break your back

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.
See also: back, break

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.
See also: back, break

break your ˈback doing something/to do something

work 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
See also: back, break, something