"Physical exertion" refers to the physical effort or energy expended in doing an activity or task that requires physical strength or movement. Full definition
I recall switching to Sex and the City 2 at this point — and making it to end, surely a feat of physical exertion unmatched by any living human being, at least one at 40,000 feet in the air. (theexpeditioner.com)
It was developed to support the body's muscle recovery after physical exertion like biking, running, sports competition and gym workouts. (drinkorganicfuel.com)
Following digestion, BCAAs are circulated in the body and used as a quick source of energy during physical exertion. (ora.organic)