(a) component x
  a b  c R2
Romberg's posture 0.62 -0.08 -5.55 0.89
Posture I 0.95 -0.08 -5.64 0.94
Posture II 2.02 -0.31 -5.32 0.87
(b) component y
  a b  c R2
Romberg's posture 0.78 -0.05 -5.61 0.91
Posture I 0.84 -0.1 -5.65 0.94
Posture II 1.02 -0.22 -5.69 0.96
Table 2: Coefficients of the potential function in each component: (a) lateral direction x, and (b) anterior/posterior direction, while subject’s eyes were closed.