If you’ve been lifting weights for a while, you’ve probably come across programming described as “sibling splits”—a training method that focuses on one muscle group per workout. You’ll also see sibling splits referred to as body split workouts.
Bro splits came to prominence in the 1960s thanks to bodybuilders like Arnold Schwarzenegger, Franco Columbu, and Frank Zane, who used body-centered workouts to pack on slabs of muscle. Joe Weider helped popularize splits among regular joes by publishing body split routines in his fitness magazines. Brother splits became the de facto training method of most bodybuilders in the latter half of the 20th century. It’s believed that by devoting the entirety of a workout to a single body part, you could blast it with a ton of muscle-building stimulus while giving your muscles plenty of time to recover before you train them again.
But starting in the 2000s, you started to see some pushback against the sibling split. The biggest criticism leveled at split training is that because you trained a muscle group so infrequently (often only once a week), you weren’t stimulating the muscle enough to initiate muscle growth or increase strength. These days, the efficacy of sibling separation can be the source of lively debate on the interwebs.
So what’s up with sibling splits? Are they effective or just a holdover from bodybuilding’s past? To clear up this confusion about sibling separation and help you figure out whether you should use it for your programming, I spoke with Greg Nukols from Stronger Than Sciencean online publication that analyzes the scientific literature on education and nutrition.
What exactly is a Bro Split?
Bro splits are classically defined as programming where you focus on a single area of the body in a single workout.
A typical sibling separation program might look like this:
- Monday: Chest
- Tuesday: Return
- Wednesday: Shoulders
- Thursday: Legs
- Friday: Weapons
- Saturday: Rest
- Sunday: Rest
Greg pointed out that there is some debate about what constitutes a sibling division. “You could think of a sibling split as any programming where you don’t do full-body workouts. So classic push, pull, leg program it could be a fraternal split because you’re not training the whole body in one workout,” he told me.
Arnold Schwarzenegger is often featured there as a bodybuilder who used brother splits to build a strong physique. But if you look at his programming, he didn’t focus on a single body part in his daily workouts. His breakdown looked like this:
- Monday: Chest, Back, Abs
- Tuesday: Shoulders, Biceps, Triceps, Forearms, Abs
- Wednesday: Legs, calves, abs
- Thursday: Chest, Back, Abs.
- Friday: Shoulders, Biceps, Triceps, Forearms, Abs
- Saturday: Legs, calves, abs
- Sunday: Rest
So he was working multiple body parts in a single workout, but it’s considered by many to be a sibling split.
For this article, we’ll use the classic definition of a split: a program where you train one muscle group in a single weekly workout.
Are Bro Splits Effective at Building Muscle and Strength?
As mentioned above, the brothers were popular among bodybuilders in the second half of the 20th century. However, in the early 21st century, there was some pushback against sibling splits because research showed that training muscles more often than once a week could lead to more strength and muscle growth.
For example, Greg mentioned that a 2016 meta-analysis suggested that training the muscles at least twice a week was more effective in increasing muscle growth than training only once a week. Research has also shown that training muscles more than once a week increases strength.
So it seems that sibling splits are less effective at building muscle and strength, right?
Well, a 2020 meta-analysis found no statistically significant difference in muscle growth when training frequencies ranged from one to four times per week, provided total volume was equal.
Basically, this study showed that as long as you did the same volume for a body part in a week, it didn’t matter if you did all of that volume in a single workout or split it up into two or three workouts during the week.
So you could do a split leg sibling workout and do 20 total leg sets in one workout, or you could split those 20 sets into two different workouts and do 10 sets one day and 10 sets the other. You would get about the same results.
Greg noted that despite the 2020 meta-analysis, there is still research showing that training a muscle group more than once a week could provide a small advantage in muscle growth and strength.
(For a deep dive into the research on training frequency, check out Greg’s articles frequency and muscle growth and frequency and power.)
So what’s the bottom line?
Greg sums it up like this:
“I still think the balance of evidence suggests that higher training frequencies might be a bit more effective than sibling splits, but sibling splits are still fine. And for most people, they probably wouldn’t even notice a difference between the results of the two types of programming.”
Practical Benefits of Bro Splits
So as long as you get enough volume, splits can be effective in building muscle and increasing strength. How do you decide if sibling separations are right for you?
Greg highlighted the following practical benefits of separating siblings:
- Enjoyable: Some athletes simply enjoy the concentrated intensity of hammering one muscle group per session. It’s simple and focused. This resonated with me. I did a classic split brother workout a long time ago and loved it. It was fun to spend an hour just after my biceps and triceps. I loved the pump I got after these workouts.
- More time to recover: Bro splits offer more recovery time since you only train one body part once a week. A lot of people dread leg day, so they love the fact that they can hit their legs hard in just one workout and then not have to worry about training them again for a week.
- Joint-Friendly for older lifters: Anecdotally, Greg has noticed that some lifters in their 40s and beyond report better joint recovery with lower frequency training. Again, this comes down to the fact that you’re only training one muscle group once a week.
- Special Sports Programming: If you’re a runner or into another sport, bro splits can allow you to schedule your lifting around competition or sport-specific training. For example, if you have a 5K race on Saturday, you can do your strength training on your leg day on Monday, giving your leg muscles enough time to recover before the race.
Possible cons to Bro Split
- Time commitment: Traditional sibling splits often require 5-6 gym sessions per week. So if you don’t have time to train for an hour five to six times a week, sibling splits probably aren’t for you.
- Risk of injury: Greg noted that, theoretically, doing too much volume for a single muscle group in a single session could potentially increase the risk of acute fatigue injuries.
Sibling split training sample
Thinking of trying a split workout bro? Here is a sample program to use:
Monday: Chest day
- Bench Press: 3 sets x 10 reps
- Cable Flys: 3×10
- Incline DB Bench Press: 3×10
- Dips: 3xAMRAP (as many reps as possible)
- Push-ups: 3xAMRAP
Tuesday: Leg day
- Bar Squat: 3×10
- Romanian Deadlift: 3×10
- Hack Squat: 3×10
- Leg curls: 3×10
- Leg Extensions: 3×10
- Calf Raises: 3×10
Wednesday: Shoulder day
- Shoulder press: 3×10
- Lateral Raises: 3×10
- DB Seated Shoulder Press: 3×10
- Dumbbell bent-over deadlift: 3×10
- Face Pull: 3×10
Thursday: Return
- Deadlift: 3×10
- Lat Pulldown: 3×10
- Barbell Row: 3×10
- Pulls: 3xAMRAP
Friday: Armament Day
- Bar Biceps Curl: 3×10
- Rolling triceps extensions: 3×10
- Dumbbell incline curls: 3×10
- Rope Pushdown: 3×10
- Hammer Curls: 3×10
- Dips: 3xAMRAP
Conclusion
Bro splits can be an effective training method, especially if you enjoy them. While the latest research suggests that higher frequencies may offer a slight advantage, the difference is probably negligible for most lifters. The most important factors remain consistency, proper volume, and progressive overload — no matter how you break up your training.
Remember, the best training split is one you can stick to consistently. If you like sibling divisions and are making progress, you don’t need to change based on small theoretical tweaks. If you don’t like the way strength training is organized today, then try bro splits.
