Doctor Who: The Workout Plan

Just finished a great workout on the elliptical machine while listening to the second half of The Fearmonger. I've been trying to up the intensity of my workout by doing short sprints at running speed. During the later part of my workout, I had the fun idea to time these sprints to parts of the story where the characters were actually running. (To the extent possible - I don't think I'm quite fit enough to be a Doctor Who companion. Though at least I wear sensible shoes.)

Which got me to wondering: if you were following the "run when the Doctor or companion is running" rule, which story (audio or TV) would provide the best workout?