 All the health experts are trying to coerce us into getting more exercise, and I guess they're right, both in terms of health and etymology. Exercise earlier referred to military exercises, coming from Latin exarchitium, training exercise of soldiers, but before that it's believed to have referred to the driving of draft animals as it is made up of x, out, plus arcara, to prevent enclose, so literally remove restraint. Arcara comes from the Proto-Indo-European root arc, hold, contain, guard, which also leads to the words arc and arcane, and when arcara was combined with the prefix calm together, it produced coercara, to control restraint, which came into English as coerce, originally meaning to restrain by force of law, before shifting to its modern sense.