A little while ago, I touched on a video about a new research at the time that tested the
difference in muscle growth between 1 and 3 minutes of rest between sets.
In short, 3 minutes of rest was deemed superior because ultimately the additional recovery
time allowed for a larger total volume workload.
Now this year, in 2017, a new systematic review has been published, outlining all of the available
studies up to this point that touches on rest between sets.
All studies that met the following criteria were accepted into review:
1, it was peer-reviewed and in English.
2, it compared exercises using a rest interval less than 60 seconds to a rest interval greater
than 60 seconds.
3, it used at least one method of measuring changes in muscle mass
4, the experiment was longer than four weeks with at least 2 training sessions per week
And 5, the subjects were deemed healthy and injury-free
The criteria points are heavily restrictive but for good reason.
The last thing we want is to have other non-rest factors in training that might sway the results.
However, it also means fewer studies are acceptable.
1,115 studies met the researcher’s initial screening.
But after applying criteria eligibility, the number boiled all the way down to 6 studies,
including the one analyzed in the older video.
With such a small field of studies to analyze, the information has to be cautiously interpreted.
Knowing this, we still have to consider any factor outside of rest that might reflect
on the results, such as trained versus untrained individuals, the type of exercise, and the
intensity of the training.
But if we just look at the surface, the research reviewers found that results tend to slightly
favor by a few percentage points using a longer rest of 60 seconds or more between sets than
anything shorter.
The main contributor to this finding is that resting more simply allows you to lift a higher
total volume by the end of your session, just like the findings of the past video.
But… before you run off and start doing 2 to 3-minute breaks between all of your sets,
we first need to revisit those other factors mentioned earlier.
When it comes to the trained versus untrained person, it almost seems like a guarantee that
if you already have a few years of lifting under your belt, then you will benefit from
more rest.
But, if you’re just starting off or have maybe a few months to a year of training,
then any amount of rest can elicit a good amount of growth, perhaps due to the underlying
benefit of newbie gains.
Another factor is the intensity of the workout.
If the program you’re using doesn’t push you close to muscular failure or the weight
you’re using isn’t all too heavy, then shorter rest can work just fine.
In fact, there might a benefit of using shorter rests with a lower load and a higher rep scheme,
since there will be greater metabolite build-up of lactate, hydrogen ions, and inorganic phosphate,
which have been observed to increase muscle growth signaling.
On top of that, shorter rest intervals mean less time for the muscle to recover before
lifting again, which can heighten motor unit recruitment and promote the development of
the “muscle pump.”
However, if you’re lifting heavy, then once again, the research favors more rest between
sets.
Finally, when we dissect the researcher further, it seems that longer rest intervals benefit
multi-joint compound movements the most, such as squats and deadlifts.
Being that such exercises employ a high degree of muscle groups, total body fatigue can accumulate
much quicker, thus require more rest.
However, for more isolated, single-joint movements, like the bicep curl and side raises, the research
seems pretty split on the amount of rest you need.
One of the reviewed study noted no significant differences in hypertrophy when employing
either a 30-second or 3-minute rest interval when training with the bicep curl.
Now, as we can see, the answer isn’t so cut-and-dry as it initially was for favoring
longer rest.
Shorter rest intervals do have its place when it comes to muscle growth, too.
In fact, the researchers drew up this hypothetical graphic that gives credence to deploying both
rest intervals.
As we see here, shorter rest hypothetically benefits muscle growth by maintaining high
levels of metabolic stress.
Longer rest, on the other hand, can hypothetically benefit a greater deal of mechanical tension
and muscle damage from utilizing greater volume and intensities.
So now let’s wrap things up: If your goal is to completely maximize muscle hypertrophy,
then you’re probably best off deploying an inter-set rest interval between 1 to 3
minutes.
But, bear in mind, that the benefit isn’t all that substantial compared to using less
rest, and you need to consider that resting more will increase the total duration of your
entire session.
If you can only muster 45 minutes to an hour of gym time per session, then shorter rest
intervals are better for you.
Ultimately, you should aim for using both short and long rest intervals.
The researchers themselves advise spending the first part of your session on multi-joint
heavy movements while using longer rests.
After that, you can focus on isolation single-joint exercises with shorter rests.
For now, we still have to wait for more research to make a definitive claim as to exactly how
much rest you should take between sets.
At the end of the day, it’s only one part of your entire program.
Try out the suggestions and see if it works for you!
How much rest between sets do you think is best?
Share your thoughts in the comments!
As always, thank you for watching!