One of the most common pieces of gym advice is to rest at least 90 seconds between sets for optimal muscle growth. And while that recommendation is backed by solid research, it doesn’t always tell the full story.
In practice, I’ve found a more effective approach: using rest proxies, as popularized by RP Hypertrophy. Rather than relying solely on a stopwatch, RP’s method encourages lifters to run through a quick mental checklist before starting their next set. You don’t want to wait an arbitrary amount of time; you want to ensure that your body is ready to crush the next set.
Here are a few questions to ask yourself before beginning your next working set:
- Are you still breathing hard?
- Is the supporting (secondary) muscle group still fatigued?
- Are you mentally prepared to push hard again?
- Are you confident the target muscle can perform at least five high-quality reps?
That last one is especially important. Research shows that the 5–30 rep range is optimal for hypertrophy. So if your muscles are too fatigued to hit at least 5 clean reps, it’s a sign you haven’t recovered enough from your last set to stimulate growth effectively.
These types of real-time checks are often more useful than rigid rest times. They let you adapt to how your body is responding on that exact day, with that specific exercise.
Take squats, for example. Ninety seconds might not be enough. You could still be breathing hard, mentally drained, and your lower back might be more fatigued than your quads. In that case, resting 3–5 minutes may be the smarter move.
Now contrast that with lateral raises. There’s minimal systemic fatigue, very little secondary muscle involvement, and your mind is likely ready to go. You might feel fully recovered in 30–45 seconds—so why wait longer?
That said, fixed rest times do have value, especially for beginners. If you’re still learning to listen to your body, having set rest intervals can act as helpful guardrails while you gain experience. And if you’re short on time—training during a lunch break or in a rush—they can help keep your workout efficient and on schedule.
The key takeaway?
Over time, your body will give you clearer and clearer signals. Learning to listen is a skill—one that leads to smarter training and better results.
If you want to dive deeper, I highly recommend this video from RP Hypertrophy that explains the full concept of rest proxies:
Train hard. Rest smart. Grow stronger.
