Last week I pointed at a new exercise position stand from the American College of Sports Medicine (ACSM) and used it to argue that the boring fundamentals beat the fine details in terms of affecting results.
Today’s tip is based on the same piece and covers a variable that doesn’t purely belong in either category (i.e. fundamentals or details). Among the things listed in the ACSM position stand as not affecting strength development, right next to machines versus free weights and what time of day you train, was how long you rest between sets.
That’s true of the research they pooled. It’s also incomplete, and the systematic review their finding rests on says so itself: one to two minutes of rest between sets is enough to maximize strength gains if you’re new to lifting, while rest periods longer than two minutes are what maximize them in people who already lift. (I’d also suggest that what you’re specifically doing makes a difference in how much rest you need to maximize benefits.)
In other words, inter-set rest is a fine detail—right up until it becomes a fundamental.
Goal and effort determine rest
At the gym, I regularly tell members that I’d rather see them do fewer good-quality reps than more poor-quality ones—within a single set and across a session. Technical ability aside, what determines which kind of reps you get is how much the last set cost you and how long you waited afterward.
Which means the more useful first question isn’t “how long should I rest”, but rather “how much effort did that last set take?”
Ultimately, your answer will direct you toward one of three distinct situations:
The set was submaximal—rest one to two minutes, perhaps less
This is a set you finished with relative ease. Light and moderate days, technique practice, moderate weights with three or more reps still in the tank, and—what often surprises people—heavy weights for low reps, where you stop at half or fewer of the reps you could have done.
Since you didn’t spend much on the “effort” front, you also don’t need to spend much on the “wait” front before lifting again.
Which explains why “heavier means rest longer” isn’t the hard and fast rule. A single rep at 85% of 1RM (the heaviest weight you could lift for only a single rep) and a hard set of five at 85% are the same weight but completely different events. What a set costs you depends on the weight, the reps, and how close you took it to your limit—not the weight in isolation.
Ladders live in this bucket, and they’re the best answer I know for anyone who “doesn’t have time to stand around”. (If you’re unfamiliar, a ladder is a series of sets of increasing reps with rest between sets, which is started again from the beginning after completing the final rung. For example, 1-2-3, 2-4-6-8-10, or 5-10-15-20.) Every rung stops short of what you could do—by quite a lot on the lower rungs—so you never dig a hole that takes multiple minutes to climb out of. That’s the part that saves the time: because no single rung costs much, the rest between them stays short, and you accumulate a lot of quality reps in very little of it.
If you’re newer to lifting, this is the only one of the three “rest buckets” you need. Not because you’re getting the beginner version of the advice, but because every set you should be doing as a beginner belongs here.
Yes, you have goals like getting stronger, building endurance, changing your body composition, or some combination along with other objectives. But the skill that produces all of those results, at this stage, is learning how to move well and how to gradually handle heavier weight. Until you’ve practiced for a while, going beyond this level of effort is neither the safest thing nor even necessary—adding exercise to a routine that didn’t yet have it is itself the stimulus. Strength, endurance, work capacity, and body composition (with appropriate nutrition changes) improve because you’re doing something, which is what last week’s tip was about.
The set was maximal or near-maximal—rest three to five minutes, possibly more
This is a set you finished with very little left: zero to two reps in reserve. Usually that means a heavy weight, 80% of 1RM or above, though what defines it is how close you came to your limit rather than the number on the bar (or kettlebell, sandbag, etc.).
Strength is largely a skill, and skills are best practiced fresh.
But “fresh” isn’t only about how you subjectively feel. It’s a factor of muscular fatigue and how much the energy system utilized during the set was depleted. As I mentioned in that tip, the general rule is that the closer we come to exhausting an energy system, the longer it takes to recover—and three to five minutes is potentially still on the shorter end.
The practical catch is that you’ll feel ready well before you are. Your breathing and heart rate will recover quickly, but your ability to produce the same—or nearly the same—amount of force will take considerably longer. If you use “I’ve caught my breath” or “I can’t feel my heart pounding out of my throat anymore” as the signal to start the next set, you’ll consistently start too early. While you may still be able to lift the weight again for some reps, you’ll hit the wall, lose good form, or (worse) both far sooner than if you’d waited longer.
The better signal—although it’ll take some practice to get right—is to track your technique from one set to the next. If anything changes, rest an extra minute from the prior set’s rest period before lifting again.
Recovery is incomplete on purpose—rest less than that set would otherwise need
Hypertrophy (muscle growth) and some endurance work fall into this bucket.
What puts a set here isn’t the weight, reps, or, by extension, effort—plenty of hypertrophy sets would look submaximal on paper. It’s that the leftover fatigue is doing the training. You’re starting the next set before you’re ready because being not-quite-ready is the stimulus.
So the rest can be deliberately shorter than what that same set would need to recover fully (based on the first two buckets).
The guardrail is the same one as everywhere else, just (slightly) looser: technique can slide a little, but it still can’t fall apart. Working while fatigued is the goal; working poorly isn’t.
Putting it into practice
I’ve said before that modern fitness puts too much emphasis on cardio. (Not that it’s unimportant—it’s just not all-important.) One consequence shows up in rest periods: as I noted in that tip, a lot of people think “more cardio” means higher reps and less rest. So the third bucket becomes the default, no matter which bucket the set actually belonged in.
Since the effects will show up in your results, that’s a mistake worth avoiding.
Here are a few questions to help you steer clear:
- What’s your goal?
- How much effort are your sets costing you?
- Do your rest periods generally align with the combination of the two? Alternatively, do most of the reps in the sets later in your sessions look similar to those from earlier in that session?
Particularly if your answer to the final bullet’s questions is “no”, you’d likely benefit from an extra minute of daydreaming (or boredom) before getting back to your next set.