Idiom - Out of Shape

It means not in a good physical shape. It is used when a person can't do any physical activity with eficiency, like running, walking, swimming, aerobics, or any other physical activity. This person gest sofocated and says, "I'm out of shape". It also applys when something doesn't work propertly, it can be said, "It is aout of shape."

Examples: a) The studens couldn't keep up their pase in the walk-a-thon. They
are out of shape.
b) I got so tired after swimmming practice. I think I'm out of shape.