What Are Cluster Sets and Can They Improve Muscle Growth?

Cluster sets for muscle growth

The new review outlines how cluster sets fit into your everyday workout routine.

Take a look at the below or click here:

Traditional sets are simply 12 reps straight, drop sets are doing 12 reps, then reducing the load, doing more reps, and reducing the load again. The rest-pause involves doing 12 reps, resting, then doing 4 reps.

Then we get to our star of the show: the cluster sets. 

As you can see, they involve doing 4 reps, resting, then doing another 4 reps, resting, and then another 4 reps.

That's how a cluster set makes up 12 reps, as opposed to our "traditional" sets of just doing 12 reps in succession.

But how long should we rest in between our cluster sets?

The review outlined how three different rest periods were analysed in a previous study:

Group number 1, the 3 rep max with 20 seconds of rest, got the best muscle growth results.

A previous study also found that rest periods of 15-30 seconds between cluster sets "might be better from a hypertrophy point of view."

The authors also point to a very recent study that found creatine monohydrate to notably increase the fat-free mass and strength levels during cluster sets! So make sure you’re taking some creatine when you’re doing cluster sets! 

Cluster sets are so favourable because you're working at such high intensity during every rep.

Research shows they lead to lesser velocity loss, higher force and more volume compared to traditional sets.

The authors suggest this might be because of mechanical tension, which is one of the three principles of muscle growth (as I outlined in this article).

And in this squatting study, subjects either did:

Traditional sets: (4 rep max load) 3 sets of reps to failure, with 3 minutes rest in between.

Cluster sets: 36 seconds of rest between each rep.

So what did they find?

The cluster set group was able to pump out more reps! This meant they achieved more volume.

Also, mechanical performance was generated, showing a potential benefit to generating better muscle growth. 

As researchers put it in the review:

"Cluster sets takes advantage of the fast phosphocreatine recovery kinetics and allows either a higher mechanical output within the same training volume or a higher volume at the same mechanical output."

So what are some other ways we can use cluster sets?

This is what the researchers recommend click here:

You can see how rest periods and reps performed in between can vary. So pull this image up next time you're in the gym and want a new challenge!

The authors add these practical applications for us:

The bottom line on cluster sets

Is that cluster sets are a great way to induce potentially more muscle growth via mechanical tension, one of the three principles of muscle growth. Cluster sets also allow for more volume to be completed. You can complete a cluster set by doing 3-5 reps, then resting 10-20 seconds for the upper body, or 15-30 seconds for the lower body, before performing your reps again. Complete this between 3-4 blocks. Adding creatine monohydrate might be beneficial on the days you're performing this. You can also incorporate drop sets within-cluster sets. All of this helps to overload the muscles in a way they might not be used to, which could translate into more muscle growth.