Three-dimensional body segment kinematic data were collected (at 100 Hz) with an eight-camera, motion-capture system (Vicon MX; Oxford Metrics, Oxford, UK) as each subject walked across the laboratory and negotiated a floor-based obstacle placed in the travel path, approximately five walking steps away from where they began walking. The laboratory was illuminated with ceiling-mounted fluorescent strip lighting. The illumination over the walking area averaged 400 lux, and the luminance of the floor was 15 cd · m−2. Participants wore their own low-heeled shoes that they deemed comfortable for walking. Twenty-seven retroreflective markers (14-mm diameter) were attached directly onto either the skin or clothing at the following locations (as per Plug-In Gait software guidelines; Vicon Oxford Metrics): lateral malleoli, lateral aspects of each shank and thigh, lateral femoral condyles, anterior superior iliac spines, sacrum, medial and lateral aspects of the wrist, lateral humeral epicondyles, acromions, inferior tip of the sternum, jugular notch, spinous processes of the 7th cervical and 10th thoracic vertebrae, and the anterolateral and posterolateral aspects of the head. Markers (6-mm diameter) were also attached to each shoe, corresponding to the following locations: superior aspects of the second and fifth metatarsal heads and end of the second toe and to the upper edge of the obstacles, to determine its location within the laboratory coordinate system. Three different obstacle heights (7, 15, and 22 cm) were used. To encourage participants to use visual information to determine the position of the obstacle within the travel path rather than simply repeat a motor strategy to negotiate the obstacle, its fore–aft position was varied (i.e., blind to participant) from trial to trial by 0, 10, 20, or 30 cm. For the same reason, 15 randomly presented catch trials (i.e., no obstacle present) were also undertaken. The participants were instructed to walk at their customary walking pace to the opposite end of the laboratory, stepping over the obstacle, if present. Besides this instruction, no other specific instruction was provided. Head or gaze movements were not controlled or monitored, and participants were not asked to lead with any particular limb. Trials were completed with the participant's distance refractive correction (if worn) under binocular (Bin), nondominant eye (ND), and dominant eye (D) viewing conditions. A white patch, taped directly onto the participant's skin, was used for occlusion. A total of 87 trials [(3 heights × 3 vision conditions × 8 repetitions) + 15 catch trials] were conducted in a pseudorandom order for each participant. Data collection for each participant took approximately 2 hours, including rest periods.