闪腰 is because the muscles on back are not strong.

来源: 于 2012-02-14 06:43:53 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

That is what I learned from Physical Therapist. And with some excise designed to strengthen the muscles, I am almost 100% recovered from herniated disk.