Wiktionary
vb. (context intransitive English) to interfere, or intrude forcibly
Usage examples of "muscle in".
He immediately put his mind to the few progressives available to him: the relaxation of every muscle in his face, head, and neck.
A muscle in his thigh jumped and he moved his leg to ease the cramp.
May you never move a muscle in your life, until you lose someone you love as much as I loved her!
The kid was good, too good--he had it all, right down to the screaming tension radiating from every muscle in his body.
A muscle in her cheek twitched, as if she realized that remark might be thought to harass the former Amyrlin and Keeper, and she seized Areina and Nicola each by an arm.
The kid was good, too goodhe had it all, right down to the screaming tension radiating from every muscle in his body.
The kid was good, too good -- he had it all, right down to the screaming tension radiating from every muscle in his body.