I can think of two good examples you might like to look at.
The first is perhaps a toned down version of the Marine training from Full Metal Jacket
. Certainly R. Lee Ermy wouldn't get away with doing today what he did in the film, but certainly from a training and discipline aspect some of it would apply.
The other is Underwater Demolitions Training, what Richard Marcinko
went through before there were SEALS. They did a lot of swimming. A lot
of swimming. Going through mine fields with live charges set off next to them and shot at. They carried a lot of heavy logs or rafts with the instructors in them as they were hit with oars for motivation. When the trainees ran in for food and a few minutes rest the instructors would deflate the rafts then order they were pumped up by hand, until the trainees got the idea of posting guards. An old swim test involved diving into the deep end of the pool, recovering buckets of rocks, swimming as far as you can, dropping, getting air then doing back down to recover them. One guy, incidentally, walked the whole way on the bottom of the pool on account he couldn't swim, and the instructors saw that He. Would. Not. Quit
and taught him to swim.
The fifth week is the appropriatly named 'Hell Week' and the trainees are sleep deprived for five days. Back in Marcinko's time this was more of the same, and each team would be competing against each other with the losing one competing in the circus,
physical training until they quit, collapsed or died while they were constantly abused. The final test was something like a five mile swim then a five mile run in full combat gear (the outfits were twenty five pounds wet, and the instructors made sure they always were.)
Those who survive the ordeal go to SEAL heaven, a tropical paradise with unlimited alcohol, girls and explosives to play with. Here they'd do even more swimming, underwater swimming, learning what to do if there's a problem like nose bleed (forget the sharks, purge your mask,) underwater demolitions, enterprising instructors might get the trainees to build straw huts, fond hats, beer can picket fences and beer bottle wind chimes to occupy their time, and have them climb the tallest trees for the best materials. This goes back to one of the exercises in UDT that involved a row of logs. If you could make the distance from one to the other easy then the height would be next to impossible, and if the height was easy then the distance would be too far unless the trainee summoned every bit of effort he could muster.
Marcinko would take the idea of satuation training when he commanded SEAL Team Two. According to the rules the minimum jumps, dives and shooting was a pitiful amount. Marcinko would order more ammo that they burned through than the entire Marines, fifty jumps at least, constant life fire exercises through 'kill houses.' And he ordered the very best spit and polish and discipline from his men, no beards, clean offices, all equipment was to be examined and maintained at all times (before the covert nature of SEAL Team Six and Red Cell sent some of that out the window.)
If you'd like further details I have some of the Rogue Warrior
books on hand that would cover some of the training you're wondering about, but hopefully this will be of help.