Arnold Schwarzenegger is never short on training wisdom, as he consistently breaks down the more nuanced concepts in fitness. On February 25, 2025, he compared the muscle-building gains of cluster sets versus straight sets.
Cluster sets involve you performing a certain number of reps, and then resting for a few seconds before doing the next cluster of reps. Straight sets are as the name suggests, straightforward. You simply perform a set number of reps and then rest at the end of the set.
Arnold Schwarzenegger was keenly familiar with both of these training strategies as a former seven-time Mr. Olympia champion. And even today, he still trains seven days a week, prioritizing the pump, while ensuring he stays healthy.
Arnold Schwarzenegger Compares Muscle-Building Gains of Cluster Sets vs Straight Sets
In his daily Arnold’s Pump Club Newsletter, Schwarzenegger revealed that straight sets can result in similar muscle growth compared to advanced training systems like cluster sets.
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“Are Regular Sets Enough To Build Muscle?
If you want bigger, stronger muscles, do you need complex training methods to deliver better results?A new study suggests that traditional straight sets lead to as much muscle growth as a more advanced training method.”
The study at hand saw scientists compare cluster sets with straight sets. One group performed three clusters of four reps separated by 20 seconds. Then, the straight set group performed 12 reps with three minutes of rest between sets.
“The researchers compared cluster sets, which involve breaking up a set into smaller “mini-sets” with short rest periods, to traditional sets, where you complete all reps before resting.”
The study randomly assigned resistance-trained individuals to either method, performing volume- and effort-matched workouts. The cluster set group performed 3 clusters of four reps, separated by 20 seconds. In other words, they would perform three reps, rest for 20 seconds, then another three reps, 20 more seconds of rest, and so forth until 12 reps were completed. That was one cluster set, and five sets were completed (with three minutes of rest between sets).
On the other hand, the straight-set group simply performed five sets of 12 reps with three minutes of rest between sets.
After months of training in this manner, both groups saw comparable increases in muscle gain.
“After months of training, both groups saw comparable increases in muscle gain. This means whether you spread out your reps with short breaks or complete them all at once, your muscles will still grow—as long as you’re pushing with the same effort and total volume.”
With these findings in mind, Schwarzenegger says you’re better off focusing on consistency, progression, and intensity, rather than relying on different training systems like cluster sets.
“The lesson: progressing your workout and maximizing intensity matters more than adding every special training technique.
Instead of overthinking every variable and exercise, focus on consistency, progression, and intensity.”
From complex training systems to easy-to-apply bodyweight workouts for gains, Arnold Schwarzenegger continues to give back to the fitness and bodybuilding community. If you’re fretting over which methods to implement in training, Schwarzenegger says not to worry about that. Instead, he emphasized that your primary concerns should be maximizing consistency, progression, and intensity for muscle growth.
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