Updated: Jan 10
A lot of factors come into play when trying to grow bigger arms.
First, let's cover the muscle groups that make up your arm.
Starting with the bicep, which is made up of the short (posterior) and long (Interior) heads.
In order to grow big biceps, you must give them both the proper amount of training.
Since your biceps are a much smaller muscle group, then say your legs or back.
They require extra attention, using multiple curl variations to target the biceps differently.
The more supinated (underhand) your grip, the more your short head is recruited.
The more neutral your grip, the more your long head is recruited.
I personally have a day specifically for arms once a week.
But, because they recover so fast, don't be shy to train them twice.
Outside of training them alone, try linking them with your next back day.
Now onto the largest muscle group of your arms, the tricep.