Definition of "exertion"

Again she felt a return of that utter despondency which had fallen upon her after Guido's death: but then she could indulge in it unmolested, and that was something of relief: now she was forced into exertion, that sort of exertion of all the most tiresome, because the least interesting...

1834, L[etitia] E[lizabeth] L[andon], chapter XXX, in Francesca Carrara. […], volume III, London: Richard Bentley, […], (successor to Henry Colburn), page 246

Liverpool have looked a little jaded from their exertions in recent weeks and there was an air of desperation about their attempts to restore equality in the closing minutes in the face of the experience and game management of opponents who are time-served masters of the Champions League art.

2022 May 28, Phil McCulty, “Liverpool 0-1 Real Madrid”, in BBC Sport