One detail of resistance training that is not often talked about is how long you rest between sets, also known as inter-set rest intervals.
Just to make sure everyone is on the same page with what we are talking about let’s start with an example.
Say you are following a training program and it calls for you to do 10 reps of a dumbbell bicep curl for 3 sets where at the 10th rep you are about 2 reps shy of failure.
This basically means you are going to pick a weight and do 10 reps of a bicep curl so that at the 10th rep you could probably do 2 more reps but wouldn’t be able to do 3 more. You would then repeat that protocol 3 times.
The question we are going to address here is how long should you rest between the 3 sets of 10 reps.
Should you rest 20 seconds, 1 minute, 2 minutes, 6 minutes?
How do you know what to do?
I often find that the rest intervals someone will naturally select depends on their training history.
If you are someone who has an endurance background or has been doing a lot of high intensity interval training (HIIT) you are likely going to naturally drift towards shorter rest intervals between sets.
To you it probably feels “unnatural” or like you are not getting a good workout if you are just sitting around not doing anything, so you want to get back to exercising as soon as possible.
On the other end of the spectrum if you have been doing a lot of power lifting, where the ultimate goal is to lift as much weight as possible, you are going to naturally want to rest several minutes between sets and select longer rest intervals.
For this person most of their training has been around lifting as much weight as possible and they realize the longer the rest they take the more weight they can lift.
There is a reason why powerlifters like to rest longer. To find out why let’s take a look at a recent study that compared 1 and 3 minute rest intervals.
This study was done on female lifters. Both groups did 10 reps to failure of chest press and leg press for 4 sets. The difference between the groups was one group rested for 1 minute between sets and the other group rested for 3 minutes between sets.
Here is what the study protocol looked like
What researchers found was that there was a significant decrease in total volume lifted for the group of females that only rested for 1 minute.
What does that mean?
It means that for sets 2, 3, and 4, the group that rested 1 minute did fewer reps than the group that rested 3 minutes. This table shows the percentage of change for sets 2, 3, and 4 for both groups
At the end of the day when you do less volume you will more than likely see less gains in muscle and strength.
This is why the powerlifter tends to select for longer rest intervals, it’s maximizing their strength, and that is their ultimate goal!
If you are wondering what other evidence there is out there on the topic of long versus short rest intervals…well there are quite a few studies that support longer rest intervals over shorter rest intervals.
You will also notice that some of these studies used 5 minute rest intervals, one even used 8 minute rest intervals.
So where does this leave us, is longer rest intervals always better? Should we be resting 10 minutes between sets?
While we don’t have studies showing this, it’s likely that as the rest interval increases in duration that the increase in volume is going to get smaller.
In other words increasing your rest interval from 1 minute to 3 minutes might show a pretty big jump in overall training volume. An increase from 3 to 5 minutes might be a smaller increase, an increase from 5 to 7 minutes might be even smaller, an increase from 7 to 9 minutes even smaller…eventually the cost, in this case time, will outweigh the benefit.
In addition, decreasing rest intervals can be another source of stimulus to increase the training effect. If you can do the same volume of work overall but do it in less time, you are improving density, and by doing so you are challenging your muscles just as if you were increasing volume. I talked about the concept of density in my resistance training prescription post if you want to learn more. Be careful though because you don’t want to increase density to the point where your volume decreases (as it did in the study above), that is going to have negative effects.
Lets now try and answer the question we started with…
What is the optimal rest interval when resistance training?
For major compound movements (deadlift, squat, bench press, overhead press, rows) resting 3-5 minutes appears to be a sweet spot. For accessory and single joint exercises, 1-3 minutes seems to be adequate.
Now I don’t think you need to be starting and stopping a stopwatch throughout your workout to make sure you are hitting these numbers spot on. You can certainly gauge your rest based on your performance.
If you start to see the number of reps you can complete drop off from set to set, start increasing your rest periods.
If you are feeling really good on any given day and you feel like you can shorten the rest and improve density go ahead and rest 2 minutes after your set of squats.
Remember research provides some general guidelines, “mesearch” is where we find what works best for YOU!
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