I always tell people that you've got to differentiate between passing the fitness tests and actually being "Combat fit"
If you possess a high level of GPP and good basic strength then you'll be fit and relatively injury free when faced with the demands of the job. You'll also be able to pass the tests at a pretty good level at any time and ace them with very little specific preparation.
The reverse is not true though. If you specialise on passing the tests then you may be able to do 100's of pushups but you may lack the strength to handle real life situations.
The of course there are the people who are scared of the tests because they don;t train and eat crap. Doing something like strongman training is just going to break those people!