When it comes to improving power, strength, and size, there are multiple workout variables to take into account. Possibly the biggest variable when aiming to accomplish either or all of the goals is continual progressive overload. This is the art of applying a calculated progressive stimulus on the body while simultaneously avoiding burn out.
It’s a no brainer, but an increase in volume at a certain intensity is one of the best ways to track improvements in the gym. One way to increase your total load in workouts is with cluster sets/training. Cluster sets are smaller sets built-in a larger set with rest increments that typically range from 10-30 seconds.
Most often, cluster training is used to increase how much an athlete can perform at certain intensities, as traditional sets can be limiting to one’s work capacity.
What Does Cluster Training Look Like?
Cluster sets can take different forms and there isn’t a one-size-fits-all cluster set structure. If you search around the internet and read other coach’s interpretations, then you’ll notice all of their methods vary slightly, but all aim to accomplish the same thing. This is due to everyone viewing and aiming to accomplish strength, power, hypertrophy, and endurance through slightly different means.
You can program cluster sets for any of the four training adaptations listed above, and most often you’ll see them used for compound movements. At times, you may see them used for accessories, but that’s a little more rare, and they’re often used on the more demanding accessories that follow compounds.
Before looking at the cluster set examples below, it’s important to gain an understanding of variables that make up a cluster set. To read more about cluster sets, all of the current research on them, and how they’ve been used in studies before, then I’d recommend checking out this 2017 review.
There are four variables you should acknowledge before beginning to program clusters.
Inter-Set Rest Intervals
I mentioned it above, but the normal inter-set rest interval for cluster sets range from 10-30 seconds. These intervals will vary depending on your goals, intensity, and total work. If that’s confusing, then I listed out a few scenarios with potential inter-set rest guidelines below.
- Power: 15-30 second rest intervals
- Strength: 10-30 second rest intervals
- Hypertrophy: 10-20 second rest intervals
What’s most important when figuring out rest for your cluster sets is gauging your capabilities for moving weight efficiently and safely. For example, if you’re missing reps due to the limited rest, then scale back the weight, or slightly increase your rest interval.
Total Reps Per Set
The next variable we’ll look at is the total reps you plan to perform for each cluster set. This is where cluster sets look similar to what you probably already know about traditional reps for training adaptations. The only real difference is how you plan to break up the smaller sub-sets within the total reps. Check out the examples below.
- Power: 4-5 total reps, so a cluster could look like: 2-2-1 or 2-1-1
- Strength: 5-7 reps, so a cluster could look like: 2-2-1 or 3-2-2
- Hypertrophy: 8-10 reps, so a cluster could look like: 3-3-2 or 4-3-3
As you can see, the smaller subsets are all similar (1-4 reps), but they equate to a larger set, which correlates with a traditional set’s goals. Yes, in this scenario, power is a little bit extrapolated compared to traditional sets due to the smaller subsets.
The next variable to consider is total rest taken between cluster sets. One of the main focuses of cluster sets is accomplishing a certain amount of work in different time allotments. This being said, your rest in-between sets can be paramount to successfully using these, as too little will equate to fatigue accumulation, form breakdown, and failed reps.
- Power: 2-3 minutes
- Strength: 1-3 minutes
- Hypertrophy: 1-1:30 minutes
Rest in-between sets will be similar to what traditional sets look like. Ideally, take the rest you need to get in the work without missing reps, or having to drop intensities.
The final variable for programming successful cluster sets is choosing an intensity. This is the variable where coaches and athletes will most likely have the most variability. When working at higher intensities, it’s going to be tough to accurately provide you with perfect numbers below, as everyone’s workload typically varies most at higher percentages.
- Power: 8-9 RPE or 90%+ 1-RM
- Strength: 7-8 RPE or 75-85% 1-RM
- Hypertrophy: 6-8 RPE or 70-80% 1-RM
These numbers will vary depending on your training goal and capabilities, so please, take these as general guidelines, not an end-all-be-all solution.
Examples of Cluster Sets
Below, I’ve included three examples of what cluster sets/training could look like when training for power, strength, and hypertrophy.
- 3 x 5 (2-2-1) – 15 second rest in-between each subset, 90% 1-RM intensity, and 3-minutes total rest between sets.
- 2 x 4 (2-1-1) – 20 second rest in-between each subset, 93% 1-RM intensity, and 4 minutes total rest between sets.
- 4 x 6 (2-2-2), 15 second rest in-between each subset, 85% 1-RM intensity, and 3-minutes total rest between sets.
- 3 x 8 (3-3-2), 10 second rest in-between each subset, 80% 1-RM intensity, and 2.5 minutes total rest between sets.
- 4 x 8 (3-3-2), 10 second rest in-between each subset, 77% 1-RM intensity, 2-minutes total rest between sets.
- 3 x 10 (4-3-3), 5 second rest in-between each subset, 75% 1-RM intensity, 2-minutes total rest between sets.
Benefits of Cluster Sets
There are a few benefits that come along with utilizing cluster sets and these benefits will vary slightly depending on your goal and usage of them. Below I’ve listen three potential benefits to programming cluster sets in your training.
1. Increased Total Volume: We discussed it above, but working with higher intensities can create a limitation when aiming to hit higher reps. Cluster sets work to displace work over smaller sets, which can allow an athlete to hit more reps. This 2015 study demonstrated that cluster training compared to traditional sets promoted great total work volume and higher average power.
2. Potential Plateau Breaker: If you’re stuck at a certain weight for a dictated amount of reps, then cluster sets could be a potential way to possibly break through a plateau. Their sole purpose is to allow for a potentially higher training volume, so it could help you push past a plateau.
3. May Help Increase Strength: A 2013 study compared subjects who followed traditional sets (4 x 10) and intra-rest interval sets (8 x 5) over the course of 12-weeks. Authors found that both groups increased their strength in the tested lifts and saw a shift in muscle fibers, but the intra-rest set group saw slightly greater increases in strength. Although, researchers note that this could be due to the groups shifting their 1-RMs every 4-weeks, thus allowing the 5-rep group to increase quicker, as it’s less reps per set.
Cluster sets can be a useful tool for increasing one’s total work and volume during a workout. They allow for the potential to perform more reps with certain percentages while attempting to avoid form breakdown. Is there a one-size-fits-all cluster set format? Not necessarily, although, the variables that make up cluster sets should be kept consistent to avoid misuse of their meaning/structure.
Feature image from @canadianprotein Instagram page.