In the military, a fall-out is someone who lags behind his unit formation. This is most often associated with unit runs, such as the Battalion run. A fall-out will be encouraged or antagonized by members of his unit to catch up and remain in formation, most often because there is incentive for remaining together. A person is usually considered a fall-out when he stops trying to maintain pace, falls behind too far to catch up, or is out of formation at the end of a run.