Reliability and Validity of the Conditional Functional Reach Test for Healthy Adults

Abstract

[Purpose] The purpose of this study was to clarify the relationships between the Functional Reach Test (FRT) and the modified Functional Reach Test under restricted hip joint mobility (modified FRT), and the forward displacement of the center of pressure (COP-A), as well as to examine the reliability and validity of both tests. [Participants and Methods] The participants were 22 healthy adults without motor disorders. The evaluation items were the standard FRT and a modified FRT performed with the hip joint degree of freedom restricted by placing an adapter table against the buttocks. Under both test conditions, the reach distance (FR distance) and COP-A were measured. [Results] Compared to the standard FRT, the modified FRT demonstrated high reliability, with an intraclass correlation coefficient of 0.97 across three trials. In addition, a strong correlation (r=0.73) was observed with COP-A. [Conclusion] The modified FRT showed high reliability and validity of measurement. These findings suggest that the modified FRT is useful as an objective index for quantitatively evaluating the balance ability of healthy individuals.