limber up

verb4

1. •
   To stretch one's muscles to make them more limber, usually as a preparation for physical exercise.

   • The swimmer limbered up for a few minutes before the final.
2. •
   To make (someone or something) more limber or flexible.

   • You need to limber up your wits before the exam.
   • A good massage will limber up the neck and arms.
3. •
   (figurative) To prepare; to make oneself ready.
4. •
   To attach a limber.