The result of constant muscle tension and stiffness of joints, many of them are avoidable, and simple flexibility training can prevent these by making muscles stronger and keeping joints lubricated (润滑 ).
出自-2013年6月阅读原文
柯林斯高阶英汉双解学习词典释义
VERB
润滑；加润滑油于
If you lubricate something such as a part of a machine, you put a substance such as oil on it so that it moves smoothly.