I used this move in my prep to keep my arms bangin.
One thing I do not allow in my studio is for my clients to have jiggly arms.
If your arm is jiggly, you look old. I said it.  It doesn’t matter how old you are, so the trick is to keep it tight.

Use a plate at your gym. Keep your elbows tight to your ears and rep that hard.  Do 3-4 sets of 12.  I do not want to hear about you, bikini girl, lifting 5 pound plates.  Go get some big girl plates and get your work done.  Even if you start with only a few, drop your weight down and finish the set!