Introduction

How long should you rest between each set you perform? This is a question that many people ask, and there is a lot of confusion and misinformation floating around in regards to the answer. Some people swear by shorter rest times, stating that it's better for bodybuilding styled training, others, especially powerlifters, say you should rest for as long as you need to be ready for your next set. So, who's right? Are there benefits to shorter rest periods or should you be resting a bit longer between sets? Let's dive in.

Rest periods used by different types of athletes

Old school bodybuilders commonly used much shorter rest periods. By using shorter rest periods, they were able to keep their muscles fatigued, maintain "the burn", and maintain pumps in their muscles (increased bloodblow). This was thought to cause more hypertrophy because the muscle always felt highly stimulated and much more fatigued overall. Because of this, they avoided very long rest periods that allowed the burning sensation in their muscles to subside and their pumps to fade, fearing this would reduce the effectiveness of their workouts

On the other hand, strength athletes have always used longer rest periods, because it allows the athlete to be prepared to give their maximum performance each set, which is extremely important for strength showcasing. When inadequate rest periods are taken, performance will take a large hit, leading to less weight lifted or less reps performed.

So who's right? Well, by the end of this article, you'll learn that surprisingly, they both are in the correct context!

Does inadequate rest affect muscle growth?

It's pretty clear that inadequate rest periods will negatively impact strength performance on subsequent sets because it is immediately evident when it happens, but what about for muscle growth, a process that takes much longer to realize?

First off, what exactly causes a muscle to grow?

It's important to understand what causes a muscle to grow before we begin to discuss rest periods. From years of study, research and meta-analysis, we now have a pretty clear understanding of what causes a muscle to grow. Without going into too much detail (beyond the scope of this particular article), the amount of "hard sets" you perform is what is most correlated with muscle hypertrophy. The more hard sets you perform, the more hypertrophy will occur. A "hard set" is any set that takes a muscle near failure and consists of at least 5 repetitions. To count as "near failure", a set must be taken within 3 or less reps shy of failure.

What does the research say about rest periods and hypertrophy?

Recent research is starting to paint a clearer picture. A new study [1] shows that when performance drops off due to inadequate rest, each set performed this way can build as much as 50% less muscle. This also means that for strength development, longer rest periods are important as well, because muscle growth is a large factor in building more strength. If you hinder muscle growth rates, you also hinder the rate at which you can build strength. It is important to note that research suggests that this is of larger concern for compound movements, and not for isolation exercises such as barbell curls.

Shorter rest periods for isolation movements does not seem to impact muscle growth rates (with some caveats). This is likely because you are using many muscle groups at once in a compound movement, and thus excessively short rest periods prevent some muscles from properly recovering between sets, hindering your ability to take muscles that are fully recovered close to failure. In addition, compound movements are intense on the cardiovascular system, so excessively short rest periods will cause you to stop a set early not because your muscles reached failure, but because your cardiovascular system is tired. On the contrary, isolation movements are not limited by many factors other than the muscle(s) being targeted, so they are less affected by short rest periods.

So strength athletes are actually spot on for using longer rest periods for their compound movements, which are the primary focus of their training. By resting longer, they allow themselves to produce maximal force per set and at the same time maximize training stimulus for all muscles involved in the movement. Bodybuilders were also onto something. While shorter rest periods are not necessary, bodybuilders were correct that they can safely get away with shorter rest periods on isolation movements, which are abundant in bodybuilding styled training. In fact, the shorter rest periods on smaller movements were beneficial because it allowed them to get in more total sets in a shorter amount of time.

Factors for deciding rest periods.

Deciding on proper rest times is slightly more complicated than it seems on the surface. There is no answer that will fit all individuals and all situations. However, we will touch on important factors that need considering, and then we'll have a check list of what to look for in order to decide whether you're resting long enough. 

To start, we must remember that for a set to stimulate muscle growth, the target muscle must be taken near failure. This means that the target muscle ITSELF must be the limiting factor when you stop a set, and nothing else. There are many things that can limit your ability to continue a set, and proper rest can be key to making sure that the only thing preventing you from continuing a set is the target muscle itself.

Below are the three main limiting factors for a set.

Cardiovascular endurance. Cardiovascular endurance is mainly a concern for compound movements. When finishing a hard set of an exercise such as squats, it is quite likely that you feel winded and need to rest not only because your muscles are fatigued, but because your overall body is fatigued, your heart rate is elevated and you're out of breath. If you don't allow yourself to rest long enough for your cardiovascular systems to recover and you attempt to perform another set, it is likely that you will have to stop your next set short, not because the muscles you are targeting have reached their limits, but because you're simply too winded and your cardiovascular system is still too taxed.

Synergistic muscles. When performing an exercise that targets multiple muscles, the muscle you want to target most may not always be the limiting factor if you don't rest long enough. For example, when performing the bench press with the goal of growing your chest, your triceps are a synergistic muscle that are also taxed pretty heavily. If your rest periods are so short that your triceps give out before your chest nears failure on your next set, then you're not resting long enough to get an adequate chest stimulus. Even if your chest may be fully recovered by 2 minutes, perhaps your triceps need an additional 1-2 minutes to fully recover and not limit your next set.

Local muscle(s). Local muscle refers to the target muscle that you want to grow. For example, if you want to grow your biceps, you'll want the limiting factor in each exercise you do for your biceps to be the biceps themselves, nothing else. In this scenario, the only reason you stop a set should be because your biceps simply cannot perform another 3 (or less) reps.

Rest time checklist.

So rather than setting an arbitrary time limit on rest, you should rest long enough to check off each of the boxes below. If you can do that, then your rest periods are adequate to optimize hypertrophy. 

Rest time recommendations.

While I mentioned you shouldn't worry so much about putting a set time frame on rest periods, it's still helpful, for practical purposes, to get an idea of what rest periods may look like for your average lifter. If, after testing rest periods for yourself, you fall out of these ranges, then by all means, stick to what works for you.

Rest periods for compound movements are generally between 2-5 minutes. This is because it is much more likely that you will be limited by multiple limiting factors and not local muscle fatigue alone, since compound movements are taxing on the cardiovascular system and use multiple muscle groups. This is also the reason why shorter rest periods are more likely to hinder muscle growth - because more rest is required to recover all potential limiting factors.

For smaller isolation movements, you can usually get away with rest periods of 30 seconds to 1 minute. Usually after even this short a rest period, you can perform another 5 or more reps and bring the targeted muscle near failure. Isolation movements typically have minimal synergistic muscles and are not at all taxing on the cardiovascular system, so there is no need for extended rest periods.

Keep your rest times consistent.

It's a good idea to find a sweet spot when it comes to rest periods for each individual exercise. This will allow you to more easily track progress and determine whether you're actually getting stronger. When rest times are inconsistent, it becomes much more difficult to figure out what's causing changes in performance. Did you do more reps because your rest times were longer, or is it because you're getting stronger and building muscle? Did the weight feel extra heavy on your second and third sets because you're losing performance, or is it because you didn't rest long enough? This is why it's important to keep rest periods relatively consistent each time you perform a given exercise. Rest periods can and should vary from exercise to exercise, but should be kept consistent for each individual exercise. By doing this, you remove rest periods as a cause for changes in performance and can more easily track progress and apply progressive overload.

For example, say you find that the sweet spot for bicep curls is 45 seconds of rest between each set. This amount of rest allows your biceps to fully recover and perform at their best for each subsequent set without wasting time. You should then try your best to stick to 45 seconds of rest between each set of bicep curls while pushing to progressively overload by adding weight and/or reps over the long term. This allows you to have a more clear view of whether or not you're progressing properly. By varying rest periods from set to set you muddy the waters, making it difficult to determine why changes in performance occur.

Alternative time saving options

Many people will use shorter rest periods in order to get through a workout faster. But after reading this article, that may not sound like the best idea anymore, especially for compound movements. You may be wondering if there are any ways to get through a workout faster without reducing the overall stimulus of the workout. Luckily, there are. Better alternatives do exist, which either don't interfere with the hypertrophic response at all or do so very minimally. 

Super Sets

Supersets are when you perform one exercise immediately after another with no rest in between. This is best done with different muscles groups so there is minimal overlap with the muscles being used for each exercise. One example would be doing barbell curls immediately followed by tricep pushdowns. The barbell curls won't affect the tricep pushdowns. This will allow you to quickly finish one set of two different exercises, increasing time efficiency with minimal downside.

Giant Sets

Giant sets are very similar to super sets, except they involve more than two exercises. So you'll be performing three or more exercises in a row without rest in between each. Preferably this will also be with exercises that do not hit the same muscles. Giant sets should be reserved for times when it's really important that you get out of the gym faster, as they can lead to what we call "junk sets". Junk sets are sets that are not taken close enough to failure to produce an adequate training stimulus. This is common with giant sets because the first exercise or two that you perform can tire you out before you get to the last exercise, increasing the chance that you end a set prematurely due to fatigue.

Train Closer To Failure

The more volume you do, the more progress you can stimulate. However, let's not forget about another very important factor that can affect how strong of a stimulus you get from training: Intensity. The closer to failure you take a set, the stronger the training stimulus. When you're strapped for time and have to give up on finishing some of your sets, it may be a good idea to allow your RIR (Reps in Reserve) to decrease slightly and maybe even take a single set to failure to make up for the lack of volume. When volume is forced to decrease, you might as well increase intensity to compensate. 

Here's an example: If you were planning on doing 5 sets of bench press with an RIR of 3, but you end up having to cut your workout short and know you can only finish three sets, you could take those three sets a bit closer to failure and use an RIR of 2 or 1. You could also leave the first two sets at an RIR of 3 and take your last set to failure as well. There are many ways this can be applied to your benefit, just make sure not to over do it on the intensity and cause recovery problems.