Figure 3.

Aerial view of the 1-km outdoor walking course, including ground inclines, declines, and stairs. Four of the participants started near the edge of the grass and walked a lap according to the figure shown. They then turned around and walked the same course in the opposite direction. The remaining five participants walked the course in the opposite direction (5 to 8, then 1 to 4). The ground incline data when traversing the course in clockwise direction is shown in the bottom trace. Stairs, shown in broken lines (top) or hidden (bottom), were excluded from the analysis due to faulty data and behavioral variability.