Reliability and concurrent validity of a modified timed up and go test for healthy preschoolers.

The purpose of this study was to assess the interrater and test-retest reliability and the concurrent validity of the modified timed up and go test for preschoolers. As such, we aim to determine the most suited outcome of the modified timed up and go test: the best or the average performance. Thirty-two children (age 3-5) performed three timed up and go test trials as fast as possible on two separate occasions. During the first session, two researchers recorded the time to perform the task simultaneously. For reliability analyses, intra-class correlation coefficients (ICCs) and the minimal detectable change were determined. A Pearson correlation coefficient was calculated to determine concurrent validity between the timed up and go test and the balance subscale of the Movement Assessment Battery for Children, 2nd edition. Interrater (ICC > 0.97) and test-retest (ICC > 0.75) reliability were good both for the average and the best timed up and go test performance. A minimal detectable change of 1.86 s was found for the best performance, and 2.30 s for the average performance. Only the best timed up and go test performance correlated significantly with the balance subscale of the Movement Assessment Battery for Children, 2nd edition, though fair (r = -0.347, p = 0.007).Conclusion: The modified timed up and go test for preschoolers using the best performance is reliable and recommended to reduce standard and measurement error. What is Known: • A large variety of timed up and go test protocols is available for children • The protocols differ in the instructions on walking speed (self-selected/fastest), the use of an extra motivation (e.g., touch a star on the wall) and the applied outcome (average/best performance) What is New: • The best timed up and go test performance induces more consistent test results between raters and sessions and also less standard and measurement error in 3- to 5-year-old children • The best timed up and go test performance should be preferred over the average performance to achieve both reliable and valid test results in 3- to 5-year-old children.