Abstract: An electronic device particularly useful as a jogging computer comprises presetting means for presetting the size of the user's step, an inertia sensor sensing each step, a central clock, and a microprocessor computing the user's speed and distance travelled, and displaying same on an electronic display. The described device further includes a pacer which produces a tone at a preselected rate to aid the jogger in pacing himself. A second embodiment of the invention is described for attachment to a bicycle for measuring speed and distance travelled of the bicycle.