What about a person with an athletic body?
那运动员般的身材怎么形容呢？

You can describe him or her as muscular, fit, strong, in good shape, or “ripped” – that's a slang word meaning that the person has very well-defined and visible muscles – like the guy in this photo.
你可以用muscular、fit、strong、in good shape来说，或者用“ripped”——这是俚语，意思是一个人的身材特别有型，肌肉线条明显——就像这张照片里的男人。