This graph shows two data sets: swimspeed data in meters per second, and relative tail acceleration in counts / 16th of a second, for a dive segment of about three minutes. The tailstroke data shows the animal doing three to five vigorous strokes, during which times it typically accelerates from less than two to almost three meters per second swimspeed over maybe 5 to 8 seconds. This stroking is alternated with periods of non-stroking during which the speed gradually reduces back to less than two meters per second.