Cluster sets, or rest-pause sets, are a great, but under-utilised tool in the gym. They have many uses, but the primary goal is to increase the effectiveness of a training session by either increasing the overall volume load, or increasing the average velocity of a specified movement within a training session.
What Are Cluster Sets?
Cluster sets utilise intra-set rest periods, of typically 10-15 seconds, to enable the athlete to either lift more weight per set, or produce more reps at a higher velocity per rep depending on the outcome goal of the session. An example would be a single set of 12 reps, split into mini sets of 4 reps. Between each mini set, you would rest 10-15 seconds, to allow a small period of recovery, before beginning the next mini set. After the 3 mini sets of 4 reps, you would rest a normal amount of time for strength training (about 2-3 mins in this example). This allows you to either lift a heavier weight within the set, or lift the weight with a higher average velocity of reps. Although the time taken for a set to be completed would be longer, it is absolutely worth it for the hybrid gains you can make, and especially useful for a general prep phase of a training programme.
What Are Some of The Benefits of Cluster Sets?
Heavier weight used per set.
Increased total training volume load per session.
Better maintenance of power output throughout a set.
Great for combining approaches of typically different phases of training.
Better rep quality.
Volume Load Example
Simply put, Volume Load is the number of reps multiplied by the number of sets, multiplied by the weight used (weight x sets x reps). VL is the primary principle behind progressive overload to increase muscle mass and/or strength. Regardless of sets and reps, the same muscular hypertrophy (increase in muscle mass) can be achieved whether you do 12 sets of 3, or 3 sets of 12. The main difference between the two, is that with 12 sets of 3 reps, you will gain more strength than with 3 sets of 12, simply because you can lift a heavier weight (1). Using this principle, cluster sets can be extremely useful! As an example, if an athlete is in a general preparation phase of training (usually at the beginning of a training cycle), the use of cluster sets would be to help the athlete gain a higher work capacity (typically the point of a general prep phase), while lifting a heavier weight than is typically possible with a normal high rep per set scheme. Therefore the athlete can gain muscle mass and strength endurance, while also gaining more overall strength.
If an athlete typically might be able to complete a set of 10-12 reps at approximately 65-70% of their 1 rep max using a traditional non-stop, single set approach, they might be able to go up to 5% heavier with the use of cluster sets. This is incredibly useful, as not only would they gain more muscle due to the higher volume load, they might gain strength quicker too.
Maintenance of Velocity
If the goal is power output, and the ability to produce repeated attempts of power output, cluster sets can be very useful for athletes. Cluster sets have been shown to maintain a higher velocity throughout a set compared to a traditional set approach. If you are an athlete, your ability to produce force exists with a time constraint, so you should be using cluster sets to maintain a higher overall set velocity!
An example would be an athlete doing squat jumps, typically, you might see a drop off of ~20% by the end of the set on, for example, the 6th and 7th rep. A lower velocity such as the aforementioned means the athlete is no longer producing enough FAST FORCE (high power output), so the athlete should end the set there. With a cluster set approach, an intra-set rest of 15s after 2 reps would allow the athlete to produce a higher average velocity per rep, allowing them to get more reps before seeing a significant reduction in velocity and terminating the set. In the example below, using PUSH technology to measure bar velocity, this athlete was able to maintain a bar velocity (trap bar jumps) of approximately 1.35m/s for 6 reps before dropping off, as opposed to the non-stop set, where the velocity dropped off consistently after only 4 reps.
"If you are an athlete, your ability to produce force exists with a time constraint, so you should be using cluster sets to maintain a higher overall set velocity!"
Cluster sets vs. traditional non-stop sets. Both sets were completed by the same athlete (on separate days) for 8 reps, with the same weight, with the cluster set utilising a 15s intra-set rest. Using cluster-sets, the athlete was able to get a higher total volume with a higher average velocity.
Programming Cluster Sets
Here is a simple step by step guide to implementing cluster sets into your programme:
Find the purpose for introducing cluster sets: velocity or strength/hypertrophy?
If it is training for repeated effort power or velocity, take a break of 10-15s after every 2nd or 3rd rep. Really, you should take an intra-set rest before the velocity drops off, but every 2-3 reps is a good start.
If training for strength and hypertrophy, take an intra-set rest of 10-15s after the rep quality starts to go down, or ideally a rep before that happens. As a guideline, feel free to refer to the adjusted 1RM percentage chart below. THIS DOES NOT APPLY to exercises such as power cleans etc, where the rep ranges according to 1RM are different. Also, you obviously wouldn’t be doing power cleans for hypertrophy (would you?)!
Clusters, depending on the type of cluster set you use, CAN BE DONE FOR ANY EXERCISE.
Approximate guidelines for adjusting 1RM% for cluster sets. These are just general recommendations, so individual 1RM percentages may differ.
Cluster sets are a great tool used by many coaches to help athletes get stronger and faster, but quite often they are forgotten in programmes. If you can utilise them properly, strength, power and muscle mass can all be increased more effectively and in a shorter time period. Get them in your programme today!
Train SMART, Train HARD, Be THE DIFFERENCE
References
Schoenfeld, B. J., Ratamess, N. A., Peterson, M. D., Contreras, B., Sonmez, G. T., & Alvar, B. A. (2014). Effects of Different Volume-equated Resistance Training Loading Strategies on Muscular Adaptations in Well-trained Men. Journal of Strength and Conditioning Research. 2909-18.
Tufano, J.J., Conlon, J.A., Nimphius, S., Brown, L.E., Seitz, L.B., Williamson, B.D., Haff, G.G. (2016). Maintenance of Velocity and Power With Cluster Sets During High-Volume Back Squats. International Journal of Sports Physiology and Performance. 885-892.