Press-ups, crossed-thumb press-ups, wide-arm press-ups, sit-ups, twist sit-ups, leg raises, step-ups, step-throughs, hill sprints, rope climbs, ladder climbs, wall climbs, crunches, sprints, runs, long runs, long mixtures of running and sprinting, loaded marches, loaded runs, loaded hill-sprints, lots of marching, lots of running, lots of press-ups, more press-ups, a tiny bit of swimming, more running, an occasional tour of the assault course, some brutal circuit training, squat-thrusts, star-jumps, a sod of a thing that starts in the press-up "down" position and goes via squat to star-jump and back, obstacle courses and the fireman's lift (bloody rugby players!) plus some running and press-ups ...
... and then the exercises. An exercise is like an operation, but scripted and less likely to result in death or serious injury because the enemy are only playing the part. Digging your new home and filling it back in is harder for some than for others. Patrolling's fine as long as nothing's happening. The leopard crawl will wear on your elbows and knees (I've seen blood) and is exhausting. The kitten crawl will wear on your nerves in the middle of the night with more people hunting you than there are other people for them to find instead. The real sweat there comes from FIBUA (Fighting In Built-Up Area, also known as FISCH: Fighting In Some ****'s House) and fire-and-manoeuvre.
For FIBUA, imagine the last battle in Saving Private Ryan without the tanks. Within thirty seconds nobody knows where anybody else is or what the hell's giong on except that all bloody hell is breaking loose everywhere around you. There is a lot of screaming back and forth to try to keep people in touch and let everyone keep track of what's going on, and then something comes in through the window and you all GTFO fast and then there are these weird little glowy things drifting along the floor, giving off funny-coloured smoke, and you suddenly realise you're in the coal cellar, the back garden, the khazi, the kitchen cupboard or wherever you landed with no clue who's on the far side of that doorway or where your mates went or, on a bad day, which way is "front".
For fire and manoeuvre, imagine yourself in that V-shape patrolling across a field in the quiet bit in the middle of Saving Private Ryan when you hear the *snap*bang* of a bullet going past and a gunshot somewhere ahead. Everyone hits the dirt and tries to find a low spot into which to get, fast. Assuming everything goes amazingly well, which it does in training because "casualties don't" get any fitter, someone has to figure out where the enemy position is and tell the others, and then the ones with lousy arcs of fire stuffed full of their friends' bums have to get up and run forwards to positions from which they can shoot so that you can all give him a taste of the beach scene at the start of Saving Private Ryan so he'll keep his ugly head down for a while.
Having done that, you want to be somewhere other than the middle of this field, so four of you have the pleasure of lying in the crops, mud or whatever, shooting at the bunker, hut, trench or whatever in front of you while the other four get up and, one at a time, run past their mates' feet out to the side like a game of leap-frog. This puts four people in a ditch full of swamp, brambles, nettles and a dirty great rock that just belted you good and proper in the cheek as you dropped into the smelliest spot you possibly could, right next to it. Congratulations. That's going to swell up something awful for the photographs later. No, cam cream is not a topical analgesic or disinfectant.
Further up the ditch, past that bloody (literally, now) hawthorn tree someone very considerately left in your way, is a good spot for two people to stop and join in the general plinking of the enemy position. The other two get to move up and deliver a special little present in a little green can. Of course, that means going the next 100m up this ditch, then one going forwards alone to put said present in through the door. Once it opens itself you can all take it in turns to follow that route, shooting whatever's on the floor just to make sure, and take up new positions on the ground behind it.
All good ... and then it turns out he had backup, and this time you've got no happy ditch to follow so you're doing it the bouncy way. From left to right you're numbered one through eight. You divide into odd numbers and even numbers or one through four and five through eight or however you feel like dividing, and half of you shoot while the other half run forwards a bit and hit the dirt. Then it's their turn to make some noise while the first half get up, run forwards to slightly further forwards than they got and dive into the gravel (ow my knees) to take their turn shooting while the other half make their hop forwards (hmm, interesting flavour, mud) and so on a few metres at a time because you don't want to be up there long enough to get shot, bouncing up every time your mates dive down (wow, direct hit on rabbit droppings!) until someone basically jumps on the bad guy's head and makes a hole in it or he decides that running away is a better idea than staying to fight. Hey, are anyone else's knees bleeding?
The whole time you're doing that, you've got to be moving quickly enough to get the job done before you run out of ready ammunition, you've got to reload when you empty a magazine, you've got to shut your ammo pouch after than reload and before getting up to run again and you've got to make sure you don't get all bunched up together because if you do you're shooting into your mates' ankles.
Doing it right requires temporary psychosis. If you're not making the Quake 1 Fiend and Vore look sluggish, you're not trying.
