One of the most frustrating periods for a lifter is hitting a plateau.  You could be training diligently but suddenly you hit an invisible wall where the weights don’t budge anymore.  It’s during this time where lifters start seeking new training method or tools to blast out of this rut.  Fortunately there’s a solution, here’s how you can use cluster sets for rapid gains in power and strength.

What’s A Cluster Set?

A cluster set is a set with small intra-set rests (typically 10-30 second), that allow a lifter to perform more reps at a higher % of their 1, 3, 5, etc RM Max.  As an example, in a 5 rep cluster set a lifter can take an intra set rest after the second rep so that they do the 5 reps as a 2-2-1.  Because of the short rests between reps a lifter is able to lift a heavier load than what their normal 5 RM Max might be in a traditional set (5 straight reps).  There’s a lot of flexibility with the amount of total reps within the set, the % of load used, and the intra and inter set rest periods that allow a lifter to tailor the cluster sets for their specific goals.  This training method was first popularized by U.S Olympic Lifting coach Carl Miller and then saw a resurgence when accomplished strength coaches Christian Thibaudeau and Charles Poliquin advocated for the effectiveness of cluster sets with athletes.  A unique aspect of cluster sets is that this training method is validated in the gym by high level coaches and in science labs through various clinical trials.

Scientific Studies

A study 9 judokas comparing cluster training vs traditional training using their 4RM on parallel squats led researchers to observe that the cluster training group was able to lift a higher number of repetitions with a greater velocity. [1]

A different study also evaluated lifting velocity between traditional sets and cluster sets. Except this study divided the cluster sets into two types a cluster set of 2 (CS2) at 80% 1RM, a cluster sets of 4 (CS4) at 75% 1RM and a traditional set at 60% 1RM.  The groups all performed 3 sets of 12 on the back squat.  The researchers noted that the CS2 and CS4 groups both had greater peak velocity, mean velocity, peak power and mean power than the traditional set group.  And between the two cluster groups the CS2 group outperformed the CS4 group showing that increased frequency of intraset rest allowed for greater maintenance of power/velocity measurements during training.[2]

A study was conducted comparing traditional sets with cluster sets over the course of 12 weeks.  There were 22 subjects who had on average 6.5 years of training experience.  The groups were evaluated on their squat, bench, vertical jump and body composition over the course of the 12 week study.  The cluster training group had greater power output in the bench and vertical jump compared to the traditional training group and squat power in the cluster group was approaching significance.  The cluster training group also had greater strength gains in the bench and squat than the traditional group. There was no significant difference in lean mass between the two groups.[3]

Why Do Cluster Sets Work?

The short intra-set rest allows for partial replenishment of the ATP-CP stores, this is the energy system involved in explosive movements lasting a few seconds.  While complete replenishment of this system takes several minutes, the short rests in between reps allow for a partial replenishment so you can squeeze out a few more reps.  You accumulate less intra-set fatigue with clusters compared to traditional sets.  As an example with a traditional 5 rep set, fatigue will set in for most lifters in the final two reps which will impact the velocity they lift the weight.  With a cluster set because of the short rest, a lifter is able to better maintain velocity on the barbell for the entire 5 reps.  Because of this cluster sets outshine traditional sets because you can develop increased neuroefficiency.  A lifter will get better at recruiting high threshold motor fibers (fast twitch fibers) because they get more practice lifting at a higher load and barbell velocity %.  Finally,  cluster sets are a great way to refine technique.  Experienced lifters know that the set up for a lift can often make or break a lift  Because you re-rack or set the weights down during the intra-set rests in clusters, it gives you more opportunities to practice your set up on big lifts.  

Who Would Benefit From Cluster Sets?

Anyone stuck in a plateau should try cluster sets to bust through it.  This method of training is also something that athletes use throughout the year, especially combat sport athletes.  Cluster sets are effective ways of increasing absolute and relative strength without accumulating as much fatigue or putting on too much size.  Someone in a peaking phase of a program would benefit greatly from cluster sets.  Also, while cluster sets can be done for isolation exercises you’ll get the greatest bang for your buck doing them with compound exercises.

How To Use Cluster Sets For Strength: Typical cluster sets for strength will involve lifting taking intra-set rest in the 20-30 second range.

How To Use Cluster Sets For Power:  Cluster sets for power will also follow similar intra-set rest recommendations.  A unique thing about cluster sets for power is that you can break up the intra-rest set to ensure barbell velocity is at it’s peak throughout the set.  As an example a strength cluster for 5 reps could involve a 3-2 rep breakdown but a 5 rep power cluster set can be broken down as 2-2-1 to keep the barbell velocity as high as possible.  It’s important to note that too long of a rest between reps or too many reps in a cluster set can quickly turn this powerful method into inefficient singles or doubles.

Cluster Set +AMRAP

One method of peaking/autoregulation that I personally use with cluster sets is to do an AMRAP set for the final rep of a cluster set.  This is something I’ll typically do with a strength cluster.  Sticking with the 5 rep cluster set an example, I’ll do a few cluster sets with the 3-2 scheme and on my final cluster set I’ll do a 3-2+ set.  The goal is to at minimum do 2 reps on that final cluster set but I go for as many reps as I can.  This is a good way to gauge whether you can increase the weight on the barbell for your next cycle.

References

[1] Iglesias-Soler, E., Carballeira, E., Sánchez-Otero, T., Mayo, X., & Fernández-Del-Olmo, M. (2014). Performance of Maximum Number of Repetitions with Cluster-Set Configuration. International Journal of Sports Physiology and Performance, 9(4), 637-642. doi:10.1123/ijspp.2013-0246

[2] 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, 11(7), 885-892. doi:10.1123/ijspp.2015-0602

[3] Oliver, J. M., Jagim, A. R., Sanchez, A. C., Mardock, M. A., Kelly, K. A., Meredith, H. J., . . . Kreider, R. B. (2013). Greater Gains in Strength and Power With Intraset Rest Intervals in Hypertrophic Training. Journal of Strength and Conditioning Research, 27(11), 3116-3131. doi:10.1519/jsc.0b013e3182891672