stretch (one's) legs
To stand or walk to help relieve stiffness in one's legs, usually from sitting for a prolonged period of time. Let's stop off at this rest area for a while. After three hours of driving, I'm sure everyone would like to stretch their legs a bit.
stretch one's legs
Fig. to walk around and loosen one's leg muscles after sitting down or lying down for a time. We wanted to stretch our legs during intermission. After sitting in the car all day, the travelers decided to stretch their legs.
stretch (one's) legs
To go for a walk, especially after a lengthy period of sitting.
stretch one's legs, to
To stand up or go for a walk in order to relieve muscular stiffness or for the exercise. This term has been around since the seventeenth century. Izaak Walton used it in The Compleat Angler (1653): “I have stretch’d my legs up Tottenham Hill to overtake you.”