Changeability of the Rotatory Direction in the Stepping Test Caused by the Anteverted or Retroverted Posture

Abstract

　Ten healthy volunteers were spun passively on a revolving chair (0.5 Hz left-winded 7 rotation), asked to stand up immediately thereafter and take 30 steps with their eyes closed. The observations revealed that subjects having an anteverted posture turned to the right, whereas those with a retroverted posture turned to the left. To ascertain the reason for this directional switch, volunteers carried a 10-kg weight on their front or back while keeping their axis vertical. The front-weighted subjects turned to the right like the subjects with the anteverted posture, while the back-weighted subjects turned to the left like those with the retroverted posture. The results indicated that shifting of the center of gravity, and not the posture, was the reason for the difference. When the subjects kept their arms up forward horizontally and the legs high up as in Fukuda's stepping test, they turned to the right, because their horizontal arms and highly up legs set the weight forward. The neutral pose, with the arms hanging down along the side of the body and stepping low, was scarcely associated with any turning.