From Longman Dictionary of Contemporary Englishbe an effortbe an effortTRY TO DO OR GET somethingto be difficult or painful to do I was so weak that even standing up was an effort. → effort
Examples from the Corpus
be an effort• Congress's effort to ban indecent materials on the Internet comes to the court March 19.• I was so weak that even standing up was an effort.• There will be efforts at the maintenance of the house or apartment, but not much interest in improvement of housing level. 