I just did a search on The batman images and pretty much every cartoon image that came up was not 'swimmer' stature but body builder type (schwarzeneggeresque) type builds, except for the Adam West portrayal. This included the old Justice league Cartoon, the Frank Miller Batman, the Old Detective Comics Batman and most of the actual Comic Book portrayals.
I am not talking Bane level big, but not 'Sleek' by any stretch of the imagination. For instance, if you were to compare The Flash to The Batman, Bats is absolutely bulkier by a considerable margin. Not having super powers, he still had to hit as hard as the Super Powered bunch, so he really bulked up.
And then if you look at The Frank Miller Batman and he is a real bruiser.