What handball players should know about volume & intensity and why cluster sets are the cheat code, when you want to do more reps with the same weight.
Volume and intensity are inversely related - usually you can’t do more reps and more weight. But there seems to be a cheat code: Cluster Sets. They let you do more of both. But this is not the only advantage of cluster sets.
VOLUME & INTENSITY
When you read a training program, usually besides the exercises there is also some information about the amount of work (i. e. sets, reps or distance) - that is what we can consider as volume. But if you only have these numbers, one important information is missing for you to train optimally. You also need to know how much weight (i.e. % of your 1-Repetition Maximum) you should put on the bar or how fast you should run for the given distance. These metrics are examples of the intensity of the workout. In the following example (Figure 1) you’ll find all the metrics we’ve talked about.
It’s important to understand that volume and intensity are interrelated. The more intensity you aim for, the less volume you can afford and vice versa (see Figure 2).
If we want to give some numbers here, you can see the percent-repetition chart (Figure 3). Although these numbers are only a rough estimation and depend on other factors like gender or familiarity with the exercise, they show the interaction of volume and intensity. If you train at 100% of your 1-repetition maximum, chances are high that you will - surprise surprise - manage one repetition. However, if you train with 80% of your 1-repetition maximum, you definitely manage more than just one repetition.
The same applies to speed or endurance training. If you want to train at maximum speed, you can’t keep increasing the duration of each repetition. After a few seconds your speed will drop and you will no longer be training at maximum speed.
And there's something else you should keep in mind. There are other factors that can affect intensity - such as intent, which basically means how fast and hard you try to accelerate the external resistance or your body. But for now, the above explanations are enough to show you the basic concept of volume and intensity. Now let's move on and introduce you to a concept called cluster sets and why we use it.
What are cluster sets? Well first, when we look at different training programs, next to sets, reps, and intensity there is usually also a given rest period. We see a lot of different definitions for rest. And this is even the case in the scientific literature. Traditionally, we train some repetitions until just before failure, rest for a certain amount of time, and then try to repeat them (Figure 4). In the following example, we do four reps, rest for 120 seconds, and repeat the four reps.
If we divide these sets of four repetitions into two parts of 2 repetitions with a small rest of 15 seconds, rest for 120 seconds and repeat the same 2 subsets of 2 repetitions, we speak of clusters or cluster sets. (Figure 5)
If we want to be crazy, we can split these first 4 reps into 4 individual reps with 15 seconds mini breaks (intra-set rest) in between. The rest between the two sets is still the same 120 seconds. (Figure 6)
But why should you do cluster sets? Here are 3 reasons why we like to include cluster sets in our training programs.
ADVANTAGES OF CLUSTER SETS
As we know from the first chapter, intensity and reps are closely connected. And if we assume that the 4 reps in the example from the previous chapter are with a weight of 87.5% of 1RM, we can’t do 5 reps instead of 4. I know, there are some people out there who can lift 5 reps with 87.5% but this is just an example for understanding the concept. But if we add an additional short break after 2 reps, eventually we can do another 3 reps (5 in summary) or we can manage 90% of 1RM for 2x2 reps.
This is the most common reason for incorporating cluster sets into a training program: More reps with the same weight or more weight with the same amount of reps.
Another reason or advantage could be bar speed. We also mentioned that there are other factors that can influence the intensity, such as intent. Intent is something that is closely related to bar speed. In sports, the time we have to generate the force is usually limited. And this is where the force-velocity curve comes into play (Figure 7). The faster you move, the less force you can generate and vice versa.
In Figure 8 you can see a set of 4 repetitions in an exercise with the measured velocity of the barbell in m/s. I’m sure you can immediately see the drop in velocity between rep 3 and 4. And if our goal is to train in a certain area of the force velocity curve, we stopped after rep 3 and rest until we can do more reps at the same velocity.
This is another reason why incorporating cluster sets might be useful. Higher Intent can equal faster bar speed. An example might be to split 4 reps into 4 singles with 15 seconds rest between (Figure 9). Hopefully we can keep the velocity up to rep number 4.
The above two main reasons for training with cluster sets are performance related. This means that cluster sets are a method for advanced athletes. However, we would like to add another advantage of cluster sets for someone who has just started training.
When you first walk into a gym and ask for a workout program, 9 times out of 10 you'll get a program of 2-3 sets of 15 to 20 repetitions of hopefully some basic exercises like deadlifts or squats. But these exercises take some time to learn the proper technique. So the question arises: are 2-3 sets enough to learn the technique? You can argue that this is one of the reasons why 20 reps might be useful. But take a step back and think about it. Wouldn't it be better to break up those 20 reps into smaller segments of 5 reps with a small rest in between (who likes 20reps anyway...)? In this case, you will get additional opportunities to focus on the things that are important for your technique. The goal is not to increase the weight for the same number of reps. You just need to focus for 5 reps, then pause for a few seconds to refocus and do the next 5 reps. This is why we incorporate cluster sets into our basic handball program. So you can do more quality repeats.
PRACTICAL APPLICATION & LIMITATIONS
When we summarize the current research (see below for some examples) on this topic, we find a large body of evidence supporting the use of cluster sets to maintain or increase acute performance-related variables such as jump height, strength, speed, and power, and to allow for greater training volume with the same load.
Because there is wide variability in the protocols used in current studies of cluster sets, it is difficult to find general guidelines for the best cluster set protocols.
However, based on research and our own practical experience, we most often use the following structure for two main reasons:
BETTER PERFORMANCE / MORE VOLUME:
1-4 reps per cluster
10 to 30 seconds rest between clusters
2 to 4 clusters
MORE QUALITY REPS
4 to 6 reps per cluster
10 to 30 seconds rest between clusters
2 to 4 clusters
Check out our Fundamental Strength Training for Handball Program were we use the advantages of cluster sets.
Latella C, Teo WP, Drinkwater EJ, Kendall K, Haff GG. The Acute Neuromuscular Responses to Cluster Set Resistance Training: A Systematic Review and Meta-Analysis. Sports Med. 2019 Dec;49(12):1861-1877. doi: 10.1007/s40279-019-01172-z