2.3. Apparatus and measurements
We used sitting pressure measuring equipment (Conform-Light, Nitta Industries Corporation, Tokyo, Japan) to help establish a perpendicular model norm and used the generated pressure measurements to determine what the participants regarded as vertical (Fig. (A) The sitting pressure seat on the postural vertical. (B) Measurement of the postural vertical by means of sitting pressure.During the SPV-EO and SPV evaluation, we used an originally designed vertical board (VB). The SPV-EO and SPV measurement involved assessing the sitting level on the measuring equipment edge, with (A), a 15° or 20° slant toward the right, followed by (B), a 15° or 20° slant toward the left, moving at a speed of 1.5°/s (Fig. 