break your back doing something/to do something
break (one's) back
To put forth a great deal of effort. I've been breaking my back trying to get a passing grade this semester, so failing by two measly points is incredibly frustrating. Don't break your back trying to please these people—they'll never appreciate it.
In tennis, to win a game immediately after losing the previous game as the server. The tennis star broke back seven times after losing serve during the tournament.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
break one's back
(to do something) Go to break one's neck (to do something).
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
break your back
If you break your back to do something, you work extremely hard to try to do it. When you're breaking your back to make a business work, it's going to cut into your time with family. `I had been travelling all over the country, breaking my back just to get a job,' she says.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012
break your ˈback doing something/to do somethingwork very hard to achieve something: I’ve been breaking my back to sell as many books as I can. ▶ ˈback-breaking adj. (of physical work) very hard and tiring
Farlex Partner Idioms Dictionary © Farlex 2017