'Vigorous' in the Bible

Whenever the more vigorous of the flock came into heat, Jacob would place the branches in the troughs in front of the flock to make them mate by the branches.

Moses was 120 years old when he died. His eyesight wasn't impaired and he was still vigorous and strong.

After this, King Sennacherib of Assyria sent his messengers to Jerusalem while he was in the middle of a vigorous attack on Lachish. They delivered this message to King Hezekiah of Judah and to all the people of Judah who had gathered in Jerusalem:

Dear friends, although I was eager to write to you about the salvation we share, I found it necessary to write to you and urge you to continue your vigorous defense of the faith that was passed down to the saints once and for all.