Doing the job is fine but how do you decide if somebody is fit to do it?
One persons job in the same trade can be vastly different to the next persons!
The crux is it's part of the job and has been for a very long time, not liking it or it's testing methods does not matter. I am no "gym queen" but simply recognise the need for a healthy body to aid me in my daily life. The RAF wants you to do likewise and employs fair and world wide recognised methods of testing.
Personally I would introduce mandatory pt three times a week to ensure my workforce maintained it's health, that really would help save the need for tranche three!
You would lose some very capable people but you would keep just as many fit capable ones instead.
Am off for a run, enjoy your surfin.