warm-up

Exercising in preparation for strenuous activity.

Performing mild exercises to prepare for some more strenuous activity.

“the singers have to warm up”

“the marathon runner did not warm up and hurt himself”

Make one's body limber or suppler by stretching, as if to prepare for strenuous physical activity.

Get warm or warmer.

Become more friendly or open.

Cause to do preliminary exercises so as to stretch the muscles.

Run until the normal working temperature is reached.