I used to do PT x3 a day.
AM circuit training
Noon Swim at the base pool, and
PM would be a run either with a light ruck or a longer run
Want to use PT to develop junior personnel, have them design a PT plan for a quarter, including not just exercises but nutritional plans and metrics to record improvements. Having a Cpl leading PT for a day isn’t going to do Jack or shit for them learning leadership. It’s just another lesson, like teaching left and right turn at the halt. Putting together an actual fitness plan forces the individual to learn things about the topic, incorporating that learning into a plan that has measured effects. Thus requiring them to ensure that it is monitored and motivation given to those who aren’t progressing.
I think this speaks to the massive differences between the elements; Navy, Air force, and armoured/vehicle units need to spend their time not deployed keeping the major weapon systems working, and all the training to keep them running, which scales up in time needed based on size/complexity/impact of getting things wrong. If a vehicle breaks down, you can get out and walk. That doesn't work for ships, planes or helos, and the impact of things stopping working in transit gets significantly worse (ships will still float, planes can glide, but helos are bricks in the sky fighting gravity).
Infantry units are the weapon system, so PT, nutrition etc is all PM/CM for the weapon system, and really doesn't rely on any external so it makes sense to have something like that as the expectation.
Individual performances would improve if people were in better shape, but planes or ships with good techs can still do the mission even if they fail their force test, so when push comes to shove, the individuals get sacrificed for operations. Shortly after reconstitution RCN ops tempo went up, while staff numbers in critical trades keep falling and we are bringing on more ships that impact those same critical trades.
Because chronic understaffing and lack of resources on the 2nd/3rd line to compensate is a thing, and newer ships are going skeleton crews, if you want sailors to do infantry levels of PT you need to massively increase support when alongside so that they can fit that into their schedules. There are some departments that can, but those are generally operators so no one watching the bridge or ops room (until we get Aegis) while the ships are alongside getting things fixed. Bin rats similarly are busy at sea or alongside, and with all the parts shortages and offloading to the ships with local purchases on top of critical personnel shortages they don't get much downtime either.
At sea, a lot more people are exercising, with a lot of individual and group PT, and gyms and exercise equipment being part of the standard fit which is awesome, but it's honestly a lot harder to get any kind of routine alongside for a lot of departments, and also the same time as when you have limited windows to do things with family and friends before you sail again, so for a lot of people just makes sense to prioritise that over PT if you have to choose during limited periods in home port.
Very different as well for people in shore offices with the ship in the dock; still a lot of work needed to support that kind of thing, but a lot more structured and planned, so you can get into a good PT routine no problem. Unfortunately due to lack of techs, the RCN is looking at going to completely unmanned refits so a lot of those support to QAR jobs will go away and instead of a break, where they learn a lot supporting 3rd line and have time to do career coursing etc, people will get posted back to the meat grinder.