One-leg standing test in older adults with left-right differences; does dominant foot distinctly decide?

BACKGROUND: The one leg standing test (OLST) is one of the most widely used balance function tests for assessing decline in motor function in older adults. With aging, OLST performance decreases, and difference between the left and right sides becomes more noticeable. The lower limbs have been divided into dominant and non-dominant limbs, following the example of the upper limbs. This study investigated the relationship between the dominant foot and OLST performance in older adults. METHODS: A total of 519 orthopedic outpatients participated in this study. The participants completed a self-report questionnaire (Waterloo footedness questionnaire-revised; WFQ-R) to determine the dominant foot. They also completed a locomotor functional questionnaire (Geriatric Locomotive Function Scale; GLFS-25) and were assessed for their stage of locomotive syndrome using the two-step test and standing-up test. The righting reflex was objectively investigated to determine which foot they step forward when pushed from behind. Finally, participants performed the OLST, and both standing time and left-right difference were assessed. RESULTS: Although it was difficult to unambiguously determine the dominant foot from the results of the WFQ-R, the agreement rate between simplified self-recognition and objective findings was relatively high. The locomotive grade classification showed the relation to decline of OLST, but there was no clear difference tendency between the left and right sides, regardless of age. When analyzing the decline in standing time for both legs, away from the dominant and non-dominant legs, no single leg consistently demonstrated longer standing time. Instead, the leg with the longer standing time switched at approximately the 35-36 s mark in 158 cases (30.4%). CONCLUSIONS: As motor function declines with age, OLST performance decreases, and there was a group in which the left-right difference becomes more noticeable. However, no consistent pattern was found in the magnitude of this difference. Notably, when the decline begins, the leg that takes longer to stand may shift to the other side.