We have two basic types of muscle fibers, slow twitch and fast twitch.

我们每个人有两种基本的肌肉纤维，慢抽搐和快抽搐肌纤维。

youdao

Too much distance work can convert fast twitch muscle fibres into slow twitch fibres and can actually decrease an athlete's speed over time.

太多的长途运动会造成快肌纤维转换成慢肌纤维，并随着时间的推移，逐渐减慢运动员的速度。

youdao

As noted, we lose muscle mass with age. Especially quick to deteriorate are fast-twitch muscle fibers, which power quick, explosive movements.

如上而言，随着年纪的增大我们的肌肉会失去力量，尤其是快速收缩的肌肉纤维更为明显，这部分纤维让我们跑得快，启动有爆发力。

youdao

Or the gene that produces more fast twitch muscle fiber and has been found in all Olympic sprinters.

FORBES: Nike Dumps Lance: But Who's Lying Now?

Part of me missed the fast twitch, addictive nature of being plugged in, however another part of me appreciated the time to take a deep breath and consciously focus on being in a particular moment in time.

FORBES: A Bold New E-Commerce Experience: Going Where No One Has Gone Before