WHAT IS IT?
Cluster sets are a way of condensing volume into intense bouts of manageable rep targets separated by brief rest intervals. The load and intensity are preserved such that more effective reps can be achieved than with traditional, straight sets.
HOW TO TRACK PROGRESSION?
When variables like range of motion, tempo, and intent, progress can be tracked week-to-week through load increases, the number of sets achieved until technical failure, and/or RPE/total reps on the last cluster set (if pushing beyond the rep target). Rest intervals can also be increased/reduced in order to modify the intensity accordingly.
WHO SHOULD USE IT?
Cluster sets are versatile, and easy to track and progress. They can be incredibly beneficial for breaking through a plateau in volume at a certain weight while allowing for technical perfection with fewer reps at a time. Using clusters as an intensity technique should be reserved for advanced trainees, but clusters can also be used as a way to circumvent technical breakdowns as sets approach failure in beginners and intermediates.
WHO SHOULD NOT USE IT?
Beyond-failure training should not be used by those who have a lower work capacity and/or difficulty maintaining technical prowess when fatigued, as pushing to failure (and beyond) can drastically increase injury risk. The aggressive work-to-rest ratio (as compared to straight sets) places higher demands on the trainee's cardiovascular, neuromuscular, and musculoskeletal systems. As mentioned above, beginners and intermediates should refrain from using cluster sets as a way of increasing intensity.
WHEN TO USE IT?
Clusters can be used relatively liberally given the strict cap placed on total volume/workload. Whereas many other intensity techniques tend to be detrimental if used too early in a mesocycle, cluster sets can be a mainstay from the first week due to the ability to progress on them over a long duration of time, and via multiple routes, before stalling.
WHEN NOT TO USE IT?
When in periods of intentional reductions of metabolic and intensity-related stressors (such as a deloads, maintenance period, or return from injury), performing cluster sets can be detrimental to the phasic goals. There are also times when straight sets will be the preferred method of volume accumulation (such as when maximizing total workload/volume-load or driving progression through volume/set PRs). Cluster sets are, no doubt, versatile but they should not be exclusively relied upon.
HOW TO USE IT?
Clusters are best used with a primary/secondary main movement to maximize effective reps or with accessory movements to build metabolite accumulation. There will be obvious crossover between these use cases, but it will be important to clearly distinguish the goal underlying inclusion of cluster sets before adding them into your program. Additionally, performing clusters with unilateral variations provides a huge stimulus with virtually no rest due to being able to alternate work and rest cycles.
Examples:
Leg Press- 5x5 with ~12RM and 20 sec rest
Single Arm Preacher Curls- 6x3 each with ~10RM and rest while the other arm is going
V Squat Goodmornings- 4x6 with ~15RM with 30 sec rest
HOW NOT TO USE IT?
Cluster sets should not be used with any variation that has high levels of movement variability, low intrinsic stability, high latency/complexity with set-up, and/or unpredictable failure points. Clusters are best executed when repetition quality is standardized within a stable environment leading to unsurprising results.
Examples:
Barbell Front Squats- Complex setup (having to walk bar in and out of rack each time) as well as multiple possible failure points (bar slips off shoulders, weak upper back, etc)
DB Walking Lunges- Inefficient use of energy (alternating rather than single leg) as well as low intrinsic stability
Power Cleans- High variability and complexity with low stability and unpredictable outcomes (when it relates to clusters as an intensity technique)
BENEFITS OF THE TECHNIQUE:
- Increased effective reps with lower total training time
- Can lower systemic fatigue compared to straight sets when equalizing for effective reps
- More logistical practicality
- Can actually reduce risk of injury for trainees who experience technical lapses with straight sets close to failure
- Very easy to track progress
- Can be implemented effectively within almost any period of a mesocycle rather than just the latter weeks
DRAWBACKS OF THE TECHNIQUE:
- Not applicable for all exercises due to the prerequisites mentioned above
- Sustained progress is dependent on the trainee's ability to train at high intensities over multiple weeks
- Not all trainee's will be able to generate the necessary growth stimulus from cluster sets alone; they will need more volume even if it's at lower intensities