break the back of

/B R EY1 K DH AH0 B AE0 K AH0 V/
verb
  1. 1

    To complete the greater part of (a project).

    โ€œI've broken the back of painting the shed โ€“ I'll finish it after lunch.โ€

  2. 2

    To overburden (a person).

Source: https://en.wiktionary.org/wiki/break%20the%20back%20of