Can Cluster Sets Help You Gain Muscle and Strength? What Science Says

Building muscle when you’re new to weightlifting is mostly a game of patience and persistence.

As long as you show up, finish your workouts, and follow a sensible diet plan, you’ll gain muscle and strength like clockwork.

After your “newbie gains” dry up, though, progress comes in fits and starts.

And it’s at this stage that many people cast their gaze about for more “advanced” training techniques, hacks, and shortcuts.

Things like supersets, rest-pause sets, German Volume Training, and so forth.

Another technique you may have heard of is known as doing cluster sets, which boils down to taking short breaks during your sets, but resting less between each set.

Some people say this method triggers muscle growth above and beyond what you could achieve with traditional weightlifting, while others say it’s a pointless gimmick.

Who’s right?

Can cluster sets help you gain muscle and strength?

And if so, are they better than more traditional training styles?

You’re going to learn the answers to these questions and more in this article.

By the end, you’ll know exactly what cluster sets are, how they’re supposed to increase muscle growth, whether or not they’re effective, and how to include them in your training if you choose to do so.

Let’s start at square one.

Table of Contents

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• What Are Cluster Sets? 
• Why Do People Do Cluster Sets?
• Can Cluster Sets Help You Build Muscle?
• Can Cluster Sets Help You Get Stronger?
• How to Use Cluster Sets in Your Training
• The Bottom Line on Cluster Sets

What Are Cluster Sets? 

First, some clarifications on the lingo.

A “set” is a fixed number of repetitions of a particular exercise.

For instance, if you do 12 reps of biceps curls and stop, you’ve done one set (of 12 reps). Then, you’ll usually rest two to three minutes before doing another set.

If you were to do three sets, here’s what this would look like if you wrote down each rep of each set in your workout journal:

Set 1

Reps: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Rest: 2 minutes

Set 2

Reps: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Rest: 2 minutes

Set 3

Reps: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12

Rest: 2 minutes

That’s how a traditional set works.

In a cluster set, you break up a regular set into a cluster of mini-sets (hence the name) with a short break in between each. Then, you take a shorter break than normal between your cluster sets.

For example, instead of doing 12 reps of biceps curls in each set and then resting, you might do four mini-sets of three reps each, with 20 seconds rest between each mini-set.

Read: How Long Should You Rest Between Sets to Gain Muscle and Strength?

Here’s how this would look if you wrote it all down:

Cluster Set 1

Reps 1, 2, 3 (1st mini-set)

Rest 20 seconds

Reps 4, 5, 6 (2nd mini-set)

Rest 20 seconds

Reps 7, 8, 9 (3rd mini-set)

Rest 20 seconds

Reps 10, 11, 12 (4th mini-set)

Rest 1 minute

Then, you’d repeat this pattern for the rest of your remaining sets of biceps curls (or whatever exercise you’re doing).

During the rest periods between each mini-set, you generally want to re-rack the weight or put it down.

For instance, if you were doing bench press cluster sets, you might do three or four reps, re-rack the weight, rest 20 seconds, un-rack the weight, do another three or four reps, and repeat until you get 10 or 12 reps. Then you’d rest for another minute or two, do another cluster set, and continue until you’ve finished all of your sets for that exercise.

You can program cluster sets in a variety of ways, but generally, each cluster set includes somewhere around 10 to 20 total reps, 2 to 6 reps per mini set, 20 to 30 seconds rest between each mini-set, and 1 to 2 minutes rest between cluster sets.

Cluster sets are close cousins to rest-pause sets, which involve more or less the same strategy with a slight twist.

Read: How to Use Rest-Pause Training to Gain Muscle Faster

With rest-pause sets, you take a set to muscular failure (or just short of it), rest for a moment (usually 20 to 30 seconds), do another set to near-failure, followed by a short rest and another set, and so on, until you reach a predetermined number of total sets or you fail to get a certain number of reps per set.

Basically, a rest-pause set is like a less structured kind of cluster set, and both kinds of training will produce similar results in terms of strength and muscle gain.

Summary: A cluster set involves breaking up a traditional set into a “cluster” of mini-sets of around 2 to 6 reps each with 20 to 30 seconds rest between each mini-set, and 1 to 2 minutes rest between each cluster set.

Why Do People Do Cluster Sets?

The main reason people like cluster sets is due to a phenomenon you’ve likely experienced yourself:

Toward the end of a traditional set, your last few reps probably slow down considerably. If you’re training close to failure, your technique may also begin to deteriorate.

By interspersing more rest throughout your sets, you can reduce fatigue throughout the set, which allows you to . . .

• Lift the same weight for more total reps per set, or . . .
• Lift the same weight for the same number of reps, but complete each rep faster, or . . .
• Lift the same weight for the same number of reps, but complete each rep with better technique.

In other words, the rationale for cluster sets is to reduce fatigue throughout your workout so you can accomplish your reps with better technique and more vigor.

And if you can do more weight or reps in your workout with good technique, you’ll gain more muscle and strength over time.

People generally use cluster sets for their compound exercises like the squat, bench and military press, and deadlift, but you can also use them for isolation exercises like curls, side raises, calf raises, and so forth.

Summary: Weightlifters use cluster sets to reduce fatigue during their workouts, with the goal of increasing the number of reps they can do with a given weight and performing their reps more explosively and with better technique.

Can Cluster Sets Help You Build Muscle?

Some people claim cluster sets are an effective strategy for building muscle, in the same vein as rest-pause sets or blood-flow restriction training.

The main benefit of cluster sets, they claim, is that they help you do more total reps in your workouts.

And this is mostly true.

Assuming you’re lifting with sufficiently heavy weights (60 to 80% of your 1RM) and trying to add weight to your lifts over time, an effective way to further increase muscle growth is to simply do more reps.

Think of it this way:

The biggest driver of muscle growth is progressive tension overload—forcing your muscles to produce more tension over time—and this is best accomplished by lifting heavy weights close to the point of technical failure.

Read: The Best Way to Stimulate Muscle Hypertrophy (Build Muscle)

If you do more reps with the same weight, you’re forcing your muscles to produce slightly more tension in each set, which should lead to slightly more muscle growth.

The same thing is true of doing more sets.

Up to a point, the more hard sets you do (sets taken close to the point of absolute failure), the more muscle you’ll build.

Thus, anything that helps you do more reps and sets—like cluster sets—will probably help you build more muscle.

And that’s what some research shows.

Several studies have shown that cluster sets can help weightlifters do more total reps, complete their reps with greater vigor, and even gain slightly more muscle and strength than traditional sets.

Now, at this point you may be wondering, would doing more regular sets have the same benefits as cluster sets?

That is, if you do 4 sets of 9 reps of regular sets (36 total reps), would you get similar benefits to 3 sets of 12 reps of cluster sets (36 reps)?

Probably.

To my knowledge, no studies have directly compared the muscle-building effects of doing regular or cluster sets for the same total number of reps, but based on what we know about muscle growth, it’s fair to assume the results would be similar.

So, why bother with cluster sets at all then?

Well, you don’t have to, but one area where cluster sets shine is breaking through plateaus on certain exercises, especially isolation exercises.

For example, let’s say your workout calls for 3 sets of 8 to 10 reps of dumbbell side raises with 30 pounds. You’re using double progression to increase your weights, and so before moving up to 35 pounds, you want to get 10 reps on all three sets.

Read: 8 Highly Effective Ways to Get Stronger on Your Isolation Exercises

For the past few weeks, though, you’ve only been able to get 8 or 9 reps on your sets. After 5 or 6 reps, your shoulders start to burn, and you barely manage to squeeze out a few more before your form falls apart.

By using cluster sets, though, you may be able to get one or two more reps on each set, thus allowing you to hit your rep target and move up in weight.

Of course, this won’t work forever (you can’t just keep adding more and more rest between reps), but it’s a handy stopgap for when you’re stuck.

Summary: Cluster sets aren’t any better or worse than regular sets for building muscle, but they take considerably more time to complete. That said, they can be helpful for breaking through weightlifting plateaus, particularly on isolation exercises.

Can Cluster Sets Help You Get Stronger?

Getting stronger mostly boils down to two things:

1. Learning and practicing proper technique on the compound exercises like the squat, bench and military press, and deadlift.
2. Building muscle.

Do those two things (and don’t get injured), and you’ll get stronger year after year.

You’ve already learned about how cluster sets affect muscle growth, but some people also say cluster sets help with learning and practicing proper technique.

How?

When it comes to heavy weightlifting, proper technique doesn’t just refer to how you move your body when doing an exercise. It also refers to how forcefully you can contract your muscles when throwing around heavy weights.

For example, there are many people who have picture-perfect squat technique when using high reps and low weight, but their technique falters when they try to do a one-rep max because they don’t practice squatting heavy weights.

Read: How to Squat: The Definitive Guide (Plus 12 Proven Ways to Improve Your Squat!)

Even people who do practice with heavy weights often find their technique starts to skid after a few sets, diminishing the quality of their reps.

This is where cluster sets enter the picture.

In theory, cluster sets should allow you to do more heavy sets in a workout with good form than you’d be able to otherwise.

There isn’t much research on this strategy, but one study conducted by scientists at Charles University offers some insight into how this might work.

The researchers had nine 23-year old men with at least 18 months of weightlifting experience do two workouts:

1. In workout one, the men performed six sets of squats for as many reps as possible.
2. In workout two, the men performed as many cluster sets of squats as possible.

Before doing the workouts, the researchers helped each weightlifter find a weight that would allow them to reach peak power output for a single rep.

Now, power isn’t the same as strength, and the weights these people were using were significantly lower than what you’d generally use on a strength training program, but it’s reasonable to assume that workouts that improve power will also improve strength to a certain degree.

Next, the researchers had the weightlifters complete both workouts. Everyone finished their sets—whether they were doing traditional sets or cluster sets—when their power output fell below 90% of their max power for two consecutive reps (when their reps started to get slow and sloppy, basically).

To minimize the chances of fatigue from one workout interfering with performance on the other, the researchers split the weightlifters into two groups, with one group doing Workout One first and the second group doing Workout Two first.

In both cases, everyone performed the workouts three days apart.

The key finding was that the weightlifters were able to get 4 to 6 reps in each cluster set on average, versus just 3 to 4 reps per traditional set.

Remember, all of these reps were fast, snappy, smooth reps—the kind you experience during the first one or two reps of a set.

That means the cluster set group was able to get in about 25% more quality repetitions than the traditional set group, which could lead to greater strength gains over weeks, months, and years.

There’s more to the story, though.

First of all, the weightlifters took considerably more time to finish their workouts when they were using cluster sets. On average, it took them almost 4 minutes to finish each cluster set, whereas it only took them around 25 seconds to finish each traditional set.

They did 6 sets of squats in their workouts, so it took around 24 minutes to finish their cluster set workouts, but only 15 minutes to finish their traditional set workouts.

Not a huge difference, but that would add up over weeks and months of training, especially if they were doing cluster sets on multiple exercises.

This makes you wonder . . . if it took these weightlifters almost twice as long to finish their workouts using cluster sets than traditional sets . . . and they only did 25% more quality reps using cluster sets than traditional sets . . . couldn’t they have gotten similar results by just doing more traditional sets?

Yes.

You see, it’s true that doing cluster sets helps you do more high-quality reps in a single set, but that’s simply because you’re resting during the set. If you look at how many total reps you can do over a period of time, you can do about the same number of reps with traditional sets as you can with cluster sets.

For example, had the weightlifters in this study been given 24 minutes to do their traditional sets, they could have completed 9 sets instead of 6—which would have meant they did slightly more total reps than when they used cluster sets.

In the final analysis, then, cluster sets are probably equally effective as traditional sets for gaining strength. They allow you to get slightly more reps per set, but each of these sets takes longer, too, so it’s probably a wash in the end.

So, if cluster sets don’t offer any real advantages over traditional sets, why would you ever want to do them?

Boredom is one reason.

If traditional sets are getting stale, cluster sets might inject a little more fun into your workouts. There’s much to be said for any training technique that gets you excited about working out.

In other words, when it comes to getting stronger, you can look at cluster sets as a benign novelty. They aren’t any better or worse than traditional sets, but they might be more enjoyable.

Summary: Cluster sets allow you to do more high-quality reps in each set than traditional sets, which would likely improve your strength over time, but they also take considerably longer than traditional sets to complete. Thus, both styles of training are probably equally effective for improving strength.

How to Use Cluster Sets in Your Training

First and foremost, you should never look at cluster sets as the killer app of your workout routine.

Instead, they’re best viewed as a potentially helpful tool for achieving progressive overload, and only then if you’re already following a well-designed strength training program.

So, how and when should you include cluster sets in your training?

As I mentioned earlier in this article, I think cluster sets are most helpful when trying to break through weightlifting plateaus, which I define as failing to add weight or reps to a particular exercise in at least two weeks.

Read: 6 Proven Ways to Break Through Weightlifting Plateaus

Many people recommend you use cluster sets for your compound exercises like the squat, bench and military press, and deadlift, but I like to use them for my isolation exercises, and I recommend you do the same.

Why?

Well, cluster sets are most helpful for breaking up traditional, high-rep sets, and I tend to favor lower reps (6 to 8 or less) for compound exercises, for reasons Mike discusses in this podcast:

Listen: Research Review: What’s the Best Rep Range for Building Muscle?

There are also practical issues with using cluster sets for compound exercises.

For example, continually un-racking and re-racking a barbell while bench pressing, military pressing, or squatting can be very frustrating and fatiguing. While this isn’t an issue with deadlifts (you can just rest the weight on the ground), most people don’t enjoy doing high-rep sets of deadlifts, so it’s a bit of a moot point.

So, what exercises can cluster sets work well for?

Pretty much all isolation exercises, as well as some compound exercises that allow you to easily rest between each mini-set.

For example, cluster sets can work well when used with these isolation exercises:

• Dumbbell side lateral raise
• Dumbbell rear lateral raise
• Face pull
• Dumbbell bicep curl
• Barbell bicep curl
• Cable tricep extension
• Cable fly
• Standing triceps pushdown
• Standing lat pushdown
• Leg extension
• Leg curl
• Standing or seated calf raise

And they can also work well with these compound exercises:

• Pull-up
• Chin-up
• One-arm dumbbell row
• Barbell row
• Lat pulldown
• Dip
• Leg press
• Hack squat
• Hip thrust

You have many different options in terms of how you implement cluster sets.

As you’ll recall from earlier in this article, a cluster set typically involves breaking up a traditional set into several mini-sets of around 2 to 6 reps each with 20 to 30 seconds rest between each mini-set, and 1 to 2 minutes rest between each cluster set.

I encourage you to play around with variations on that basic template. You may find that you like to do 2 or 3 mini sets of three or 4 reps each, for example, or that you prefer 3 or 4 mini-sets of 2 to 3 reps each, or some other combo.

Here are a few more examples of how you could implement cluster sets in your workouts:

Cluster Set Example 1

Reps 1, 2

Rest 15 seconds

Reps 3, 4

Rest 15 seconds

Reps 5, 6

Rest 15 seconds

Reps 7, 8

Rest 15 seconds

Reps 9, 10

Rest 1 minute

Cluster Set Example 2

Reps 1, 2, 3

Rest 20 seconds

Reps 4, 5, 6

Rest 20 seconds

Reps 7, 8, 9

Rest 20 seconds

Reps 10, 11, 12

Rest 1 minute

Cluster Set Example 3

Reps 1, 2, 3, 4

Rest 30 seconds

Reps 5, 6, 7, 8

Rest 30 seconds

Reps 9, 10, 11, 12

Rest 1 minute

Summary: Cluster sets are best used as tools for breaking through weightlifting plateaus on isolation exercises and several compound exercises such as the pull-up, chin-up, barbell row, one-arm dumbbell row, and leg press.

The Bottom Line on Cluster Sets

Despite what you may have read elsewhere, cluster sets aren’t a “hack” or “shortcut” for building muscle.

Instead of looking at them as a standalone training strategy, they’re best viewed as a training tool that can be helpful in certain circumstances.

Typically, a cluster set involves breaking up a traditional set into a “cluster” of mini-sets of around 2 to 6 reps each with 20 to 30 seconds rest between each mini-set, and 1 to 2 minutes rest between each cluster set.

Most weightlifters use cluster sets to reduce fatigue during their workouts, with the goal of increasing the number of reps they can do with a given weight and performing their reps more explosively and with better technique.

In reality, though, research shows cluster sets aren’t any better or worse than traditional sets for gaining muscle or strength. You can do more total reps in a cluster set than you can with a traditional set, but each cluster set also takes much longer to complete.

Thus, in most cases, you can get similar results by simply doing more traditional sets.

That said, cluster sets can be particularly helpful for breaking through weightlifting plateaus, especially on isolation exercises like side raises, dumbbell curls, and so forth.

All in all, that’s my favorite way to use cluster sets: as a tool for breaking through weightlifting plateaus on a few exercises.

If you want to learn more about “advanced” strategies for gaining muscle and strength, you want to check out these articles:

⇨ Should You Use Supersets to Build Muscle Faster? What 18 Studies Say

⇨ Does Blood Flow Restriction (Occlusion) Training Really Work?

⇨ How to Use Rest-Pause Training to Gain Muscle Faster

⇨ Can Hyperventilating Make You Stronger? What Science Says

⇨ The Definitive Guide to Full-Body Workout Routines

What’s your take on cluster sets? Have anything else to share? Let me know in the comments below!