Short Rest Periods for Biceps & Triceps
Too many coaches use universal rest periods for weight training exercises, like 2 or 3 minutes. This is a mistake. There's no value in taking long breaks with small muscle groups.
Seriously, if you're winded after a set of 8 reps on barbell curls your cardiovascular conditioning is a joke. If you do some Googling you'll find many studies that demonstrate increased hypertrophy from shorter rest periods. I'll let you do that on your own time, as this tip is more about "street knowledge."
Shorter rest periods for arm training...
Increase intensity: Shorter rest periods are simply another way of increasing intensity.
Increase blood flow: Shorter rest periods help you achieve more of a pump. Through the years I've found the best arm training results when I was also getting the best pumps. Proper nutrition, pre and intra-workout supplementation, and other factors also play a huge role, but I'm convinced that short rest breaks on arms will pump the heck out of them if you're using good form with a manageable weight.
So How Long Should Your Breaks Be?
Here are a few things you should try:
10-second breaks. Sprinkle these into your arm workouts on occasion. For example, do 4 sets of 8 reps with a 10-second break between each set of EZ-bar curls. It won't take much weight to annihilate your biceps. These are best used for shock.
30-second breaks. This is the rest interval I typically take when in pre-contest mode. It's enough time to recharge for your next set, but not so long that you lose focus. If you're alternating between biceps and triceps exercises, the timing should work itself out. Just go back and forth, banging out your sets.
45-second breaks. This is the standard rest time I use between sets of arms in the off-season. I don't see any reason to go past 45 seconds on any arm work. This is the maximum allotted rest break.
Note: I don't sit and actually time myself, nor should you once you've gone through a few workouts and become accustomed to a brisker pace. Autoregulation, right? It works.