youdao

Maintain the natural curve in your lower back, and keep your core muscles tight.

保持腰背部的自然弯曲，保持收紧你的核心肌肉。

youdao

Maintain the natural curve in your lower back, and keep your core muscles tight.

保持腰背部的自然弯曲，保持收紧你的核心肌肉。

youdao