There aren't many situations where two isn't better than one (just use your imagination). With hypertrophy training, the same is true... if you use the right approach.
Can't find a summer job and are ambitious enough to hit the gym twice a day? Then this article will show you a few ways to go about it. As a bonus, I'll toss in a sample program utilizing many of the methods discussed.
Let's get to it!
Rule #1: Train in the AM and PM
When working out twice daily, workouts should be separated by a minimum of six hours in order to get maximum benefit from each session.
In other words, don't perform your first workout at 2PM and try to hit your second at 4PM. It's better to train in the morning and then again in the afternoon or early evening.
Rule #2: Perform the more demanding workout at the time of day in which you feel the best
This is a very relative rule, but it's one you have to consider when hitting the gym twice in one day. It's relative in that some people "feel better" when working out in the afternoon and some "feel better" when training in the morning.
The demanding nature of a particular workout, rep range, etc. can be relative, too. One person may breeze through a 12x4 session and struggle with the metabolic demands of the 8-12 rep range. And once again, the complete opposite may also be true for another individual.
In short, choose the workout that you view as more demanding and perform it at the time of day in which you generally feel the best.
Rule #3: Utilize a split routine
Full body and upper/lower splits are great tools and have their place, but neither are ideal for a two-a-day program. The volume would be insane and your body would break down, so don't even try it, bub. (You've been warned!)
When going with twice daily workouts, it's better to use broader splits. I recommend pairing two muscle groups together as shown below:
Pair 1: Chest/Back
Pair 2: Hip-Dominant Legs/Shoulders
Pair 3: Arms
Pair 4: Quad-Dominant Legs/Calves
The above pairings follow one of two rules. The pairing is either a) a set of antagonistic upper body muscles, or b) a large muscle group paired with a smaller one.
Large muscle groups which will require big, demanding movements (i.e. the squat and deadlift for quad and hip-dominant leg work) are paired with smaller muscle groups that require smaller, less demanding movements.
Rule #4: Never train the same muscle group twice in one day with the same set/rep scheme
If training a muscle twice in one day, different skeletal muscle components need to be targeted via differing stimuli/rep ranges. Training arms with sets of 10 in the AM and then again in the PM isn't productive as it'll only interfere with recovery from the first session.
Four Approaches to Two-a-Day Training
Now that we've got the preliminaries out of the way, let's take a look at a few approaches to two-a-day training.
Approach #1: Mix It Up
Many training programs call for the use of differing rep ranges within the same training phase in order to hit a given muscle group with varying stimuli over the course of a week. Usually there's a "heavy" day which calls for a lot of sets with only a few reps per set (i.e. 12x4), and then a "lighter" day in which less sets are performed, but the number of reps per set is increased (i.e. 5x12).
Well, a great way to approach two-a-day training is to mimic this heavy/light protocol, but within the same day as opposed to the same week. For example, using the "Mix It Up" approach, your AM session could be your heavy workout and then your PM session your light workout.
Here's how I'd set it up over the course of a week:
Monday AM: Chest/Back (12x4)
Monday PM: Chest/Back (4x12)
Tuesday AM: Hip-Dominant Legs/Shoulders (12x4)
Tuesday PM: Hip-Dominant Legs/Shoulders (4x12)
Thursday AM: Arms (12x4)
Thursday PM: Arms (4x12)
Friday AM: Quad-Dominant Legs/Calves (12x4)
Friday PM: Quad-Dominant Legs/Calves (4x12)
Again, keep rule number two in mind when selecting which rep range to use during in the AM and PM sessions. If you'd rather train heavy in the PM, go for it.
Also, supersetting the last two sets of the 4x12 workouts with an isolation movement is a good idea. For example, if performing bench presses, superset the last two sets with flyes. If performing shoulder military presses, superset the last two sets with lateral raises.
Because this approach is very demanding, I wouldn't use it for more than two weeks at a time.
Approach #2: Pump up the Volume
Another approach to two-a-day training is to pump up the weekly volume by training different muscle groups in the AM and PM. For example, if you typically train in the fashion below, you'd be able to blow through your normal weekly volume in only two days by training twice daily.
I'd recommend the following for a two-a-day program based on the "Pump up the Volume" approach:
Day 1 AM: Chest/Back
Day 1 PM: Hams/Shoulders
Day 2 AM: Arms
Day 2 PM: Quad-Dominant Legs/Calves
Day 3: OFF
And then the sequence would be repeated, taking a day off every third day.
Once again, because of the high volume, I wouldn't use this approach for more than two weeks at a time.
Approach #3: Quality Over Quantity
With the "Quality Over Quantity" approach, workload per session is cut in half by only training one muscle group per workout. This is a great approach to keep the CNS fresh, promote better workouts, and increase nutrient partitioning to each individual muscle. Here's how I'd set it up:
Day 1 AM: Chest
Day 1 PM: Back
Day 2 AM: Hams
Day 2 PM: Shoulders
Day 3 AM: Biceps
Day 3 PM: Triceps
Day 4 AM: Quad-Dominant Legs
Day 4 PM: Calves
Day 5: OFF
Then the sequence would be repeated, taking a day off every fifth day. If I were able to hit the gym twice a day on a regular basis, the majority of my training would be set up like this. Nothing leaves you feeling better than a 20-minute workout.
Approach #4: Specialization
With this approach, two-a-days are only used to target one or two lagging body parts that you'd like to bring up to par. A two-a-day specialization routine for arms could be set up like this:
Thursday AM: Arms (12x4)
Thursday PM: Arms (4x12)
Friday: Quad-Dominant Legs/Calves
The Double Trouble Hypertrophy Program
If you're able to train twice daily on a regular basis, the below is an awesome 12-week training block that's sure to yield spectacular hypertrophy and strength gains.
Week 1-2: Mix It Up approach, as outlined
Week 3: Deload. Low volume, 3x10
Week 4-5: Pump up the Volume approach. Heavy/average volume, 6x4
Week 6-7: Quality Over Quantity approach. Light/high volume, 8x10
Week 8-9: Quality Over Quantity. Light/low volume, 4x10
Week 10-11: Mix it Up
Week 12: Deload. Low volume, 3x10
The first two weeks follow the "Mix It Up" protocol outlined above. Week three is a transition/deloading week in which less than normal volume is performed (train each muscle group once a week with 3 sets of 10; there are no double sessions during this week).
Weeks four and five adhere to the "Pump up the Volume" approach utilizing a "heavy" set/rep scheme with average volume (6x4 is the scheme of choice here). Weeks six and seven switch over to the "Quality Over Quantity" approach with a light set/rep scheme and high volume (8 sets of 10 are in order during these weeks).
The next two weeks continue with "Quality Over Quantity" but with a moderate volume set/rep scheme (4x10). Each workout during these two weeks will take less than 15 minutes to complete.
"Mix it Up" is repeated during weeks ten and eleven, and the training block is completed with another deloading/supercompensation week at 3 sets of 10 per muscle group.
Two-a-days are an effective way of getting fast results in a short amount of time. That said, additional stimulation in and of itself isn't what's going to get you there. There are plenty of ways to screw it up, belittle your efforts, and overtrain — success is dependant on the right approach. And with the info presented here, you now have a few approaches to choose from.
If you've got the time and ambition to give Double Trouble Hypertrophy a go (and get some good nutrition in you), I'm confident you'll see immense gains in size and strength over the course of the 12-week program. Try it!