You might be interested in some threads from the FAQ section on "Did people in the past exercise/work out/lift weights?":

• How strong/muscular were ancient warriors? Did they know enough about muscle growth to be the same build as many athletes/bodybuilders now? When did humans start becoming adept at bodybuilding? - 85 comments, over 1 year old.
• The topmost top comment is a history of modern bodybuilding, but the second top-level comment is a direct commentary on the fitness of Greek soldiers during the Greco-Persian Wars.
• Did spartan warriors "work out" in the sense that athletes do today? What did they do? - 67 comments, over 2 years old.
• The commenters here discuss the questionable accuracy of the primary sources for this matter and one commenter gives a breakdown of one primary source's comments on Spartan athleticism and training.