Cluster Set Training: A complete guide

In a perfect world, we would train for as long as was required to achieve our goals in the gym.

In reality though, managing our training time effectively is one of the biggest challenges facing athletes, coaches, trainers and general gym goers.

The dilemma lies in making sure we rest enough between sets to maximise the quality of our strength and power output, but also packing enough work into your session to challenge our muscles, nervous system and make gains.

Enter the cluster set method. The perfect programming approach to pack more volume and work into the same amount of workout time — without gassing you out or compromising your strength, power or hypertrophy gains.

What are cluster sets?

Cluster sets flip the traditional resistance training set approach on its head. Instead of the classic 3 sets of 8 reps with 3 minutes rest (or its variations), programming with cluster sets take these longer sets and break them into sub-sets by adding a short intra-set rest period of “clusters”.

Cluster set examples

Lets take 3 traditional set-rep schemes for hypertrophy, strength and power training then and apply a cluster set programming structure to them.

3x10 - hypertrophy programming

• 3 sets of 10 reps with 120 seconds rest
• 3x3x3(15sec) with 1 min: 3 sets of 3 clusters each with 3 reps (15s rest between clusters)

4x6 - Strength programming

• 4x6 with 5mins: 5 sets of 5 reps with 5 minutes rest
• 4x3x2(20sec) with 2 mins: 4 sets of 3 clusters each with 2 reps (20s rest between clusters)

6x4 - Power programming

• 6x4 with 4mins: 6 sets of 4 reps with 4 minutes rest
• 6x4x1(10sec) with 1 mins: 6 sets of 4 clusters each with 1 reps (10s rest between clusters)
• 6x2x2(15sec) with 2 mins: 4 sets of 2 clusters each with 2 reps (15s rest between clusters)

For these examples, I aimed to keep the cluster sets as similar to the original programs. the total number of reps completed is very similar, as would the load on the bar be the same. The biggest difference you should notice is the change in rest times, something we will unpack shortly.

You don’t have to match cluster set volumes or program patterns this closely - there is lots of room for exploration of crazy and alternative programming structures should you want to — I have plenty of programming examples further on in the article!

Measuring cluster set performance with a barbell velocity tracker

The primary goal of clusters is to reduce total fatigue and increase the average bar speed across your workout (higher bar speed = greater force and power production). In order to know if this is occurring you should be tracking velocity for your cluster sets with the Metric VBT velocity based training app.

Download Metric VBT on iOS here →

Using the live feedback feature in Metric you can make your cluster sets responsive and dynamic, using a velocity target or velocity loss threshold to modify your cluster rep count, rest times, or training weight to further maximise your output and minimise fatigue accumulation.

I recommend using the Metric workout planner and pre-building all your clusters for the days workout, making it easy to simply start-stop each set of clusters with minimal fuss. The automatic rest timer in Metric will also give you accurate between-set rest periods so you know your training is hitting the ideal goal.

The difference between cluster sets, drop sets, supersets, and tri-sets

Before we get into benefits and science of cluster set training, it's important to clarify the differences between cluster sets, tri-sets, supersets and drop sets.

All the above are methods for maximising the efficiency and training density of your sessions without compromising the quality of your sets, it’s a bit simplistic, as there is plenty of variation within each method, but I find the below definitions helpful:

• Clusters are largely focused on enhancing the quality of your output  of each repetition (usually measured as bar speed or power output) while minimising the fatigue accumulation of the session (as measured by velocity loss).
• Drop sets are the opposite to cluster sets. Drop sets aim to increase the fatigue accumulation of an exercise by reducing load across a number of (usually) higher rep sets pushing you to higher and higher levels of exhaustion. This increases time under tension, metabolic stress and ideally hypertrophy.
• Supersets are simply ways of pairing exercises to better utilise rest periods. Take two complementary exercises and alternate between them, working one pattern or muscle group while the other is resting. This is a 5-star approach to training in the real-world and is something I program and do almost exclusively.
• Tri-sets Simply a superset but with three exercises in it.

Supersetting and Tri-setting does not have to be mutually exclusive from cluster sets. You can easily perform cluster sets on an exercise while also supersetting it with another movement, simply use the longer rest period taken between sets and perform another exercise for a more traditional set-rep protocol. For example; perform a 3x3 cluster of hang power cleans, then during the 90 seconds rest between sets, go and perform a set of 8 reps on the seated row.

Cluster set benefits

Cluster sets offer several advantages for those looking to enhance their training efficiency

Less fatigue accumulation, higher bar speed

Cluster sets help in managing cumulative fatigue during workouts. By allowing short rest intervals within sets, they enable athletes to partially recover, thereby reducing muscle fatigue. This approach can lead to better performance in subsequent sets and exercises, as the athlete experiences less overall fatigue. It's particularly beneficial in high-volume or high-intensity training phases, where managing fatigue is crucial for sustained performance and reducing the risk of overtraining.

In a study by Tufano et al. in 2016, two cluster protocols were compared with a conventional 3x8 session. The study showed that cluster methods maintained higher velocities across the same training load and rep number compared with the standard protocol. As a result the lifters experienced lower acute fatigue and generated more total power and force during their training session.

Greater power output and adaptations

Cluster sets enable athletes to maintain a higher average bar speed throughout their repetitions due to lower fatigue accumulation and therefore greater intent when lifting. This is particularly beneficial for power development and neuromuscular efficiency. By breaking down a set into smaller clusters with brief rest periods, the athlete can focus on explosive movements for each rep, reducing the likelihood of speed decrement that often occurs in traditional sets, taking advantage of the Henneman size principle of activating our largest most powerful motor units.. This approach is especially advantageous for sports where power output is crucial, allowing athletes to train more effectively within their specific performance parameters.

In the 2018 study by Morales-Artacho, two groups completed a foundational 8 week training block of hypertrophy and strength training before being split into different programs for a 3-week power peaking phase; one group did traditional sets (6x6) and the other clusters with 30-seconds rest (6 sets of 3x2 clusters) for a loaded jump training block.

After the power phase, the cluster group showed significantly greater improvements inpower output across 25%, 50% and 75% loads compared to the group that did straight sets.

The results for strength adaptations were flat-ish, with the traditional sets seeing slightly better results in week 11 testing. However, given the program was focused on power in the peaking phase, and the final training phase used only 20% of BW in the training sets, this strength effect results is not very relevant - a curious finding would have been to do a 3-week strength peaking phase comparing clusters and traditional sets.

Time efficient training

Cluster sets are an efficient way to condense workout sessions without sacrificing the volume of work. By incorporating short rests within sets, athletes can maintain higher intensity and quality of work. This structure allows for completing the same volume of exercise in a shorter timeframe, making workouts more time-efficient. This is particularly useful for athletes with limited training time who need to maximize their workout efficiency.

The unique format of cluster sets reduces the total resting time needed during workouts. By interspersing brief rest periods within sets, athletes can recover quickly, maintaining a higher overall workout intensity. This reduction in downtime not only makes workouts more time-efficient but also keeps the heart rate elevated, potentially enhancing cardiovascular benefits and caloric expenditure.

Faster recovery after training

Athletes using cluster sets often report faster recovery post-training. The shorter, more intense bursts of activity with brief recovery periods can lead to less muscle damage and metabolic stress compared to traditional sets. This can result in a quicker return to baseline physiological states, allowing for more frequent training sessions or higher quality subsequent workouts. This benefit is particularly valuable for athletes undergoing multiple training sessions per week, those in a high-frequency training phase, or when going through a rebuild phase after injury or time away from training.

Training recommendations for cluster sets

Ultimately, clusters are a method aimed at maximising bar speed, minimising fatigue accumulation, and increasing the quality of your reps in a time efficient way. This has most commonly been a way to benefit power training, but with some small tweaks, the same cluster set approach can also be incredibly effective for developing strength and hypertrophy.

Cluster set training for power

For power, the benefits and time-efficiency of clusters is a high-performing approach to training. Clusters are a top of the pile, use-very-often category of tactic, use them frequently and be comfortable having a large portion of your power prescriptions involving clusters.

Coming soon: Clusters for power training program and specific guidelines →

Cluster set training for strength

For strength training, clusters have some benefits, and possibly some drawbacks.

While faster bar speed and minimising fatigue accumulation in sessions can be beneficial for making strength gains, strength training also requires at least some work to be a grind - pushing sets closer to the point of failure and with loads closer to 1RM to develop the skill of maximum strength expression.

For strength development I consider clusters a sometimes tool. Use them on occasion or for only certain exercises as a way to mix up training, accumulate more volume, reduce the fatigue effects of training (in-season or to deload), or as a way to practice the skill of short sets (a perfect application in powerlifting where the sport requires not just lifting weight but racking, unracking etc - something that can be practices well with clusters).

Cluster set training for hypertrophy

Cluster sets can be effectively integrated into hypertrophy training, offering a unique approach to muscle growth.

By allowing for heavier loads and higher-quality repetitions, cluster sets enable you to maintain mechanical tension on the muscles, a critical factor for hypertrophy, especially for the type II, larger motor units.

Cluster sets for hypertrophy are unique in their application, as you should still be aiming to match volume and tonnage of traditional sets and keep the rest periods short. Because clusters are a training strategy for reducing metabolic stress, using clusters exclusively is probably a sub-optimal approach is hypertrophy and muscle growth is your #1 training goal, a potential high-yielding approach would be to use cluster sets on your primary compound lift to get a blend of strength and hypertrophy stimulus, then switching to traditional sets, or drop set approaches for your isolation and accessory lifts.

Even with cluster sets, it's crucial to keep an eye on the total training volume and intensity. Adhering to guidelines like Dan John's Rule of ten for strength clusters or applying a tight velocity loss threshold for power training can be useful. For hypertrophy training, keeping consistent on total training tonnage and work for each exercise should be your goal, aiming for a gradual single-digit percentage increase in tonnage each week, and ensuring you are still recovering from this and gaining muscle/weight at the rate you need.

Cluster set programs

There are a number of factors to consider when incorporating cluster sets into your training plan.

How to write clusters into your program (nomenclature)

Because clusters introduce another sub-set to the structure they require a unique naming convention.I like to use the following approach to doing this:3x (4x 2) 30/120 rest.

This represents three sets, each comprising four clusters, with two reps per cluster. There's a 30-second rest between clusters and a 120-second rest between sets.

Custer set logistics

Consider racking and walkout time

Certain exercises, like deadlifts, barbell rows and jumps, are highly conducive to cluster training. Others, like back squats, may pose challenges due to more involved unrack - rerack process. It's important to consider this setup and dismount time into your cluster design, as it can consume rest time and sap more energy than you think, especially on loads above 90%.

6x 2 clusters might be easy and fun on a trap bar deadlift, but for back squats, going with 4x 3 clusters is probably more appropriate; this would be 33% less walkouts required for the same number of reps.

Do the maths on total cluster duration

It’s also a good idea to do the maths on how long a cluster protocol is actually going to take, it might seem shorter on paper, but 10x 2 with 60 seconds will still be 10 minutes of rest, maybe 5x2 with 60seconds will be the better approach? Be sure to practice your new clusters with some easy sets or map them out on paper to see how the session will actually play out. Refer to the chart used earlier in this blog post showing the time cost and spacing of different cluster set protocols.

Before starting a cluster set workout, make sure the training space is well-organised.

Equipment like stopwatches, your phone is well positioned with Metric framed correctly and your sets pre-loaded into the workout so you can easily start and stop each cluster easily.

Download Metric VBT on iOS here →

It often helps to have a training partner or coach help with starting and stopping your rest timer as well as run your phone for velocity tracking. In Metric VBT you can continuously record for an entire set of clusters with rests up to 30 seconds, or if you prefer stop and start the recording for each cluster separately.

Exploring cluster set protocols further

There are numerous ways to craft cluster set routines, with creativity being the only true limit, so get creative and explore the freedom of unique and different set-rep-cluster-rest combinations to see what fits your training environment! And as always, just like with all intelligent program design, account for total session duration, progressive overload, fatigue monitoring and training goals before seeing if clusters are a good fit for you.