June 07, 2024 3 min read

By Shane Robert

The “bro-split” or, as it has recently become known, the “pro-split” is the training split that most people come into the gym with some awareness of, likely a result of the occasional muscle magazine perusal or portrayal in media. This split breaks the body down into muscles and devotes an entire training day to that muscle. We get the famous “don’t skip leg day” memes from this concept. 

Although it is often viewed as one muscle per day, in reality, it is often more than one muscle but worked in groups viewed as muscles. The leg day example above illustrates this perfectly — you are working quads, hamstrings, calves, maybe glutes. That’s a lot of different muscles, even though they are all part of the leg. Arms are often viewed as one and trained together, as is back, even though in reality it is many different muscles with differing purposes. 

An example of a bro split might look like the following: 

DAY 1: Chest
DAY 2: Back
DAY 3: Legs
DAY 4: Shoulders
DAY 5: Arms

Where the days fall is largely irrelevant. Spacing chest and shoulders apart is probably a good idea to prevent carryover fatigue, though I have seen that done many times. Some lifters will split legs between quads and hamstrings for a six-day split. The essence is that each body part gets its own day devoted to training. That means it is likely getting trained only once per week and will require a tremendous amount of volume in that one single session (literally all of the weekly volume needed for the muscle). The advantage of training a single muscle group is that you can, in theory, do this without too much undo fatigue. 

Many professional bodybuilders have utilized this type of split and continue to do so. Putting aside the * ahem * assistance that they have, I won’t say that it is useless as it clearly works for them. However, it is probably one of the lower-tier options for setting up a training plan. As long as training is matched for volume (number of low RIR sets per week), hypertrophy seems to be about the same, although there is evidence that a frequency of twice per week is slightly superior to once a week, even when volume-matched. Where there is a large disparity is in strength.

When training for strength, a higher frequency, or practice, of a specific lift results in greater neurological efficiency. In other words, you simply get better at that movement. In addition, greater frequency allows for heavier loads to be used. If a lifter needs 30 sets per week to hit their maximal recoverable volume, they are going to have a hard time lifting heavy enough loads to induce strength adaptation on the 26-30th set of a single workout. This is known as junk volume. On the other hand, if they space that volume between 2-4 training days, they are likely to be able to use loads much closer to their true limit, not simply their fatigued limit. 

Intense focus on the muscle being worked
Probably fine for purely hypertrophy training
Ensures a muscle is thoroughly trained
Causes lots of soreness (means nothing, but some people like that)

Terrible for strength
Excessive muscle damage
Unbalanced training (does chest or the shoulders need a whole day to themselves?)
Tends to junk volume
Very upper body dominant

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