Fig. 9. Representative traces for force, impulse and power from large-amplitude elongated body theory (EBT; in black) and particle image velocimetry (PIV; in red and green). Each black line shows force and power for a single tail beat. A total of 14 tail beats from a single swimming bout are shown. (A) Force (left axis) and impulse (right axis) over a tail-beat cycle. Because impulse is force integrated over time, impulses are indicated as lines, showing the impulse value and the time over which it was integrated. (B) Power from EBT and PIV over a tail-beat cycle. PIV values have standard error in a lighter color around the trace. The total power measured through PIV is shown in green, and the `lateral' power, measured using only the lateral velocity component, is shown in red.