As a now partly crippled veteran of RAF PTI's and physio's whose attitude was and I quote directly "the reason you have a bad back is because you are too fat." at the time of my injury/downgrading I was 15 and a half stone still cycling over 100 miles per week, swimming, cycling to work, going down the gym and doing as much surfing and sailing the Moray Firth would allow, all was in my own time. I used to surf before work, during lunch and after work, all my phis was geared towards my sports. When i discussed the fit for purpose with the pt muppets their attitude was you fat, you unfit end of discussion. They never did take me up on an offer to go for a surf with me at Thurso when it was double overhead barrels with snow on the beach.
You have to identify your aims for fitness, give the troops time and incentive to do it and make allowances that tg1 and 2 work more hours than the shiny arses know exist in a day and to give them time for sport is a luxury they don't have. I know, we could get all the engineers running laps round the HAS site between the waves!!! don't worry about the backstacked repairs or servicings.
I never saw a liney quit or fall over before the jet was done.