“You NEED to rest at least 2-3 minutes! You’re killing your gains if you’re not resting enough!”

Have you heard such claims before?

If you have, you’re not alone. I hear it several times per week.

Does the body of evidence we have currently suggest that this is true?

Short Answer

No.

Long answer

In 2017, Grgic and colleagues investigated the evidence on short vs long inter-set rest intervals in a systematic review.

Based on the studies they utilized - of which there were 6 - the researchers found that short and long rest intervals can be useful when maximizing muscle gain.

Hooray! Both work (and no one should be surprised by this)!

However, the researchers concluded with a slight bias toward longer rest intervals, suggesting that they may be more effective for muscle growth.

Why might longer rest periods be more effective?

The studies included in Grgic’s systematic review compared short and long rest intervals on a per-set basis.

Here’s an example of what this would look like:

Group A: performs 3 sets of an exercise with 2 minutes of rest between sets.

Group B: performs 3 sets of an exercise with 45 seconds of rest between sets.

Based on this mode of comparison, it should be obvious why group A might see more gains than group B - they can use more weight for more reps because they’re more recovered going into every set.

Imagine you created a study that compared inter-set rest times during sprinting which had the following protocol:

Group A: performs 3 40-yard sprints with 5 minutes of rest between sprints.

Group B: performs 3 40-yard sprints with 30 seconds of rest between sprints.

Which group, on average, would see less of a drop-off in sprint speed between sets?

Of course, this is a more extreme example, but it proves the point: group A would have the advantage because they’d likely be fully recovered by the time they performed subsequent sprints.

The same applies to lifting if you compare longer and shorter rest on a per-set basis.

If you rest longer, you’ll recover more and your performance on each set will be higher (you can lift more weight for more reps).

However, this “per-set basis” strategy does not reflect the nature of how a training session operates on a practical level.

Why?

Because if you rest for less time, you have more time to perform more sets!

Refer back to our first comparison:

Group A: performs 3 sets of an exercise with 2 minutes of rest between sets.

Group B: performs 3 sets of an exercise with 45 seconds of rest between sets.

Group A rests for a total of 6 minutes. Group B rests for a total of 2.25 minutes.

This leaves group B with an additional 3.75 minutes (not accounting for the length of each set)!

In other words, group B has extra time because they’re resting less. This means group B can perform more total sets in a similar time as group A!

So, in a practical training scenario, group B could perform more sets than group A, and we’d likely see different outcomes based on this approach.

That’s exactly what two studies - one from 2014, another from 2022 - found.

These two studies equated for volume load - sets x reps x weight - and found no significant differences in hypertrophy between groups that rested shorter versus longer intervals.

In other words, the groups that rested less time did more total sets with the additional time they had. These extra sets closed the gap in muscle growth between short vs long rest groups.

Two more studies indirectly support the notion that volume load equation between training protocols yield similar muscle growth responses: one is a meta-analysis from 2022 that compared drop set and traditional set protocols, and another compared myo-rep and traditional set protocols.

Drop set and myo-rep training protocols are known as “intensifier” strategies that decrease rest dramatically.

When you perform a drop set, you perform your first set at or close to failure, then immediately lower the weight you’re using and perform another set. You can do multiple drop sets in a row by lowering the weight each time you approximate muscle failure so that you can continue to do subsequent sets with little to no rest.

When you perform a myo-rep set, you perform your first set close to failure, typically in the 8-15 rep range. After resting 10-20 seconds, you perform another set with the same weight, only performing 3-5 reps. Because you don’t allow for full recovery between sets, you begin in a pre-fatigued state that allows you to come close to muscle failure sooner on subsequent sets.

Drop sets and myo reps were shown to be equally effective for muscle growth compared to traditional “straight sets” wherein you allow for sufficient recovery between sets (2-3 minutes).

This further supports the notion that resting less can be equally as effective for muscle growth as long as you volume-load-equate between protocols.

What’s the Catch?

This field of research is still in its infancy. Only certain muscles have been tested under different conditions and these comparisons may not apply to all scenarios in all people.

In addition, while groups that rested less received similar muscle growth to groups that rested more (when volume load equating), groups that rested more saw greater improvements in strength.

This implies that resting more may have more utility, but I’m not convinced that the difference matters much for the average lifter in the long run (you get stronger even when resting less, too).

If your goals are specific to hypertrophy, I’d recommend resting however long you see fit.

If you enjoy resting for less time, do more sets on average. If you enjoy resting more, do fewer sets on average.

In addition, you don’t need to utilize the same rest protocol for all exercises.

Some exercises - such as squats and deadlifts - lend better to longer rest periods because your cardiovascular system (as opposed to local muscle fatigue) may be rate-limiting.

Alternatively, some exercises - isolation movements like curls, leg extensions, etc. - may lend better to shorter rest periods because your cardiovascular system is unlikely to rate-limit the effort.

My advice: choose the rest protocol that feels right to you on a per-exercise basis. There is no “one size fits all” approach to rest periods, at least not based on what we currently understand.