Cluster or rest-pause training involves using short inter-set rest periods of anywhere from 10–30 seconds to produce more powerful repetitions or more repetitions with a heavy weight. Big proponents of cluster training include Charles Poliquin, Christian Thibaudeau, and Ashley Jones. I like using clusters because they are a bit different, they're extremely challenging, and above all, they work! In the following article, I'm going to share the theory behind cluster training and discuss the various types of clusters I've used with great results.
Warning! The exact science behind the efficacy of cluster training has yet to be fully understood. For those not interested in the theory behind cluster training, skip to the ‘types of clusters’ section. For those who want to indulge their inner geek, keep reading!
The ATP-PC energy system is responsible for energy production for the first 10–15 seconds of maximal exercise. Therefore, it's important for strength and power events. To fully replenish the ATP-PC system, it takes about three minutes, but initial recovery is much quicker. After 30 seconds, it can be 70 percent recovered. By using short inter-set rest periods, athletes can perform more reps with a heavier weight or more powerful reps with a sub-maximal weight when training for power.
Post-activation potentiation (PAP) is an increase in force production of the skeletal muscle following a previous muscular contraction (Sale 2002). The science behind PAP warrants another article, so I won’t get bogged down in it. Essentially, every rep you perform has an excitatory effect on the muscles and nervous system involved. If there is little fatigue, a more forceful contraction can be produced subsequently. This leads to my next point…
Fitness fatigue theory (lactate)
Any training stimulus has two effects—a fitness effect and a fatigue effect. Your performance is a balance between these two opposing factors (Chiu 2003). PAP takes advantage of the heightened fitness to increase force production, but if you perform a set with many reps, more fatigue will be involved and performance will decrease. So with traditional sets, more fatigue is accumulated in the form of lactic acid, thus you can't take advantage of the fitness effect or PAP. With cluster training, there is little fatigue, so you can make the most of PAP and each rep should be more explosive than the last (Haff 2008).
Types of clusters—strength
Classic 5 X 1 cluster: Using a load that is about 90 percent of your one rep max (RM), perform one rep, rack or drop the bar, rest 10–15 seconds, and then repeat for five total reps and a total rest of three minutes. Repeat for the desired number of sets (often written as 5(1)). This method has you lifting five reps with what is roughly your 3–4RM and always increases maximum strength.
Types of clusters—hypertrophy
It is believed that for hypertrophy to take place lactic acid is required (Schoenfeld 2010), so these cluster techniques initially require higher reps before a short rest. These techniques have the benefit of improving both strength and power.
Thibaudeau’s extended fives: Using a 6RM load, perform five reps, rest for 10–15 seconds, and perform two more reps. Rest another 10–15 seconds and perform one final rep. Rest for 2–3 minutes and repeat for the desired number of sets. Make sure to rack the weight for every rest period! With this technique, you perform eight reps with your 6RM—a brilliant stimulus for hypertrophy.
Verkhoshansky extended set: Here you perform 15 reps with 85 percent of your 1RM with inter-set rest periods of 30–45 seconds. This is usually done as a finisher after other strength work and can be brutal. You perform as many reps as possible, rest briefly, and then go again in this fashion until you hit 15 reps. It may go something like this: eight reps, 30 seconds rest, three reps, 30 seconds rest, two reps, 40 seconds rest, one rep, 45 seconds rest, one final rep, and then run for the sick bucket (Verkhoshansky 1967).
Research has shown that cluster training may increase force or velocity when training for power (Haff 2003, Haff 2008, Hansen 2011). Cluster training is believed to be most effective when training for power. Common ways of training for power include:
- 4 X 2 cluster: Perform four cluster sets of two reps with ten seconds rest between cluster sets and three minutes rest between sets. The load depends on programming but will normally range from 40–60 percent of your 1RM.
- 5 X 1 cluster: Perform one rep, rest for 30 seconds, repeat for five total reps, and then rest three minutes. Repeat for the desired number of reps.
When to use clusters
Clusters are best used with compound barbell exercises. You could do it with dumbbells, but having to pick the weights up and get set before each cluster set eats into your time and is a nuisance. Ideally, use exercises where you can rack the weight easily (bench, squat) or exercises where you can rest the bar on the floor after each rep (Olympic lifts, deadlifts). Cluster training is pretty demanding and should only be used with advanced trainers. I prefer to use them if a tough week is planned where I know there is a subsequent deload planned. Cluster training is a high intensity and high volume technique so program accordingly.
Cluster training is a novel method that can be used for strength, power, and hypertrophy. It can be an exciting new stimulus for athletes and it works. Olympic lifters have been using this technique without even intending to and it certainly hasn’t hurt them! Give some of these techniques a try, and I’m certain that you'll be one step closer to your goals.
- Chiu LZF, et al (2003) The fitness-fatigue model revisited: Implications for planning short- and long-term training. Strength and Conditioning Journal 25(6):42–51.
- Haff GG, et al (2003) Effects of different set configurations on barbell velocity and displacement during a clean pull. Journal of Strength and Conditioning Research 17(1):95–103.
- Haff GG, et al (2008) Cluster training: a novel method for introducing training program variation. Strength and Conditioning Journal 30(1):67–76.
- Hansen KT, et al (2011) Does Cluster Loading Enhance Lower Body Power Development in Preseason Preparation of Elite Rugby Union Players Journal of Strength and Conditioning Research 25(8):2118–26.
- Sale DG (2002) Post-activation potentiation: Role in human performance. Exercise and Sports Science Reviews 30:138–43.
- Schoenfeld BJ (2010) The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research 24(10):2857–72.
- Verkhoshansky Y (1967) Special Strength Training: Manual for Coaches.