What is Cluster Training?
Cluster Training involves utilizing short intra-set rest periods (usually ranging between 10-30 seconds), we will be using 15 seconds, which will act to allow us to perform more reps with a heavier weight.
With cluster training, the design is all about the rest between reps, rather than between sets.
How do you do Cluster Training?
There are a number of ways you can set up cluster training, but the most important principle of this training methodology lies in the short rest intervals between reps, or multiples of reps. Make sure you re-rack the bar when you rest, and utilize the entirety of the rest period - both during and after your set.
We're going to get our reps in then rest. Get another rep in then rest. And then get one more rep and rest. And that will make up one set. This work-to-rest program design is called intra-set rest and has a lot more rest between reps.
Why do we need more rest? Because rest allows us to lift more weight and hit higher tonnages in a training block.
What the hell is "tonnage" and why is it important?
Tonnage is a term that quantifies overall load used during a period of time.
Tonnage = Weight X Reps X Sets
Tonnage has been used for decades as a qualifier for national and international levels in weightlifting. Theoretically, if a person can accumulate a higher total of weight in a period of time, they should be able to compete at a higher level, become much stronger.
How do we manipulate sets and reps to achieve a higher overall tonnage?
We can do 10 sets of 10 to achieve more morphological changes, like body composition of hypertrophy. Or we can utilize 10 sets of 3 reps to achieve more neuronal changes; such as, power and force production.
There is an interesting concept called Prilipen's chart which describes the volume people can hit at specific intensities in a training session, please refer to the image below:
The science behind cluster training.
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). 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).
Below are a few cluster set/rep schemes we may program for you depending on your individual fitness goals.
Before we move onto that, it's important to note that you can utilize cluster training on most exercises, but seeing as we're looking for mostly strength and muscular gains, it makes sense that the best exercises to use are the bigger compound, barbell exercises,
Okay, let's look at some ways to set up your cluster training. The first thing you'll notice is that the sets/rep schemes for clusters are written in a weird way. Don't freak out, they're quite easy to interpret.
POWER FOCUSED CLUSTER: 5(4x2) - 10 sec w/ 5RM
In this set up, you'll do 5 total cluster (the first number), and each cluster is going to consist of 4 mini sets of 2 reps (the bracketed numbers). You're going to rest 10 seconds in between each mini set, and you're going to use around your 5RM load.
HYPERTROPHY FOCUSED CLUSTER: 5(3x3) - 15 sec w/ 6RM
Again, this follows in the process as the example above, except that in this set up you're going to do 3 mini sets consisting of 3 reps, with a 6RM. This will allow you to do 9 total reps with a 6RM, and skew the training effect more towards gaining muscular mass aka hypertrophy.
"THE SPICY CLUSTER"
3-4 sets of AMRAP until you hit 15 total reps - 30s w/ 85% of 1RM
In this example you're going to find a weight that's around 85% of your 1RM, and you're going to do as many reps as possible (without going to complete failure) before racking the bar and resting for 30 seconds. After the short rest you're going to again try and get as many reps as you can, before re-racking the bar and resting for another 30 seconds. Continue in this fashion until you hit a total of 15 reps. Repeat for 3-4 total clusters. Typically you should hit anywhere from 5-8 reps in your first mini set, and then have the reps slowly decrease for each subsequent mini set.
With this data, we can formulate strategies to bang out more out of our training if:
Cluster Training allows us to push past fatigue.
Fatigue is the limiting factor when trying to hit and complete more reps. This is the basic premise as to why we cannot go on forever at a specific intensity. That fatigue could come from central nervous system (CNS) fatigue or from muscular system fatigue. Either way, we are going to have to stop at a certain point no matter how much we want to keep going, which is frustrating.
If we have 3 reps, adding more rest between reps is how we can squeeze 91% when normally we can only handle 90% for 3 sets of 3 reps.
Let's talk about Relative Intensity and see how it relates:
Believe it or not, we do not work at 100% for the entire block. We progress from 70%, 80%, 90% and finish at 100%. With 100% being your 1 rep max.
Working sub-maximally has incredible benefits.
Working sub-maximally builds motor patterns in response to the stress and begins the progressive overload over the four weeks. When we get the fourth week, we are supposed to be able to hit 90-92.5% of our max for 3 reps.
The intent is to handle higher intensities for increased volumes so we can accumulate more tonnage. If fatigue is coming from either the muscular system (replenishment of ATP/PC) or from the central nervous system (update or transmission of neurotransmitters) we can override that by allowing for rest in between sets.
Our training performance all comes down to our limiting factors. If our limiting factors are not as limiting then we can lift heavier weights than we normally can. And if we can use heavier weights than normal, we will obviously become stronger. Gainz.