reliability of an adapted sphygmomanometer on isometric abdominal strength. Subjects: The subject sample consisted of 9 randomly selected raters from 23 second year physical therapy students that volunteered for the study. Methods: Each rater performed three abdominal muscle break tests on each student subject using the adapted sphygmomanometer. The student subjects were positioned in the hook-lying position on a wedge pillow with knees flexed at 90°. The subject was asked to perform a partial sit-up to the point where the inferior border of the scapula was off the wedge pillow. With the sphygmomanometer placed just below the supra sternal notch, the rater then performed an abdominal muscle break test to the point where the spine of the scapula made contact with the wedge pillow. Results: The analysis of variance (ANOVA) results were used to calculate intraclass correlation coefficients (ICC). Low intrarater and interrater correlation coefficients were found for both (r= -0.015 and r= -0.05) respectively. Results indicate that observed differences are attributed to measurement error. Conclusion: The use of an adapted sphygmomanometer was found to be unreliable on a healthy sample for intrarater and interrater reliability. The results suggest that observed differences between raters are attributed to either rater strength differences or experimental error