Article written by Joshua Elliott
Cluster sets, in the scientific literature, are defined as “Inter-Repetition Rest.” Utilizing cluster sets is simply taking an extra 15-30 second rest in the middle of a given set of reps. The benefits of cluster sets include:
Increasing Peak Power Output
Allows you to train at heavier loads longer
Limits Metabolic Stress and Fatigue when compared to straight sets
Has positive long-term effects on strength performance
Allows you to maintain bar speed and technique
Increase Type IIa Muscle Fiber
Increase Jumping Power
Using cluster sets should be done carefully and with a long-term plan in mind. Just adding it to your existing routine and avoiding all straight sets won’t make your routine very good. Straight sets and the fatigue associated with it have a purpose for both powerlifters and bodybuilders alike. When you want to add cluster set configurations to your training, you must do so with a clear goal in mind.
To break up volume
Cluster sets can be used to break up higher rep sets and volume work. For example, 3×10 can be turned into 3x (2×5). What this means is after doing a set of 5, you would rest up to 30 seconds and then complete the other set of 5 and then do a full rest period after the 10th rep. This can limit form breakdown and maintain faster bar speeds. This is ideal for athletes who want to focus on speed.
Specific to powerlifting
Powerlifting is training for and the execution of a 1 rep max. The more you practice singles and the closer you train to practicing singles, the better you get at singles. These can be used in a peaking phase with doubles and triples turning 1×2/1×3 into 1x (1×1) and 1x (1x1x1). Or, it can be used to turn a given set of reps to pre-fatigue leading up to a cluster single at the end. If you want to have a cluster single with a set of 5, then you would turn 1×5 into 1x (1×4) (1×1)). This allows an athlete to practice singles at a certain effort level even with reduced loads.
To manage fatigue
Adding clusters can also be used on an “as needed” basis. If your form is breaking down, your bar speed is suffering, and you’re caught in the middle of a set that you’re overshooting – re-racking the bar and taking 30 seconds to compose yourself and recover may be the difference between pushing yourself too hard and saving yourself for another training session.
To Increase Fatigue
Often referred to as “myo – reps,” is using a high rep set to approach failure, then resting 15-30 seconds before doing another set of reps and trying to stay in a fatigued state. This is used for increasing total metabolic stress and can be a great time saver. An example of a myo set looks like
1×10 @ 9,Rest 15s, 1×5 @ 9, Rest 15s, 1×3 @ 9, Rest 15s, 1×2 @ 10.
Long Term Planning
Cluster’s shouldn’t be used for all sets and reps done. Straight sets have their purpose and shouldn’t be ignored entirely. Additionally, some people do not like them, as it makes them feel worse. With the squat, resting typically results in an increase in bar speed and power. However, with the deadlift, the first rep after a cluster rest period has slower speeds and higher impulse. Since some athletes do not psychologically enjoy them, they shouldn’t be given to everyone.
To manage fatigue
While some people use RPE to autoregulate load, clusters can be used on an “as needed” basis as well. Sometimes an athlete feels their technique is off, they lost their focus and breath and needed several seconds to gain their composure. While this shouldn’t be used as a method to slack off, this can be used as a way to come back and finish strong when something goes awry or if you have a terrible day. (Or someone walked in front of your camera filming your top set for the gram).
Most research on cluster sets are done with plyometrics and squats, showing increases in bar speed and power output as well as maintaining performance longer set to set than straight sets. The only downside to using clusters with squats is that you have to re-rack and walk the bar out several times which can get very tiring.
The reason a regular squat is more comfortable than a pause squat is that regular squats utilize the stretch-shortening cycle in the muscles of the leg. During the lowering, or eccentric phase, potential energy is stored in the muscles responsible for lowering you slowly into the squat which is then used when the athlete “bounces” out of the hole. With “touch n’ go” deadlifts, this same effect is utilized to a lesser effect. This makes the second rep and the reps following easier, where if you were to take a full reset or cluster it would make each rep difficult. Cluster rest periods end up causing the next rep to be slower and harder. This is more specific to powerlifting – because you only do one rep on the platform.
The bench press responds to clusters in a similar way to the deadlift, where the first rep completed after a rest period is slower, and some say it feels more difficult. However, peak speeds and power output are maintained longer and perform better than straight sets provided you can overcome the psychological feeling of the slow rep after your rest period.
About the author: Joshua Elliott is a Strength and Conditioning Coach who specializes in power training and powerlifting. To see more exercise science research, go follow @wolffslawfitness.