--you probably could put the pads on Alan's foot tops, provided it was on a low setting.

There's a considerable amount of trial and error involved in finding the best places to put the pads, the best wave form to use, and the best intensity level. Even small shifts in pad position, with the wave form/intestity remaining the same, produces different sensations in different places.

The pads that I use have the conductive gel on them, in order to allow for the current to make a circuit--normal skin is actually somewhat resistant to current, so this helps. It's also why one uses the pads at least two at a time in an area (in different places)--to make a circuit that (hopefully) includes the region you want to target.

The general principle is that the electrical impulses coming from the unit interfere with the slower pain impulses that come from the small-fiber nerves, but there also seems to be some evidence that usage over time can re-ccordinate the nerve firing pattern in an area and therefore reduce the pain long-term. (Pain is often thought to be maintained in an area by patterns of neural firing that get triggered more easily the more they are elicited, to the point that normal non-painful stimuli trigger them, resulting in allodynia--TENS and inferential therapy units, as well as the Rebuilder, work on the theory that one can "re-train" the neural circuits and make them more likely to fire in less painful patterns, if one makes them fire in these patterns often enough.)