thank you James ^_^

A good example would be an athlete such as a boxer that hasn't been training recently. Because of this, he would be slower, less strong, fatter and have less stamina than he would have if he was in peak physical condition. So you could say that he was out of shape. Comparatively, at least. But this phrase is commonly used for average people that have a little fat on their body, don't have much stamina, etc.

Actually, "less than optimum physical condition" would be a better way to express this instead of just "poor physical condition". It doesn't imply terrible health. It just implies a physical condition that is less than ideal.

Usually this refers to someone's poor physical condition. This is often due to lack of exercise and poor diet. Although this phrase can also be used in other ways with different meanings. But these other uses of these words are usually when "out of shape" is part of the larger phrase "bent out of shape".