Beef up and Let out

Beef up verb - To increase the ability of (as a muscle) to exert physical force.

Let out and beef up are semantically related In some cases you can use "Let out" instead a verb "Beef up".

Let out verb - Express audibly; utter sounds (not necessarily words).

Beef up and let out are semantically related in longer topic. Sometimes you can use "Beef up" instead a verb "Let out".