Like any normal person, I was excited when I started going to the gym. I had a friend with me and we were guided by a trainer. For the first 2 months he'd tell us what exercise to perform everyday. We were completely dependent on what this trainer advised. It wasn't after the 2 months that my friend stopped going to the gym and the trainer quit his job. Me being in that uncomfortable zone, didn't want to ask the new trainer for help. So I decided to lookup the internet. This is when I realized what I had been doing was the bro split. I also figured why I hadn't grown as much as I should have. Them newbie gains did come but not as much as I had hoped.
What is the bro split ?
This is the old traditional routine that every gym bro out there would be practicing. Monday is chest and so on. Everyday you train one body part. Its usually a 5 day split with Chest, back, shoulders, arms and legs. Most people, don't even have fixed exercises to perform but instead walk in the gym and decide what exercises they want to do. It's usually a pick and choose process which adds to the non-optimal nature of the bro split.
The bro split over trains your muscles
So basically when you train one body part everyday, you perform around 7 different exercises with at-least 3 sets each. That means a total of 21 sets on one body part. This is a recipe for disaster as this is too much volume for one workout session. This often leads to fatigue and over-training. By the end of the workout your muscle is already sore and your pushing it way beyond then it is supposed to be put through. This in-turn limits muscle hypertrophy and may even make you lose gains instead.
It doesn't allow you to train each muscle group at-least twice a week.
Now it is proven by studies, that for muscles to have optimum growth in size and strength it has to be trained at-least twice a week with moderate volume. This however, isn't possible with the bro split. You train a muscle group only once over the week. Hence this isn't efficient as a training routine. Moreover, muscles like legs need to be trained with more intensity and volume compare to other parts like your arms. Your arms usually have only isolation exercises, but your legs incorporate more compound exercises. You should always be performing more compound lifts compared to your isolation exercises.
You'll be better of pairing your arms with your chest and back days as your arms already work considerably on these days as side muscles.
Hence you'll be better of pairing up muscle groups and following a push pull legs routine instead. The bro split will obviously give you muscle, but not as much as you can have following a better routine. The results won't be as good in both the strength and hypertrophy department. The only advantage I see with the bro split is recovery time is increased. However, when you're already over-training your muscles and then aren't training them enough over the week, there wont be as many pros of that recovery. Stay aesthetic and stay safe.