This is actually for a paper for school but I was wondering what type of workout routines professional bodybuilders/fitness models use?
Do people use routines that are commonly recommended like phul/phat/gcdlz for years all the way until they look like this? https://i.stack.imgur.com/8prB7.jpg
Or what do they use to actually get to that point? (aside from probably a fair amount of substances) Thanks!
TL;DR: Exactly how they train is personalized, but they do a lot of it; also, diet is just as important as the training.
Competitive bodybuilders (the Mr. Olympia kind) tend to use some variation of the "bro split" where you train one or two muscle groups per day, 4-6 days a week, so that you hit all muscle groups every week (and equally important, they get 1-3 rest days per week, because muscles are built during recovery).
Their exact workouts will be adapted over time depending on a lot of things, including injuries, visual asymmetries, weak points, current trends, how their substances affect them, if they are on a diet or a calorie surplus, etc. (This is also the reason why you generally shouldn't take a famous bodybuilder's current training program, use it for yourself, and expect to look like them - that program is designed not for you to get where they are, but for them to get from where they are to where they want to be. Also, they probably do a lot more PEDs than you do.) T-Nation has an article on how to make a bodybuilding program which might be helpful to understand how these folks work out.
However, to look like the guy in the photo, you should be more concerned with your diet than with your exercise (or which substances to use). He's certainly well-trained and good-looking, but not particularly massive - except his abs. Visible abs like that are more reliant on having a low body fat percentage (and likely, good genes) rather than exercising for muscle mass. ("Abs are built in the kitchen", which has been discussed before on this site.)
The guy's name, by the way, is Matthew Terry unless my google-fu fails me, and according to a tabloid "his ripped physique is down to a combination of daily gym sessions and clean eating", and "to maintain his washboard stomach he likes to hold the plank position". That's not much detail (although there may be more in the linked video interview), but clean eating and a good amount of workout with extra focus on the parts you're most concerned with sounds familiar from when we looked at how bodybuilders train.
There's also an interview on Men's Health which gives more detail:
MH: What is your regular exercise regimen and what areas do you primarily focus on?
MT: I generally try to work out four to five days a week, along with any
other small workouts that I do at home during my spare time. Some days I do a full body workout at the gym and other days target specific muscles. I like to focus the most on my core. I try to incorporate it into my workouts every time I exercise.
MH: What did you do to get in shape specifically for the campaign?
MT: For the campaign, I really focused on my diet and exercising. I pushed myself harder than I normally would and I switched my workouts to consistent circuit training and isometric training, but still did full body and targeted muscle workouts.