Figure 3.

Definition of the thigh angle for the 30-s CST. It is defined as the angle between the subject’s thigh and a horizontal plane perpendicular to gravity (e.g., the seat of the chair). It is depicted as the angle (alfa) between the red line along the longitudinal direction of the subject’s thigh and the red line on the seat of the chair; therefore, (a) the expected value of the thigh angle in the sitting position is 0; (b) the value of the thigh angle at any time during SiSt and StSi transitions is bigger than 0 and lower than 90°; and (c) the expected value of the thigh angle in the upright position is 90°.