Try to go as low as you can and then bounce up.

尝试尽可能的低，然后再反弹上去。

Even though, the boy liked to bounce up and down.

尽管如此，男孩还是喜欢上下弹跳。

If rock was held down, formerly, it can bounce up.

之前，如果岩石掉落，可以弹跳起来；

The head should not bounce up and down during this drill.

在做这个训练的时候，头部不允许上下移动。

Patient: Why do you ask me to bounce up and down on my bed?

病人：为什么你让我在床上上下蹦跳呢？