Wiktionary
strong as an ox
a. (context simile English) Very strong and powerful
Usage examples of "strong as an ox".
I was always tall for my age and the Gods had made me strong as an ox and I ascribed my victory to their honour even though Hywel whipped me for it.
For all her shortish stature and broad, dumpy appearance, the woman was strong as an ox and could on occasion move as fast as greased lightning.
He was strong as an ox and would now be only forty-two years of age.