The motion of the small foot shod in a Tartar boot embroidered with silver, and the firm pressure of the lean sinewy hand, showed that the prince still possessed the tenacious endurance and vigor of hardy old age.
He now approached the sick man with the noiseless step of one in full vigor of life, with his delicate white fingers raised from the green quilt the hand that was free, and turning sideways felt the pulse and reflected a moment.
What for people in their full vigor is an aim was for her evidently merely a pretext.
She did these things not under any external impulse as people in the full vigor of life do, when behind the purpose for which they strive that of exercising their functions remains unnoticed.
At times his brain suddenly began to work with a vigor, clearness, and depth it had never reached when he was in health, but suddenly in the midst of its work it would turn to some unexpected idea and he had not the strength to turn it back again.
There are no more uses of "vigor" in the book.
Show samples from other sources
And we ourselves assembled here today, who are still most of us in the vigor of life, have carried the work of improvement further, and have richly endowed our city with all things, so that she is sufficient for herself both in peace and war.
Thucydides -- Pericles’s Funeral Oration
A group of loudmouthed white-haired old ladies, each trying to talk over the next, a few of them texting, the kind of elderly people who have a baffling amount of energy, so much youthful vigor you had to wonder if they were trying to rub it in.