Do you really need to take upwards of 4–5 minutes between sets of your heaviest weights? The science might surprise you.

By Jimmy Peña, MS, CSCS

I’m not a fan of trick questions, but let’s see if you can get this one right. Assuming you’re taking both sets to failure, what’s more draining to perform: a set of your max weight for one rep, or a set of 12 reps? While the max-weight set obviously uses a heavier weight, it seems pretty obvious the set of 12 should be more demanding, right? But if that answer seems so easy, why then do we rest longer between sets for the heavy stuff and keep rest periods to a minimum for the high-rep sets? Something doesn’t seem right.

If you’re scratching your head, you’re not alone. More and more experts are doing the same because the subject of rest periods could be one of those areas where disagreement is also a breeding ground for breakthroughs. A show of hands to anyone who can relate to the following illustration: After you bust out a heavy set of 5–6 reps, you sit down and wait … and wait … and wait some more. Three, four, maybe even five minutes go by before you feel ready to get under the bar for another short set of five or fewer reps. Are you resting because you actually need all that recovery, because it’s just a very heavy weight or because someone told you?

RECAP ON RECOVERY

Let’s be clear: Rest periods are all about recovery time, but what’s the ideal recovery time based on a set’s relative weight (how many reps to failure)? Recovery time has everything to do with the replenishment of ATP — the energy inside our muscle cells. Reps of 1–6 rely mostly on stored ATP in the muscle fibers, which replenishes relatively quickly; in addition to stored ATP, doing 7–10 reps uses creatine phosphate (the form creatine takes in muscle cells to supply immediate energy) to a greater degree, which takes significantly longer to restock; and finally, sets of 10 reps and higher use even more creatine phosphate and rely on muscle glycogen levels, taking the longest of the three to replenish.

So if reps from 1–6 rely mostly on stored ATP, and stored ATP is quick to replenish, why do we rest so long between those heavy sets? Conversely, for sets of about 12 reps, why are we so quick to jump to the next set or exercise? Besides, you rest between sets not just to restore your energy systems but also to clear and flush by-products of fatigue from your system such as lactic acid. And those effects just happen to be most prominent during high-rep sets (the ones between which we rest the least.)

PAUSE ’n’ THINK

Think for a second about rest-pause training. As you know, rest-pause training has you hitting a heavy set but not going to complete failure. For example, you take a weight that would cause you to fail at around 6–7 reps but you stop at 3–4 reps. You rest about 15 seconds and then bust out another round of 3–4 reps. You repeat that sequence 4–6 times until you can’t fulfill the target 3–4 reps.

Now, for whatever reason, when we’re in the middle of a rest-pause set of heavy-duty repetitions, we find no harm or foul by giving our bodies very little rest, but when we isolate a straight set, we wait minutes on end before attacking the weight again. Imagine how many more reps and sets you could apply to each bodypart if you considered that each muscle group is fully recovered in a fraction of the time that it’s used to receiving. Add all of those sets together over the course of a few weeks and months and consider the kinds of gains you could possibly be missing out on.

MENTAL CASE

While you ponder that, consider the following: Are the prolonged rest periods between heavy sets completely mental? If the body is ready to go, what’s stopping us? Are the head games that we play before big lifts actually necessary or manufactured intensity? After all, we’ve all gone for some personal records and the bouts are over before we know it. Then we spend the next five minutes getting ready for the next attempt, one that’ll take fewer than five seconds to perform. There’s probably not a single weightlifter reading this paragraph who’d argue that the time spent getting their head ready for a lift was a waste of time, and this writer wouldn’t argue.
So are we only waiting for our mental stamina to recover? And if so, why would it take so long for us to gather the courage to attempt a lift that our body is ready for? Conversely, are we giving less mental effort before attempting lighter, higher-rep sets, even though physiologically our bodies need more time to replenish the systems responsible for it? If your muscle brain is baking, don’t worry. This is a debate that’s sure to continue long after you’ve moved on to the next exercise.

Ultimately, the long rest periods — whether they’re for super-heavy attempts or even moderate, hypertrophy loads — all add up to longer training sessions and fewer sets. The longer you spend in the gym, the higher your cortisol levels rise inside your cells, which can lead to decreases in size and strength. The risk is that while you rest a perfectly rested muscle, you could also be wasting precious training time and increasing your chances of cortisol-induced atrophy.

OVERLOAD YOUR JOURNAL

Now all that theorizing sounds fine and dandy, but how can we test those questions and theories without sacrificing size, strength and time. The challenge is this: Start keeping a journal. Write down your rest periods, your RMs, everything. From one week to the next, begin decreasing any rest periods that you feel might be too long to begin with. When you do so, try tacking on another set to increase total volume of work, all while journaling your mood, appetite, energy, and progress or lack thereof.

Remember, the overload principle is true; the body will change only according to the level at which it’s stressed. Each session and each week, you have to take bigger strides to achieve bigger success. Asking something different of your muscles is a way to shock them and overload them into growth. Manipulating your rest periods, despite what you’ve always “known” or done, might be exactly what saves you.

TIME TO RECOVER

How long does it take for a working muscle group to recover from a set that’s taken close to failure? It depends on the intensity (how many reps you do) as well as whether it’s a large or small muscle group.


REPS INTENSITY ENERGY SUPPLY TIME TO RECOVER
< 6 High Stored ATP in muscle cells Quick; less than 30 seconds
7–10 Moderate Stored ATP in muscle cells + Creatine Moderate; 45 seconds
> 10 Low-Moderate Stored ATP in muscle cells + Creatine phosphate + Muscle glycogen Takes longest of all to replenish; 60 seconds for small muscle groups to 180 seconds for larger ones.

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What a RUSHHHHHHHH!!!!!!!!