A: What happened? You mom’s got a spring in her step today.

B: We met a colleague of mine on our way home. And guess what, my colleague said she looks young enough to be my older sister.

Note: Spring in this idiom means the act or an instance of leaping up or forward.

The idiom is often used to describe the cheerful attitude or enthusiastic positive mood as seen by the manner in which someone is walking.

This enthusiasm and attitude can be seen in the way a person has a little bounce (like a wire coil spring) as they take steps while walking.