Shorter rest between sets works just as well for small muscles like biceps as it does for big muscles like legs.

What we've found so far is that the evidence on whether longer rest intervals provide less hypertrophic benefit for smaller muscle groups compared to larger ones is nearly evenly split. Our analysis of the available research shows 46.0 assertions support the idea, while 49.0 refute it [1]. This means the current body of evidence does not clearly lean in either direction. We looked at what has been reported across studies and found that almost as many support the idea that longer rests (over 60 seconds) matter less for small-muscle exercises—like bicep curls or lateral raises—as oppose to multi-joint lifts like squats or bench presses, as those that contradict it [1]. Because the numbers are so close, we can’t say with any confidence that the effect is meaningfully different between exercise types based on muscle group size. Our current analysis shows there’s a near balance between support and refutation, which suggests uncertainty in the data. It’s possible that other factors—like training experience, volume, or intensity—might influence whether rest length matters more for some exercises than others. But based on what we've reviewed so far, we don’t have enough consistent evidence to make a general rule. This doesn’t mean the idea is wrong or right—it just means the data we’ve analyzed hasn’t settled the question. As more research becomes available, our understanding may shift. Practical takeaway: If you're choosing rest times, you might not need to worry more about muscle size involved in the exercise. For now, rest times can still be based on how you feel, your workout schedule, and what lets you keep good form and effort across sets.