Strong = 强壮 [Qiáng zhuàng]
A small boy holds a grown man straight up over his head with one hand, like a weightlifter. That is 强壮.
强壮 (qiángzhuàng) means “strong,” physically strong and sturdy. 强 means strong or powerful, and 壮 means robust.
强 on its own often describes ability: 他的能力很强 (tā de nénglì hěn qiáng), he is very capable.
他的身体很强壮。 — Tā de shēntǐ hěn qiángzhuàng. — He is very strong.
多运动，身体会更强壮。 — Duō yùndòng, shēntǐ huì gèng qiángzhuàng. — Exercise more and you’ll get stronger.