Surely they must be doing something right then? I keep hearing internet people criticize the "bro splits" (programs where you train each muscle group on its own dedicated day of the week), but in my gym, they're by far the most common routine, and everyone on them seems happy and confident with the body they have.

I would say that in my gym, there's generally 4 types of people:

  1. Women, who generally rotate between the treadmills, the leg-exercises like squats and DL, and the ab-station.
  2. BIG and STRONG men, who do upper/lower or full-body routines with barbell compound workouts (squat, DL, bench, press, row).
  3. Skinny men, who do a bit of everything, probably just trying to get their feet wet.
  4. The muscular and LEAN built "cool guys of the gym" who spend all their time near the dumbbells (especially on arms day, goTTa gEt tHeM gUnS), doing all sorts of isolation workouts on a bro split routine.

So clearly, compound movements seem better suited for guys that want to get BIG and STRONG (read: fat and huge), whereas bro-splits genuinely do work for guys that just want to get a decent muscular build but remain lean and athletic.

So why do they get so much criticism?

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    Don't forget that you're dealing with human people who love to establish distinctions from one another as a source of validation. Most things subject to nerdy interest guide people to wanting to prove themselves as knowing the most or being the best; so assume that a lot of criticism will have some signaling of one's worth (by kicking somebody else down) in it. "Bigger is better" also seems pretty endemic in the "heavy lifter" community, so people with that goal may not just put enough value into another goal to objectively discuss it, even if their approach may actually be better.
    – millimoose
    Commented Aug 9, 2020 at 13:26
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    Skinny men, who do a bit of everything, probably just trying to get their feet wet. Or perhaps the smartest and healthiest people in the room. Curious that you dismiss this group so readily.
    – J...
    Commented Aug 10, 2020 at 17:08
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    I'm one of those skinny guys (runner/cyclist), but I understand that weight training is also key to optimal health. I do pullups, bench, dips, military press, bent rows, squats and deadlift regularly. I've had to adapt a bit with my gym being closed the last few months, but focus on compound lifts. When I started, I could barely do 2 pullups and 5 dips. Now I can strap on a 35 and crank out 3 sets of 10. I didn't get bigger and I don't want to, but I got leaner and much stronger. Don't underestimate the skinny guys! Compound lifts are the way to go.
    – DSway
    Commented Aug 11, 2020 at 2:55
  • @DSway How did you get your pullups up? Been trying and trying to get them up and continue to struggle with 5..... Commented Aug 11, 2020 at 13:11
  • @dc3rd, I did P90X and used Tony Horton's suggestion of using a chair to do 'assisted pullups'. I let me legs do just enough so that I could do a set of 7-10 reps. At the end of the 90 days, I could do 5 pullups. It took more than a year before I could do 10. Patience, persistence and consistency were key for me. But I'm a distance runner, so I don't give up easily. It helps that I'm light, so I don't have as much weight to pull up. Also, a strong core can help.
    – DSway
    Commented Aug 11, 2020 at 14:34

9 Answers 9


That's because your gym is a typical commercial gym where majority of people don't have any idea what they're doing and they're just going with the motions. Go to a gym that caters to strength athletes or bodybuilders and your experience will be extremely different.

Problems with bro splits:

  1. Not enough volume. You have to practice progressive overload to build muscle. You have to. There's no way around it. You have to lift more than you did previously. A bro split typically will only work any particular muscle group once, maybe twice a week. Any full-body routine, even beginner ones, will work every muscle group to some degree at least three times a week. A sufficiently advanced person may work every muscle group at least five times a week, while adding a small "bro-split" routine to fill out neglected areas. So while bro-splits will work at first, it'll be difficult to add volume when you're only working a body-part once, maybe twice a week.

  2. Neglected muscle groups. Most "bro-split" routines are trash. They focus on the glamour muscles, and as such don't build your entire body. Doing so will prevent you from advancing, thus prevent you from practicing progressive overload because other parts of you aren't keeping up.

  3. Wasted time and effort. Why do leg extensions, leg press, leg curls, calf raises, donkey kicks, and planks when a heavy squat will work all those for me? Even though squats neglect hamstrings more than quads, I could squat first then finish with leg curls and be out of the gym before the bro is even on his fourth workout. Or better yet, squat first and finish with Romanian Deadlifts so work my upper back a bit more while I'm at it.

Is it possible to get very muscular on a completely isolated "bro-split"? Of course. People do it all the time. The difference is it's usually very well planned out and executed very meticulously by people who know what they're doing.

So clearly, compound movements seem better suited for guys that want to get BIG and STRONG (read: fat and huge), whereas bro-splits genuinely do work for guys that just want to get a decent muscular build but remain lean and athletic.

People who are BIG and STRONG now had "decent muscular builds" before they became BIG and STRONG. They didn't wake up with that muscle. They built up to the decent muscular build people and surpassed them. Compound movements got them to those levels at a much faster rate than the bro-split guys.

Also, people who train for strength don't care much for the aesthetic so they eat to perform. If they kept calories in check and cut every once in a while, they'd be "yoked".

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    This answer has a lot of emotionally charged language, I'm not used to seeing that on SE. Commented Aug 9, 2020 at 22:42
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    @TankorSmash The original question was pretty emotionally charged (especially before the edits) so I responded in kind.
    – DeeV
    Commented Aug 10, 2020 at 0:08
  • 1
    I'm not seeing an edit history on either the question or your answer, though. Commented Aug 10, 2020 at 1:42
  • 1
    @user2357112supportsMonica Wait. Ignore that. I made edits to another question and thought it was this one. My mistake.
    – DeeV
    Commented Aug 10, 2020 at 12:17
  • 4
    @DeeV I don’t think that’s necessarily a good reason to respond in that manner.
    – Tim
    Commented Aug 10, 2020 at 18:16

Here is sort of an outsider perspective: as a climber, you have very specific training goals that are almost completely opposed to body-building for muscle mass. For a climber, weight efficiency is very important and you need two kind of strengths: the instantly available maximum power for a single move, and the continuously available power for moving in overhanging terrain. Also much of the short-time actuation is delivered through arms and fingers and the respective sinews and tendons are quite slower to change under training than muscles, so strength coming at the cost of weight, even if it is proportionate to weight, is detrimental to your health.

For the first kind of strength, the ratio of muscle fibres that can be activated is important, for the second, the continuous provision of resources to operating muscles through circulation and capillaries is important.

For neither, muscle mass is helpful: it's more a matter of the constitution of the muscles. What muscle mass provides is local storage of nutrients for more than a moment but still quite limited amounts of time, like when doing a weightlifting contest.

So climbers tend to do things for training muscle utilisation at 5 reps or less, and power endurance at 20 reps or more, and avoid the muscle-mass building in-between like the plague, assuming that you are not just idling but working close to capacity.

Building muscles, in contrast, relies on starving muscles regularly in a manner that can be fixed by local nutrient depots. Those kind of extraneous depot is something that a body will not keep around without need, particularly if other muscle groups are clamoring for them. You don't want your body to transfer its resources around on a weekly schedule, you want to keep stocking up.

Now of course it depends on your own personal goals where you want to go. If you take a look at "Conan the Barbarian" movies that were made near the time where the main actor was crowned "Mister Universe", you'll see that the kind of leg musculature makes for very awkward running scenes because there just isn't enough room for all those muscles to get around one another.

Also when you keep inflating muscles with isolated routines without allowing for "natural deflation" in between, the visual balance of your muscle groups is not determined by natural use cases (and thus idealised natural proportions) but by your training plan and design, and that can lead to outrightly bizarre results.

A "bro" routine is a bit more self-stabilising in its results when you don't actually have a sensible plan and/or a good control over its progress. So there is little wonder it gets the "works for me" tag for people who aren't actively competing athletes.


The critique of bodybuilder split routines is not that they don't work. They obviously work, so anyone who says they don't is either ignorant or speaking without thinking. It's that a bodybuilder routine may be sub-optimal for some goals. Usually the critique is that a powerlifting foundation is more effective to build whole-body mass. Personally I think that the distinctions are drawn too clearly, and we should all be open to a more "powerbuilding" hybrid approach when called for.

My most recent three or four gyms have not had a population distribution like yours. Crucially, you omit one category they each have had: a plentiful minority of lean, athletic men and women who use powerlifting and Oly lifting exercises and rep schemes to either look better at their current weight or to get bigger.

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    At the commercial gym I went to, I was the only guy who squatted and deadlifted as far as I could tell. And I'm tiny. The really big guys were all doing bro-splits. At the powerlifting gym, everyone was powerlifts from big guys to tiny guys to grandmas.
    – DKNguyen
    Commented Aug 10, 2020 at 2:11
  • He hasn't omitted that category. He is calling the lean, athletic men "skinny" in his post because he's clueless. Commented Aug 11, 2020 at 17:38

if you train for many years you will get muscular even with the most stupid training routine...

do you wanna get big and muscular in 8 years of training or only in 3?

make your choice.

there's many ways to reach a point, but there is always one road which is incredibly worse than others and one road which is the most time efficient.

also you are categorizing people you don't even know in your own gym and generalising them as being a worldwide thing. And someone like you who make such types of question has probably been to only one gym in their entire life and not for long.

  • 1
    The first sentence is very true. Commented Aug 9, 2020 at 6:03

There's a big reason why you can't just copy the routine of the biggest meathead at your local big box gym and call it a day:

Selection Bias.

Much like a diet, a better test of an exercise regimen is not whether or not one could achieve the desired outcome, but what percentage of people on the regimen achieve their desired outcome. Those guys you see doing bro splits and looking jacked are the gifted: the genetic lottery winners.

And just like by looking at lottery winners and neglecting the entire cohort of lottery ticket purchasers you can erroneously conclude that the lottery is a good investment, you can't just look at the teeny tiny sliver of people who tried a bro split and had success and think that it would work for you. Even in the handful of years I worked at the gym in college I watched a lot of people try bro splits and... not achieve their goals. They moved on to better programs or just quit showing up. You're only seeing the handful of survivors.

And even if you are amongst the blessed, as other answers have said there are more optimal ways to get there.


By "Bro Splits", it seems that you are referring to a split routine wherein a different muscle group is targeted each day with machines or dumbbells, completely avoiding any compound lifts.

Do Bro Splits work? Well, that depends on what you mean by "work", which of course depends on your goals. If your goal is to get sweaty and burn a few calories each day in the gym while avoiding boredom, then Bro Splits definitely work. If your goal is to put on a little bit of muscle mass over the course of months of training, Bro Splits might work (depending on the details of the training schedule). If your goal is to gain some hypertrophy in specific muscle groups strictly for aesthetics and not for useful strength, then Bro Splits might work (again depending on the details of the training program).

If your goal is to build useful strength as fast as possible without wasting time, then Bro Splits do not work. This is especially true of routines where a given muscle group is only targeted once per week.

The problem with isolation exercises is that we do not activate our muscles in isolation when performing normal movement patterns. When moving our bodies and exerting force against external resistances, we activate multiple muscle groups at the same time. To stand up, we activate our quads, our hamstrings, our hips, our calves, and our back. To pull something off a shelf, we activate our biceps, our triceps, our shoulders, our abs, our back, our quads, our hamstrings, etc. Normal human movement patterns always involve multiple muscle groups working in concert. When trying to maximize useful strength, all muscles involved in the movement pattern need to be strengthened. Otherwise, the weakest link will limit useful strength. The problem in trying to accomplish this strictly with isolation exercises is that it's basically impossible to know how much to strengthen each muscle group relative to the others.

Let's say your goal is to be able to lift 100 lbs from your chest over your head. How strong do your various muscle groups need to be in isolation in order to achieve that goal? How much weight should you be using with tricep extensions in order to achieve that goal? How much weight should you be pulling on the deltoid machine in order to achieve that goal? How much should you be pulling on the pec fly machine in order to achieve that goal? It's essentially impossible to answer these questions.

How strong should your triceps be relative to your biceps in order for the two muscle groups to be in balance? How strong should your quads be relative to your hamstrings in order for the two muscle groups to be in balance?

Attempting to build useful strength strictly with isolation exercises is essentially impossible, because it's impossible to know how strong each muscle group needs to be relative to its complementary or supporting muscle groups, and it is often difficult to mimic useful movement patterns using isolation exercises.

The most effective way to build useful strength is with compound movements. There's no guesswork needed to determine how to balance complementary or supporting muscle groups. All muscles involved get trained at the same time and to the degree necessary to complete the movement in question. The movement patterns are also natural. People squat. People pick things up off the floor. People lift things over their head. People push things. The compound lifts that mimic these movements are the most effective way to increase useful strength.

As for why the "lean, athletic" types prefer Bro Splits?

Well, I'd argue that looking athletic and being athletic are not the same thing. What you're probably observing is people with low bodyfat who are trying to enhance the aesthetics of specific muscle groups. But they are probably not very strong, and if they're athletic, it's despite their Bro Split training regimen, not because of it. But Bro Splits certainly could work for them, if their goal is to gain some hypertrophy in specific muscle groups.

The most effective way to increase general strength, for anyone of any age, is with compound barbell lifts (squat, deadlift, press, bench).

Are split routines in general bad? No, they have their place. Split routines are a perfectly legitimate (and effective) way to train around scheduling difficulties. Training three times per week is ideal, because it maximizes rest between lifting days. The downside of this is that each lifting session will get to be quite long, especially as the rest times between sets increase. A split routine typically separates upper-body-targeted lifts from whole-body lifts, and has the trainee lifting more days per week. The upside is that this shortens each session to a more manageable length. The downside is that rest between sessions is less than ideal. When you do bench and press one day and squats and deadlifts the next, your back didn't really get complete rest on the first day like it would if you were taking a complete day of rest prior to a lifting day.


The question was "why do people focus on one muscle group a day", not "why should I not focus on one muscle group a day", so I'll answer that.

One of the most essential parts that building muscle is having rest days. The idea of focusing on one muscle group at a time is that each day you are resting the muscles you worked the previous day and working out a new group of muscles.

Before I started working out 1-2 muscle groups in a day, I knew nothing at all about how to build muscle. I would usually find some crappy full-body routine and try to do that every day. The result was usually a week of improvement followed by two weeks of steadily getting worse as I didn't give my muscles time to recover, then giving up in frustration. Switching to a more focused routine allowed me to actually improve.


It depends on what you mean by "don't work".

Here is a study that looks at weightlifting routines' effects on body mass / strength. It concludes that "both bodybuilding- and powerlifting-type training promote similar increases in muscular size, but powerlifting-type training is superior for enhancing maximal strength".

The bro-split is more of a bodybuilding routine. It isn't going to be as good at building strength, but if your goal is only to increase the size of your muscles (hypertrophy) then it will work as well as most other routines of similar volume. Also by focusing on individual muscle groups more, the "stabilizing muscles" aren't going to be worked as much: if my routine focuses on bench/squats/deadlifts then my abs are getting work constantly which I won't be getting much of in a bro-split.

Bro-splits work fine for the goal of looking better. But you'd achieve the same appearance change with additional health benefits from getting stronger if you used a strength based program.


Until your CNS and lumbar discs tell you otherwise…

Upper lower 4 workouts a week work great for me. Plenty of rest days and twice a week each muscle gets quality stimulation.

I used to do bro split, all those leg sets in one session each week made it unbearable to recover from. No junk volume and legs never get sore.

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