Sit-ups are actually not that good for you, but seeing as how we do sit-ups quite frequently in the Army, I figured I'd do them regardless.
The 600 push ups is a great goal! But I just want to offer this bit of advice.
A key aspect of working out is intensity, and though 600 push ups is an excellent workout, doing them over a spread of 10 hours isn't that beneficial. Unless of course, you're doing some sort of other workout in between each set of push ups.
That's just what I think though! You know your body much much better than I do.
