Inter-day reliability of the Upper Body Test for shoulder and pelvic girdle stability in adults

There are a limited number of tests for the assessment of shoulder and pelvic girdle stability. Reliable instruments are important to evaluate movement dysfunction at these joints in order to provide more objective parameters.

To evaluate the inter-day reliability of the Upper Body Test in young adults.

A reliability study was carried out with three assessments of the shoulder and pelvic girdle stability within 48-h intervals (Monday, Wednesday, and Friday). The OctoBalance® platform was used to perform the Upper Body Test in 31 active young adults (24.5±8 years). Intraclass Correlation Coefficient (ICC_2,2) two-way mixed model, Coefficient of Variation, and Bland-Altman plots were used to verify the reliability of the test. The standard error of measurement (SEM) and the minimum detectable difference (MDD_95%) were calculated for clinical applicability.

The Intraclass Correlation Coefficient ranged from 0.87 to 0.94 - Featuring a mean difference of 0.89 (95%CI=-0.19-1.97) to left and 0.95 (95%CI=-0.38-2.27) for the right side, with a low variation coefficient (3.31-5.91%) between the second and third days of assessment. There was a statistically significant difference between the first assessment day and the other test sessions. The Bland-Altman analyses revealed low bias with scores within the limits of agreement. Minimum detectable difference scores were between 4.02 and 5.10, and standard error of measurement between 1.75 and 2.72, depending on the movement side.

The Upper Body Test presented good inter-day reliability for assessing the stability of the shoulder and pelvic girdle in young active healthy adults.