Figure 1.
Schematic of the experimental set-up and how foot placement and heel clearance parameters were determined.
a) The three visual conditions: i) no visual occlusion, ii) lower visual field occlusion from penultimate step heel contact iii) lower visual field occlusion from final step heel contact, and b) foot placement and heel clearance parameters.
Figure 2.
Group mean (±SE) peak amount of head-flexion (deg) occurring during the penultimate and final steps before the kerb-edge, step on to lower level and at instant of ground contact.
Table 1.
Group mean (±1 SD) kinematic measures for the full vision and lvf occlusion conditions: a) measure occurring during approach, b) measures occurring during the step on to floor, and c) measures occurring during landing.
Figure 3.
Lower visual field influence upon heel trajectory.
Trajectories of the heel marker are shown for all trials from one subject for the step onto the lower floor level. Trajectories are plotted from lead-limb toe-off up to instant of contact with the lower level. NB, the heel trajectory for the condition when lvf was occluded at instant of penultimate step contact onwards, was beyond or towards the upper part (indicating higher heel clearance) of the variability boundaries of the full vision available throughout condition.
Table 2.
Group mean (±1 SD) temporal parameters for the full vision and lvf occlusion conditions.
Figure 4.
The three visual conditions.