Cluster Sets for Developing Power

by Brett Holland, PT, DPT, CSCS

Cluster sets are just a fancy word for resting between reps in a set.  For example in a typical exercise you might perform 10 repetitions continuously without rest.   The 10th repetition is (usually)more difficult and you may experience an exercise burn towards the end.   In a cluster set you might do 5 repetitions then rest 10 seconds, then do 5 more repetitions.    It is relatively widely accepted in the strength and conditioning field that exercises to develop power should be done in a non-fatigued state.  In addition, power exercises are generally done with lighter weight (30-50% of repetition maximum) and with high velocity.  Baker and Newton present an excellent table describing intensity zones and training effects, if you are interested in learning more I recommend reading ” Methods to increase the effectiveness of maximal power training for the upper body”[1].   Some examples of power exercises include:

• Medicine ball throws
• Ballistic bench throws
• Barbell Squat Jumps
• Olympic lifts and variations
• Notice how with these exercises there is a high degree of acceleration

As I previously mentioned, the goal of power exercises is usually maximal performance.  Simply meaning, you want to perform your best on each and every repetition.  Fatigue hampers performance, therefore we try and avoid fatigue when performing exercises to develop power.  Baker and Newton recommend using low repetitions during power exercises.  Specifically, 2-3 repetitions for maximal power exercises and 3-5 repetitions for general power [1].

How can cluster sets help us?

A 2015 study examined the effects of resting between repetitions during the ballistic bench throw and its effects on upper body power [2].

What did they compare:

• 3 groups
• 1 group performed 15 continuous repetitions (too many for my liking)
• 1 group performed 6 seconds of rest between each repetition (15)
• 1 group performed 12 seconds of rest between each repetition
• They tested loads of 30%,40%, and 50% of 1RM.

What did the researchers find?

• The greater the load the more velocity decreases in a set (50% creates greater fatigue than 30%)
• Intra-rep rest was better at maintaining performance than continuous repetitions
• 6 seconds of intra-rep rest had relatively negligible effects early in the sets
• 12 seconds of intra-rep rest was the best across the board for maintaining maximal performance
• Cluster sets were more beneficial as you get higher into the reps.  The authors stated, “Similar results were obtained in this study for the IRR12 protocol.  In comparison with the traditional CR, in our study, movement velocity was significantly higher after repetition 4 at 30%RM and 40%RM and after repetition 2 at 50%RM”[2].

What is the take home message of this article?

• Cluster sets are another tool strength and conditioning coaches can use to maintain power/performance
• Cluster sets can help trainees perform more repetitions at maximal performance in a session
• Cluster sets are not as effective if the repetitions are low

References:

1.  Baker D, Newton RU. Methods to increase the effectiveness of maximal power training for the upper body. Strength Cond J 27: 24–32, 2005.
2. García-Ramos, Amador, Paulino Padial, G. Gregory Haff, Javier Argüelles-Cienfuegos, Miguel García-Ramos, Javier Conde-Pipó, and Belén Feriche. “Effect of Different Interrepetition Rest Periods on Barbell Velocity Loss During the Ballistic Bench Press Exercise.” Journal of Strength and Conditioning Research 29.9 (2015): 2388-396. NSCA