Bro Split Routines: How Often Should You Work Out to Build Muscle?

How often should you work out if you want to build muscle? Are bro split routines, where you hit each muscle group just once a week, the way to go? Or will you see better results working each muscle 2-3 times a week?

Let’s find out…

What is a Bro Split?

The term “bro split” typically refers to a training program that involves hitting each muscle group directly once a week.

Although you might train between 4 and 6 times a week, each workout focuses on just one or two muscle groups. As a result, the number of sets you do for each muscle group in any given workout is relatively high.

With a full-body workout, for example, you might do 3-5 sets for each muscle in a single workout. But with a bro split, you’ll be doing a lot more volume to compensate for the fact each muscle is being trained less often.

Sample Bro Split Routine

While there are plenty of different ways to set up a bro split routine, here’s one example of how it might look:

• Monday: Chest/Back
• Tuesday: Legs
• Wednesday: Shoulders/Traps
• Thursday: Off
• Friday: Biceps/Triceps/Abs
• Saturday: Off
• Sunday: Off

One of the defining characteristics of a bro split is that each muscle is trained once a week. However, while each muscle group is trained directly once a week, some muscles can, depending on how your routine is structured, end up being trained twice a week. 

When you train your chest and back, for example, the biceps, triceps and deltoids are going to be involved to some degree. Rows and pulldowns work the rear deltoids and biceps as well as the back. Any sort of pressing movement, be it the bench press or seated dumbbell press, will also hit the triceps and shoulders.

In other words, if you’re working your shoulders and arms on different days to your chest and back, the deltoids, biceps and triceps will end up trained twice a week, rather than just once.

Bodybuilders and Bro Split Routines

What prompted me to write this was an email that arrived at Muscle Evo HQ this morning. Here’s what it said:

“You’ve explained on your website that training a muscle more than once a week is more optimal for growth and this explains the popularity of full body workouts and upper/lower splits.

“What then confuses me is why are most bodybuilders, whose aim is to be as muscular as possible, training a muscle once a week? Wouldn’t they naturally incline towards a more result producing routine to boost their results?”

It’s a good question.

After all, bodybuilders are some of the most muscular people on the planet.

While there’s no universal training template followed by all bodybuilders all of the time, most of their training programs do have a few things in common.

And following a bro split, where they train each muscle group once a week certainly appears to be one of those things.

One study I looked at, published in the Journal of Strength and Conditioning Research, surveyed a group of 127 competitive bodybuilders [1].

It shows that 7 out of 10 trained each muscle group once a week. The rest did it twice a week.

So why are most of these guys (whose main aim is to be as muscular as possible) following a bro split routine, where they hit each muscle group once a week, and I’m telling you to do it more often?

What’s going on?

Bro Split Routines, Drugs and Muscle Growth

First off, we have the drug factor to consider.

In the survey I just mentioned, almost 8 out of 10 of the respondents who competed in amateur bodybuilding reported using anabolic steroids.

And they were just the ones who admitted it.

If I was on the sauce, and knew that getting caught would land me in trouble, I certainly wouldn’t be telling anyone about it in an online survey.

Anabolic steroids can make a big difference to your results, giving you a skewed picture of the effectiveness of a particular style of training.

If you look at the way bodybuilders trained before drug use was widespread, hitting a muscle group more frequently was a lot more popular than it is now.

Even back in the day when Arnold was winning Mr. Olympia contests (when drug use was par for the course) most top bodybuilders were still training a body part more often than once a week.

There’s also the “that’s how it’s always been done and it seems to work just fine” line of thinking.

Some guys will always do what they’ve always done, or at least what is commonly accepted practice in bodybuilding circles.

Nothing to say they wouldn’t get better results with more frequent training.

Genetics and Muscle Growth

Next up is genetics, which have a huge impact on your ability to add muscle.

In one trial, researchers looked at the results of men who built the most muscle (high responders) and those who built the least muscle (low responders) after a 12-week training program [3].

To their surprise, they found roughly four times greater gains in the high versus the low responders.

In other words, let’s say that two guys start out lifting weights. Both follow the same training program and eat the same diet for three months. The high responder gains eight pounds of muscle. The low responder, on the other hand, gains just two pounds.

If someone has great “muscle building” genetics, they can often get away with training (and nutrition) methods that are less than optimal.

Even if the low responder were to follow the greatest training and diet program ever devised in all of human history, the high responder may still end up building muscle more quickly.

Since there are so many factors that affect how muscular someone is, you shouldn’t automatically try to copy what a particular group of people are doing simply because of the condition they’re in.

How Many Times a Week Should Each Muscle Be Trained?

Although hitting a muscle group just once a week is less popular than it used to be, research shows that it’s still an effective way to build muscle.

A good example comes from a study published in the Journal of Strength and Conditioning Research, where scientists put two groups of trained men through an eight-week training program [4].

Both groups did the same exercises, in the same order, for the same number of sets. The only difference was in how often each muscle group was trained.

• Group one hit each muscle group once every seven days, squeezing all their training for the week into just two workouts.
• Group two spread their training volume across four rather than two workouts, hitting each muscle group twice a week rather than once.

Here’s what the training program in the once-a-week group looked like:

Monday

• Bench Press 8 sets x 8-12 reps
• Dumbbell Flyes 8 sets x 8-12 reps
• Triceps Pressdown 8 sets x 8-12 reps
• Squats 8 sets x 8-12 reps
• Leg Extension 8 sets x 8-12 reps

Thursday

• Lat Pulldown 8 sets x 8-12 reps
• Straight Arm Pulldown 8 sets x 8-12 reps
• Biceps Curl 8 sets x 8-12 reps
• Seated Leg Curl 16 sets x 8-12 reps

The twice-a-week group did the same number of sets for each muscle group, but spread them across four rather than two workouts.

Monday

• Bench Press 4 sets x 8-12 reps
• Dumbbell Flyes 4 sets x 8-12 reps
• Triceps Pressdown 4 sets x 8-12 reps
• Squats 4 sets x 8-12 reps
• Leg Extension 4 sets x 8-12 reps

Tuesday

• Lat Pulldown 4 sets x 8-12 reps
• Straight Arm Pulldown 4 sets x 8-12 reps
• Biceps Curl 4 sets x 8-12 reps
• Seated Leg Curl 8 sets x 8-12 reps

Thursday

• Bench Press 4 sets x 8-12 reps
• Dumbbell Flyes 4 sets x 8-12 reps
• Triceps Pressdown 4 sets x 8-12 reps
• Squats 4 sets x 8-12 reps
• Leg Extension 4 sets x 8-12 reps

Friday

• Lat Pulldown 4 sets x 8-12 reps
• Straight Arm Pulldown 4 sets x 8-12 reps
• Biceps Curl 4 sets x 8-12 reps
• Seated Leg Curl 8 sets x 8-12 reps

So, which group gained the most muscle?

Ultrasound scans of the biceps, triceps and quadriceps show no significant difference in results between the two groups. Whether a muscle was trained once or twice a week, the amount of muscle growth was very similar.

You can see the full set of results below:

Triceps
Group One + 5.5 %
Group Two + 5.7 %

Biceps
Group One + 6.1 %
Group Two + 5.7 %

Vastus Lateralis (quadriceps)
Group One + 9.2 %
Group Two + 9.6 %

Rectus Femoris (quadriceps)
Group One + 9.2 %
Group Two + 10.9 %

When the researchers calculated volume load (sets x reps x weight), the group hitting each muscle group twice a week ended up doing the most work, which is exactly what you’d expect to happen. 

Over a longer period of time, the increase in volume load with the higher training frequency may well lead to faster gains in size.

To quote the researchers directly:

It is plausible to hypothesize that this greater [volume load] achieved through high frequency protocol if executed for a longer time frame (more than 8 weeks) may possibly culminate in a significantly greater increase in strength and hypertrophy compared with a single-session per muscle group.”

Bro Split vs Full Body Workout

In a similar study, a team of US researchers compared a full-body workout with a split routine [5].

A group of 19 men, with an average 4.5 years of training behind them, took part in the trial.

Subjects in the split routine group trained chest and back on Monday, legs on Wednesday, and shoulders and arms on Friday. The full-body group trained their whole body in each workout, using the same exercises as the split routine group.

Both groups trained three times a week for eight weeks. All sets were taken to concentric muscular failure, with 90 seconds of rest between sets.

Here’s what the training programs looked like in both groups:

Split Routine

• Monday: Chest/Back
• Tuesday: Off
• Wednesday: Legs
• Thursday: Off
• Friday: Shoulders/Arms
• Saturday: Off
• Sunday: Off

Chest/Back

• Bench press 3 sets x 8-12 reps
• Incline press 3 sets x 8-12 reps
• Hammer chest press 3 sets x 8-12 reps
• Lat pulldown (wide grip) 3 sets x 8-12 reps
• Lat pulldown (close grip) 3 sets x 8-12 reps
• Seated row 3 sets x 8-12 reps

Legs

• Squat 3 sets x 8-12 reps
• Leg press 3 sets x 8-12 reps
• Leg extension 3 sets x 8-12 reps
• Stiff-leg deadlift 3 sets x 8-12 reps
• Hamstrings curl 3 sets x 8-12 reps
• Good morning 3 sets x 8-12 reps

Shoulders/Arms

• Shoulder press 2 sets x 8-12 reps
• Hammer shoulder press 2 sets x 8-12 reps
• Upright row 2 sets x 8-12 reps
• Hammer curl 2 sets x 8-12 reps
• Barbell curl 2 sets x 8-12 reps
• Preacher curl 2 sets x 8-12 reps
• Cable pushdown 2 sets x 8-12 reps
• Skull crusher 2 sets x 8-12 reps
• Dumbbell overhead extension 2 sets x 8-12 reps

Full-Body Workout

• Monday: Full Body Workout 1
• Tuesday: Off
• Wednesday: Full Body Workout 2
• Thursday: Off
• Friday: Full Body Workout 3
• Saturday: Off
• Sunday: Off

Full Body Workout 1

• Squat 3 sets x 8-12 reps
• Stiff-leg deadlift 3 sets x 8-12 reps
• Bench press 3 sets x 8-12 reps
• Lat pulldown (wide grip) 3 sets x 8-12 reps
• Shoulder press 3 sets x 8-12 reps
• Hammer curl 3 sets x 8-12 reps
• Cable pushdown 2 sets x 8-12 reps

Full Body Workout 2

• Leg press 3 sets x 8-12 reps
• Hamstrings curl 3 sets x 8-12 reps
• Incline press 3 sets x 8-12 reps
• Lat pulldown (close grip) 3 sets x 8-12 reps
• Hammer shoulder press 2 sets x 8-12 reps
• Barbell curl 2 sets x 8-12 reps
• Skull crusher 2 sets x 8-12 reps

Full Body Workout 3

• Leg extension 3 sets x 8-12 reps
• Good morning 3 sets x 8-12 reps
• Hammer chest press 3 sets x 8-12 reps
• Seated row 3 sets x 8-12 reps
• Upright row 2 sets x 8-12 reps
• Preacher curl 2 sets x 8-12 reps
• Dumbbell overhead extension 2 sets x 8-12 reps

Ultrasound imaging was used to track changes in muscle size in the biceps, triceps, and vastus lateralis (quadriceps), while maximal strength was measured in the bench press and squat.

So, what happened? What did the results show?

With the exception of the increase in biceps thickness, none of the differences between the groups were statistically different.

But the researchers did find that the effect size (which refers to the size of the difference between groups) “markedly favored” the higher frequency protocol.

In other words, there was a clear trend towards faster gains in the group hitting each muscle group three times a week.

The differences between the groups weren’t dramatic – a millimeter or two here and there. But this study lasted just eight weeks. Over months and years, those small differences can add up.

You can see the full set of results below.

Biceps
Full Body + 3.2 mm (6.5%)
Split Routine + 2.1 mm (4.4%)

Triceps
Full Body + 3.6 mm (8%)
Split Routine + 2.3 mm (5%)

Vastus lateralis
Full Body + 3.6 mm (6.7%)
Split Routine + 1.2 mm (2.1%)

Bench press
Full Body + 10.2 kg (10.6%)
Split Routine + 6.3 kg (6.8%)

Squat
Full Body + 13.8 kg (11.3%)
Split Routine + 12.1 kg (10.6%)

NOTE: Because the biceps and triceps are involved when you train your chest and back, the results for the biceps and triceps represent more of a comparison between two and three weekly training sessions. For vastus lateralis (one of the quadriceps), it was three versus once a week.

On the whole, it was the full-body group that made the fastest gains. However, it’s not like the split routine group made no gains at all. They just didn’t build muscle at the same speed as the full-body group.

There’s also the “novelty factor” to consider. Most of the subjects (16 out of 19) taking part in the study were already using a split routine.

It’s possible that the full-body group benefited from the unaccustomed stimulus of working each muscle group more often than once a week.

If you repeated the study, but this time using a group of people who were accustomed to performing full-body workouts, the results may have been very different.

Scientists from Brazil have also compared a full-body workout with a split routine [6]. But this time, rather than hitting each muscle group three times a week, the full-body group trained on consecutive days, Monday through Friday.

Subjects who trained a muscle once a week did two exercises in each workout, performing between 5 and 10 sets per exercise. Participants in the full-body workout group did a total of 11 exercises, and 1-2 sets per exercise.

Both groups ended up doing the same number of sets for each muscle group, but it was spread out differently across the week.

What happened? Who gained the most muscle?

After eight weeks of training, there were no statistically significant differences in terms of strength or size gains between the two groups. A training frequency of five times per week delivered similar gains to a training frequency of once a week.

However, while there were no statistically significant differences between the two groups, the full-body workout group did register a slightly greater increase in lean body mass (a reasonable proxy for muscle mass) compared to the once-a-week group.

In summary, bro splits can certainly work in the sense that they make your muscles grow. However, most research shows that training a muscle group once a week is no better than training it 2 or 3 times over the same period. 

While the difference between the two approaches are often relatively small, it’s the more frequent training programs that lead to more muscle being gained.

Bro Split vs PPL

How does the bro split compare with a push/pull/legs routine?

With a push/pull/legs routine, you do three different workouts: a push workout, a pull workout and a legs workout.

In the push workout, you train your chest, shoulders and triceps. The pull workout is dedicated to back and biceps. On legs day, you train the quadriceps, glutes, hamstrings and calves.

Depending how often you train, a PPL routine and a bro split have a lot in common. In fact, a 3-day PPL routine is a type of bro split, in the sense that each muscle group is trained just once a week.

Here’s what the 3-day version of the push/pull/legs split looks like:

• Monday: Chest, Shoulders, Triceps (Push)
• Tuesday: Off
• Wednesday: Back, Biceps (Pull)
• Thursday: Off
• Friday: Quads, Hamstrings, Calves (Legs)
• Saturday: Off
• Sunday: Off

If you do want to use a PPL routine, I think they’re better suited to a training frequency of 5-6 days a week, rather than 3 or 4. 

This way, you get some of the benefits of a bro split, in the sense that the number of sets you do for each muscle group in a single workout is relatively high. But each muscle group is trained more often than once a week, creating a much more favorable environment for growth.

Do Bro Splits Work?

All things considered, I’d still recommend hitting each muscle group more often than once a week.

But that doesn’t mean you won’t see results with just one weekly training session per muscle group. It’s not like leaving seven days between each body part produces zero gains. You can build muscle with any type of weight training program, a bro split included.

However, if you want to maximize your rate of growth, I think you’re better off training each muscle group at least twice every seven days.

Why does hitting a muscle group twice a week work better than training it once a week?

One of the key driving forces behind muscle growth is muscle protein synthesis, which refers to the creation of new muscle protein. And it’s the gradual accumulation of this new muscle protein that makes your muscles bigger [7].

After you train, protein synthesis goes up. But it’s back to normal a couple of days later [8]. And creating more muscle damage doesn’t appear to make the rise in protein synthesis last any longer [9]. Put differently, there’s an upper limit on the amount of stimulation your muscles can respond to in any given workout.

In other words, when you follow a bro split and train a muscle once a week, it might spend a few days “growing” after the workout. But leaving seven days before you train that muscle again means missing out on several additional opportunities to stimulate growth.

The Law of Individual Differences

Working a muscle group 2-3 times per week may, on average, produce a faster rate of growth than training it once a week.

However, no two people respond to the same training program in exactly the same way, and we can’t exclude the possibility that there may be a set of people who thrive on bro split routines that involve training less frequently.

We know, for example, that people with a specific variant of the ACE gene gain just as much strength with single versus multiple-set training programs, while people with another variant make faster progress with multiple sets [10].

The same may hold true for training frequency. Some people may make equal or faster progress working a muscle group once a week compared to twice or three times a week.

In one study, roughly 3 out of 10 subjects showed greater gains in muscle mass when they trained a muscle five times per week [11]. Another 4 out of 10 saw faster results when they trained that same muscle 2-3 times each week. The others made similar progress irrespective of how often they trained.

Even after training volume was taken into account, some folks gained muscle faster on the higher training frequency [12].

I will always recommend an approach to training and diet that I think will work for most people, most of the time.

But “most people, most of the time” doesn’t mean all people, all of the time, and there will always be exceptions and outliers.

There is no universally correct training frequency that works equally well for everyone, nor are there rigid guidelines that determine exactly what your training routine should look like.

All of which means you’ll need to be willing to experiment. By that, I mean testing out different training frequencies with the aim of finding the one that works best for you.

The Bro Split: What’s Right and What’s Wrong?

There are many different ways to set up a training program. Each comes with its own benefits and drawbacks. Here are some of the pros and cons of the bro split:

The Bro Split: Pros

Many people like the idea of dedicating an entire workout to just one or two muscle groups, mainly because it means walking out of the gym with those muscles feeling pumped up and ready to explode. Getting a pump is no guarantee that muscle is going to be gained any faster, but it still feels good.

For some, a bro split is simply a more enjoyable way to train. They thrive on the variety of training different muscles, and doing different exercises, from one day to the next.

Adding a large amount of muscle mass to your frame muscle requires sustained and consistent effort over a number of years. And a big part of staying consistent is actually wanting to go to the gym. 

If following a bro split makes it far more likely that you’ll do the work necessary to make your muscles grow, that’s a major benefit. A training program that’s optimal for muscle growth isn’t optimal if you don’t do it.

Dividing your training across 4-6 days, rather than 2-3, can mean shorter workouts, which are often easier to fit into your day, particularly if you have a home gym set up in your garage, basement or spare room.

If you prefer shorter, more frequent training sessions, and you can make it to the gym on a regular basis 4-6 days a week, the bro split can work well.

The Bro Split: Cons

From a muscle-building point of view, most research shows no benefit to training a muscle less often than twice a week. Chances are the gains will come more slowly compared to more frequent training.

While lifting weights 4, 5 or 6 days a week is going to be a benefit for some, not everyone is willing or able to train that often. If you’re only able to make it to the gym two or three times a week, for example, you’ll be better off with a full-body workout, or an upper/lower/full body hybrid.

A bro split isn’t ideal if your main goal is to increase maximal strength in a compound lift like the squat, bench press or deadlift. In this case, you’re better off with a training program that allows for more frequent practice of whatever lift it is you’re trying to improve.

If you’re someone who needs a relatively high volume of training to make your muscles grow, trying to cram all those sets into a single workout is counterproductive, for a couple of important reasons.

Let’s say, for example, that you decide to hit each of your major muscle groups with a total of 16 sets per week.

Do all those sets in a single training session, and your performance is going to suffer. As fatigue accumulates, some of the sets that come later in a workout won’t involve as many stimulating reps. Over time, this is likely to mean that muscle ends up being built more slowly. 

What’s more, there’s only so much stimulation your muscles can respond to in any given workout. While six sets per muscle group may work better than three sets, it doesn’t necessarily follow that 12 sets will outperform six by the same margin.

Beyond a certain point, you end up creating large amounts of fatigue and damage (all of which takes time to recover from) without stimulating additional gains. 

More frequent workouts allow you to provide just the right amount of stimulation required for growth, but not so much that it interferes with your ability to recover for the next workout.

Rather than doing 16 sets per muscle group in a single workout, then waiting a week to do the same thing again, you’re better off splitting that workout in two. That is, you’d do 8 sets in the first workout, then do the same thing again a few days later. 

This gives you two opportunities to stimulate growth over the course of a week, rather than just one.

Final Thoughts

If you want to gain as much muscle as you can as quickly as possible, a bro split is not ideal. You’ll be better off with an upper/lower or a push/pull split, where each muscle group is trained directly twice a week, rather than once. 

Assuming you’re doing all the right things in terms of diet and recovery, and your workout volume isn’t excessive, your muscles don’t need a full seven days of rest before they’re ready for action again.

While the extra rest certainly won’t cause muscle to be lost, the gains won’t come as quickly as they otherwise might have done.

However, while you’re unlikely to build muscle as quickly as you would have done on a higher frequency routine, impressive gains can still be made.

If you’re seeing results training a muscle once a week, then stick with it. I’ve known plenty of people build muscle with that type of approach.