Her legs had weakened, and she joked that she felt like she was three years old again, relearning the whole process of walking.

她的腿变得很虚弱，她开玩笑说感觉自己又回到了3岁，重新学习走路的整个过程。

youdao

Another miner, Mohan Soren, has an eight-year-old daughter whose legs became paralyzed three months after she was born.

CNN: NUCLEAR FALLOUT

At about three weeks old the chicks were mature enough to band, because their legs won't grow any more, but too young to fly away.

WSJ: 4 falcon chicks living on NY-NJ bridge are banded