Perhaps the most important factor in developing a long term training program is that it is designed to introduce appropriate training variables, in a systematic/logical order, so as to stimulate the improvement of specific physiological qualities. Variation is essential in development as it will stimulate adaptation, encourage recovery, avoid overtraining, potentiate subsequent phases, and lead to elevations in performance (1).
Generally there are many ways to introduce training variation into a training programme including but not limited to: exercise selection, training load, intensity, volume, time under tension, or rest periods used. Changes in training program design may lead to more rapid increases in performance; the more familiar the athlete is with a task the slower performance increases may be (2). This is especially true when dealing with more advances and elite clients.
Set Structure is often overlooked in the design of new strength and conditioning programs. It is most common for repetitions be performed continuously for a specific number for instance 5 sets of 5 or 3 sets of 10 are common configurations. However there are other methods for performing given reps in a set that may allow for greater power outputs and greater overall work completed.
Enter Cluster training. Cluster training is a set and rep configuration whereby the athlete will take short pauses/rests between reps that will allow them to complete more reps with a higher percentage of their maximum weight. Typically there are 2 types to this configuration undulated and traditional. Undulated clusters involve short rests between reps of 10-30s with the weight increasing in a pyramid like fashion with each rep. Similarly traditional clusters include short rests of 10-30s between reps with the same weight for each repetition. Both methods are useful in the training of more intermediate and elite trainees (1).
Through the utilization of inter-rep rests the athlete is able to experience partial recovery between reps and thus have higher power outputs on each rep as compared to traditional continuous rep systems. This rest allows for higher peak power output, higher bar velocity, and higher peak barbell displacement. This type of training is useful when wanting to develop neuromuscular power as athletes will experience less repetition-induced fatigue allowing for higher overall repetition power. The short rests help to stop the accumulation of blood lactate, which is the enemy of power development. Accumulation of lactate effects muscle contraction negatively through impairments of ATP generation (1).
Furthermore cluster training may be useful with Olympic lifts, and other lifts that require high coordination and skill. This is because it will allow the athlete short periods of time to refocus on technique and thus produce greater quality reps and ultimately increase the amount of good reps in a training session.
When programming a cluster set a back slash is typically used to highlight the fact that a cluster set is being used for instance a programmed exercise may look like this:
A1 Power Clean From Ground – 3 sets 5/1 Reps
This would indicate that the athlete is performing 3 sets of 5 total reps clustered.
So when choosing a cluster configuration it may be most useful in the power phases of a program as peak power and bar speed velocities are maximized for a greater number of reps. Or you may want to use this method when programming lifts with higher complexity such as the Olympic lifts for your clients which will lead to a larger number quality of reps. Try it out for yourself.
1. Haff GG, Hobbs RT, Haff EE, Sands WA, Pierce KC, and Stone MH. Cluster training: a novel method for introducing training program variation. Strength & Conditioning Journal 30: 67-76, 2008.
2. Hodges NJ, Hayes S, Horn RR, and Williams AM. Changes in coordination, control and outcome as a result of extended practice on a novel motor skill. Ergonomics 48: 1672-1685, 2005.