I do think it mainly applies to short-duration, high intensity activities that are repeated in nature. Remember that the body "gets used" to certain movements and activities, so much so that the "stress" on the body becomes less over time even though higher weights are used.
Overdoing somewhat inherently catabolic activities, like marathon running and obscenely long metcons, is just too much of a load in the wrong direction on the system to recover from. Add in randomness of exercises, there is a recipe for disaster.
Adaptation implies doing something repeatedly and allowing whatever amount of "breathing room" for the system to recover.