Would you confirm that the expressions below have only ONE meaning in which they are freely interchangeable:
at a stretch
on the stretch
at a stretch - 1. continuously; without interruption: It was impossible to work for more than an hour or so at a stretch.
2. by making a special effort; by stretching one's resources: We have provided food for only fifty people, but we might be able to make it do for sixty at a stretch.
on the stretch - 1. tightened and extended: The mariner has favorable gales which keep the sails on the stretch.
2. = at a stretch 1: He tells me that the Finns recite their poems six or seven hours on the stretch, spelling one another, as we say in New England.
3. (coll.) using exaggerated statements: He's always on the stretch... He never tells the truth except by mistake.
4. in the state of tension: The inmates of Sisera's harem are on the stretch of expectation for the sight of their champion.
5. (also: at full stretch) working to the utmost of one's powers: Me and my stoker were on the stretch all the time, doing two things at once - attending to the engine and looking out.