There is a new way to exercise and condition your body in the great outdoors which has been gaining popularity over the last couple of years. You may be a veteran of it, or completely unfamiliar with the term, depending on the circles in which you play. It's called rucking, a term that derives from the military slang for a rucksack (aka backpack). To ruck is also a verb meaning to move with a rucksack (usually with a significant amount of gear), and implies action, energy, and purpose.