Figure 1. The force plate signals in relation to the step cycle.

Top, schematic illustration of the infant at three instances in the step cycle. Note that the infant was placed on the treadmill, at the junction between the front and the rear force plate. Bottom, the corresponding force plate (FP) signals are shown with the three instances in time indicated by the vertical dashed lines. The letters L and R under the front plate signal indicate the time of left and right foot contact, respectively. The L and R under the rear force plate indicate the time each foot slides onto the rear force plate. A, the right foot has made contact with the front force plate (note the corresponding rise in front force plate signal). The left leg is in late stance and its force is registered by the rear force plate (note the fall in rear force plate signal). B, the right leg is in the mid-stance phase. The force of the right leg is registered by the front and rear force plates (see the fall in front force plate signal and the rise in rear force plate signal). Meanwhile, the left foot is in swing phase, and does not contribute to any of the force plate signals. C, the right leg is in late stance and its force is registered by the rear force plate (see the fall in rear force plate signal). The left foot has made contact with the front force plate, causing a rise in the front force plate signal.