Reproducibility and validity of a new scale “Rhombus Test” to assess dynamic balance function

Abstract

This study aimed to verify the reproducibility and validity of a new scale (Rhombus Test; RT) to assess dynamic balance function. The RT and the following physical performance indices were implemented among 144 community-dwelling elderly women: one-leg standing time, timed up and go test (TUG), 5 m fastest walking time, 30- sec chair stand test (CS-30), quadriceps muscle strength, and foot gripping force. To test the reproducibility of the RT, 60 of the participants performed the RT twiceonthesame day. The participants were divided into low, normal, and high RT score groups. The intraclass correlation coefficients were larger than 0.9, suggesting the excellent reproducibility of the RT. Moderate significant correlation coefficients ranging from ǀ0.43 ǀto ǀ0.54 ǀwere obtained between RT and three physical performance indices (TUG, 5 m fastest walking speed, and CS-30). The low RT score group demonstrated significantly poorer outcomes on various physical performance indices than did the normal and high RT score groups. These results suggest that the RT has high reproducibility and validity, and that it is an excellent indicator of decreased physical function among elderly participants. In conclusion, the RT is considered suitable for the evaluation of dynamic balance disability in the elderly.