Changes in the Equilibrium of Standing on One Leg at Various Life Stages

The ability to maintain a one-leg standing position and the relation between plantar two-point discrimination and standing time on one leg were assessed. Participants were 1,241 apparently healthy people aged 2–92 years. Participants were asked to stand on one leg with eyes open (EO group) or closed (EC group) for up to 120 seconds. Coefficients of determination (COD) between subjects' ages and results for both groups were calculated by quadratic and cubic functions. The slope of the tangent line drawn against the resultant curve was calculated by a differential formula. COD for the quadratic function were 0.65 (EO) and 0.33 (EC); age at maximum values in both groups was 37 years. COD for the cubic function were 0.77 (EO) and 0.52 (EC); maximum values were at ages 30 (EO) and 28 (EC) and minimum values at ages 88 (EO) and 77 (EC). The ability to remain standing on one leg with eyes closed appears to begin deteriorating in the late 20s. Age and plantar two-point discrimination distance had a significant positive correlation, and the two-point discrimination distance and standing time on one leg had a significant negative correlation. Decreased plantar sensation appears to be related to the decline in duration of one-leg standing.