All-out and Backbreaking

All-out adjective - Having no exceptions or restrictions.

Backbreaking and all-out are semantically related. In some cases you can use "Backbreaking" instead an adjective phrase "All-out".

Backbreaking adjective - Requiring considerable physical or mental effort.

All-out and backbreaking are semantically related. Sometimes you can replace phrase "All-out" with "Backbreaking", this terms are similar.