Fig. 2. Overhead view of experimental set-up. Circular lines of 1, 2, 3, 4 and 6 m radius were painted on the ground such that they were all cotangential with a force platform mounted flush with the ground (counter-clockwise sprinting direction, as indicated). We used a 30 m straight runway leading up to the force platform for control trials. A high-speed video camera recorded lateral views of the subjects as they stepped onto the force platform. Pipe sleeves (gray circles) were inserted into the ground to mount a removable steel pole at the center of each track for tethered trials.