Walking is periodic too: dancers and gait researchers alike call its frequency cadence — steps per minute. A relaxed walk sits around 100-120 steps/min, roughly 1.7-2 Hz.

But cadence alone doesn't tell you how fast someone is actually travelling. A tall person and a short person can share the same cadence and still cover very different distances per step.

Which raises the question underneath this whole session: if frequency alone isn't speed, what else is needed?