tensing

Most methods of snake locomotion involve some pattern of curling up and straightening out again, such as concertina movement, scrunching their tails up toward their heads and pushing out headfirst, or lateral undulation, tensing and flexing alternating muscles in a sort of continuous wiggle.

"Sometimes, I catch myself tensing up," Justin said.

I point and flex my foot, stretching and tensing through my entire leg as much as I can.

A grim Donald J. Trump leaned back from the defendant’s table inside a jammed 13th-floor courtroom in Miami on Tuesday, jaw set, arms crossed, his back muscles tensing visibly under his dark suit jacket.

A grim Donald J. Trump leaned back from the defendant’s table inside a jammed 13th-floor courtroom in Miami on Tuesday, jaw set, arms crossed, his back muscles tensing visibly under his dark suit jacket.