She is not very young. She is no spring chicken.

VOA: special.2010.06.13

If you connect the body to a spring, which is neither compressed nor extended, there's no force acting on it.

如果将一个弹簧连在这个物体上,弹簧既没有被压缩也没有被拉伸,也不会有力作用在它上面

耶鲁公开课 - 基础物理课程节选