BUT IT'S ALWAYS 100% PC, BRO!
Because your busy Friday schedule has caused you to skip leg day, you now have to wait till next Friday to (maybe) hit legs again. This means your legs went two weeks without a growth stimulus, and so you've probably actually atrophied a bit. When you think about the larger implications of this, you're only training legs about twice a month. It's hard to argue that you're maximizing your growth this way.
If you actually are being consistent and hitting every one of your workouts, chances are that you're making some pretty good progress. This definitely isn't a bad way of training, and you can get very far training this way. Most professional bodybuilders (but not all) train each body part once per week. Yet these are guys moving 500 pound bench presses and 600 pound squats for reps, which causes massive trauma to their massive muscles. Can you do that? If not, you probably don't need an entire week to recover from your workout.
When was the last time that a workout actually made you sore for an entire week? Of course that probably happened to you a lot when you first started lifting, and even happens now occasionally when you do an absurd volume workout. But you're probably not training pants-shitting insanely week in and week out. Even if you are, you could probably benefit from a greater training frequency for each body part. This can be a great way to break through a stall in progress.
I first got the inspiration to write about this after listening to this (excellent) podcast that featured Dr. Mike Israetel:
http://openskyfitness.com/podcast/mike-israetel-proper-weight-lifting-techniques-ep-80/
Dr. Israetel brought up the point that most guys can really handle more frequent training than they think they can. For example, he recommends training chest 2-3 times per week (and even up to 4 times per week for small body parts like biceps), and that it doesn't need to get its own day. He also brings up the point that the seven-day week wasn't created muscle recovery periods in mind. People mostly choose to use once weekly splits because they're easy to organize, and that's fine. But there are plenty of training split methodologies that are just as easy to organize, but are also more effective. I'll discuss this more in a bit.
Some would argue that the 1X/week per body part split is superior because you can get in more total sets per body part in each workout. This is flawed thinking.
Training a body part more frequently can cause better muscle gains, even if you're using the same total weekly volume. Brad Schoenfield did a study on the matter, comparing your traditional bro-split with full-body workouts where each part was worked 3 times per week.
http://www.lookgreatnaked.com/blog/bro-split-versus-total-body-training-which-builds-more-muscle/
What this means is that doing 3 sets of 10 on the bench press with 200 pounds 3 times a week is better for muscle gain than doing 9 sets of 10 once per week. The difference wasn't huge between the two groups, but it was significant enough to report.
Most guys won't do 9 sets of 10 on bench press, but will introduce variation by doing 3 sets on flat bench, then 3 on incline and 3 on decline, or permutation of that. That's not bad, but if you split those 3 lifts up throughout the week on separate days you'd be able to either use more weight or get more total reps since you'll have more time for local chest recovery between each exercise (2-3 days rather than 5 minutes). Most of the time, 2-3 days is enough to recover from 3 sets of a chest press.
However, sometimes it won't be, and this is where you can manipulate the routine to include emphasis days and lighter days for certain body parts. This is something Dr. Israetel mentioned in the podcast as well. For example, say you're on an upper/lower split. You bench pressed and incline pressed on Monday and really annihilated your chest. Thursday has come around and it's time for your next upper body workout. You know you should be hitting chest for the second time of the week, but your chest is still sore as shit.
You have two main options here:
1. Pick a movement, either the same movement from Monday or a different one, to directly hit chest. Do this movement, and only this movement, as your chest workout. Do a light, moderate-volume workout to flush metabolites into your chest and get a nice pump. This will feel good and probably actually help your recovery more than if you simply didn't work chest at all.
2. Pick a movement that indirectly or less directly hits the chest. For example, close-grip bench presses will emphasize the triceps but will still hit the chest without stressing it too much.
Another thing you'll want to do if you're including multiple body parts in one workout is sometimes switch up the order of the body parts. For example, if you do a chest/shoulders/triceps workout in that order every time and you have small/weak triceps, you're doing yourself a disservice. Hitting movements that emphasize the triceps early in the workout will allow you to handle more weight and give you more growth where you're in need of it. If you save triceps for the end of every workout, that may be part of the reason they're weak in the first place.
Now let's talk about setting up a split.
If truly maximizing muscle gains is your priority, it's best be lifting more than 3 times per week, and using some form of a split. Devoting 4-6 hours a week to the gym isn't unreasonable for something that you're prioritizing.
Organizing these workouts is actually easier to do around a busy schedule than the once per week splits because if you miss a workout, you can simply pick up where you left off for your next workout and not have missed an entire week of training for a body part. Don't feel like you have to operate in a 7-day rotation. If you're like me and have a schedule (like for school) that allows you to only work out on certain days, this type of split is great. I usually pick 5 or so days of a week and go through a rotation, always working out on the same days but not necessarily doing the same workouts on each day week-to-week.
Two-way splits: Alternate between the two days for 4-6 total days per week
Option 1:
Day 1: Chest/Shoulders/Arms
Day 2: Legs/Back
I've used this many times and like it a lot.
Option 2:
Day 1: Upper body
Day 2: Lower body
Again, something I've used a lot to good results.
Option 3:
Day 1: Torso (chest, shoulders, back)
Day 2: Limbs (legs, arms)
This is Dorian Yates's intermediate workout.
Option 4:
Day 1: Chest/Shoulders/Triceps/Back (2 movements for back)
Day 2: Biceps, forearms, Calves, Hamstrings, Quads
This is the standard DogCrapp split.
If you did 5X/week here, you'd be hitting your Day 1 three times in the first week and Day 2 twice that week. The next week, you'd hit Day 1 twice and Day 2 three times. It all balances out nicely.
Three-way splits: Do each workout twice per week for 6 days total per week
Option 1:
Day 1: Push (Chest/shoulders/triceps)
Day 2: Pull (Back/biceps/forearms)
Day 3: Legs (Quads/hams/calves)
Always solid.
Option 2:
Day 1: Chest/back
Day 2: Shoulders/arms
Day 3: Legs
The classic Arnold split.
Full-body splits
Hit a pressing movement, a squat or deadlift variation, an upper body pulling movement (chins or rows), and a couple of small accessory movements in every workout. Do 3-6 days per week.
Increasing frequency for small body parts
Smaller body parts can withstand more frequent training, even around 4 times per week. A lot of golden-era bodybuilders trained abs every day. This can be done with any of these splits.
Let's use someone who desperately wants to improve their biceps as an example. We'll make a 5-way split. This is a bit more complicated than the other versions but still very manageable.
Day 1: Quads, chest, triceps, biceps
Day 2: Back, hamstrings, biceps
Day 4: Biceps, triceps, forearms
Day 4: Quads, hamstrings, calves
Day 5: Chest, back, biceps, calves
As you see, there are endless ways you can set up a split. Don't get caught up in the idea of only training each body part once per week. If you do, you're short-changing yourself a great deal of potential muscle gain.
