All participants demonstrated adequate performance for the test with results ranging from 20/10 to 20/50 for the left and right eyes. Six participants used glasses or contact lenses for visual acuity correction. Experimental task The experimental task consisted of standing quietly on bilateral force plate (Neurocom International Inc., Oregon, USA) in front of a 91×122 cm flat screen and viewing a target presented on this screen (Fig. 1). The screen was placed at 1-m distance from the participant’s Inhibitors,research,lifescience,medical eyes. The target was the computer-generated character “Mia”

standing in T-stance (upright with arms stretched out to the side). The character was created with the use of Autodesk MotionBuilder 7.0 software. Figure 1 Participant standing in front of the screen and looking at the target presented at +25° gaze angle. In baseline trials (0°), the character was presented so that the cross find more formed by her arms and body in T-stance was at the participant’s eye level.

In other trials, the character was presented in a randomized order in a manner that required the participant Inhibitors,research,lifescience,medical to alter gaze angle, or viewing angle or both (Fig. 2). To change a gaze angle, the character was shifted vertically up or down on the screen (to create gaze angles of approximately +25° or −25° above and below eye level), while keeping the visual image constant. The viewing angle was manipulated by rotating the figure, Inhibitors,research,lifescience,medical thereby altering the character’s apparent vertical body orientation, while maintaining its location in the middle of the screen (Fig. 2B). The character was presented as if leaning toward the participant Inhibitors,research,lifescience,medical (+25°) or away from the participant (−25°). In other trials, the character changed both position on the screen and vertical orientation simultaneously (gaze and viewing angle +25° or −25°), thereby creating

a naturalistic visual perspective similar to the real-world situation of looking at a person from above or below. In addition to Inhibitors,research,lifescience,medical the character-manipulation, a set of trials was done without a character, and participants were asked to stand quietly looking at the gray screen in front of them. Figure 2 The target character “Mia” presented at 0° (left panel) and +25° (right panel) viewing angles. Participants were asked to watch the character body without moving their head during the different experimental gaze and viewing angle conditions. Physiologically, viewing a target deviated from European Heart Journal the eye level up to 25° does not require head movements. Each trial lasted 10 seconds and was repeated three times in each of the eight conditions for a total number of 24 trials. Data collection and analysis Kinetic data from the bilateral force plate were collected, and the parameters of center of gravity (COG) displacement were analyzed. These parameters included the amplitude of the COG sagittal displacement, the surface area of the COG excursion, and maximum forward and backward angular displacements of the COG.