Umeå University's logo

Background: The tibialis posterior muscle has an important role both in stabilizing the foot and in inversion, plantar flexion, and adduction of the foot. Impaired function can lead to tibialis posterior dysfunction. A clinical test that can objectively measure tibialis posterior strength is warranted.

Objectives: The aim of this study was to investigate the interrater, test-retest, and intersession reliability of a test designed to measure tibialis posterior strength with a hand-held dynamometer.

Design: Interrater, between-day test-retest and intersession reliability.

Setting: University laboratory.

Participants: The participants comprised 20 healthy individuals (mean age 28.8 years, n = 10 women) without foot problems.

Method: A test was designed to test tibialis posterior strength with a hand-held dynamometer (HHD). The test was performed on two occasions 5–15 days apart and was carried out by two raters. The intraclass correlation coefficient (ICC), 95 % confidence interval, standard error of measurement (SEM), and minimal detectable change were calculated.

Results: Interrater reliability was good on both occasions (ICC: 0.769, 0.794), test-retest reliability was moderate for both raters (ICC: 0.671, 0.672), and intersession reliability was excellent (ICC: 0.934–0.967). However, the confidence interval had a large variation (-0.027–0.986) and the SEM was relatively high (2.356–3.863 N).

Conclusions: This test seems to be reliable, but has some limitations. The results suggest that the current version of the test could be used to compare strength between feet, but that further development of the test is needed to achieve increased interrater and test-retest reliability.