Why Muscles Shake During a Tough Workout

MY FITNESS PAL—You’ve probably felt your muscles shake at some point during a hard workout. At first, it can be alarming — you’re literally vibrating like a bell that’s ringing for you to halt whatever it is that you’re doing.
You might wonder: Is it normal for my muscles to momentarily quiver out of control while holding this plank? Is my infrastructure in danger of collapse?

The short answer is no, you’re good.

While you may crumple to the mat, you’re likely not destroying your foundation but rather reinforcing it. That little muscle quake is generally a good sign that you’re pushing yourself and getting stronger for it.

Read the full article on My Fitness Pal!