The truth about how many reps you need to build muscle"

19 Mar 2026 · 1 min

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In this concise fitness monologue, Eric Roberts argues that muscle growth is driven almost exclusively by the final two to three repetitions of a set, where the load is extremely challenging. He uses a runway‑plane analogy to illustrate that the earlier repetitions serve only as a “runway” and do not contribute to hypertrophy. Consequently, he advises lifters to ensure those last reps are very difficult by increasing the weight, regardless of the total number of reps performed, because without those hard reps the muscles are not being effectively stimulated.

Chapters

You only need to do 2 to 3 reps to build muscle. Let me explain. Most people will do 12 reps for an exercise, and what they don't understand is the first 9 or 10 reps, those aren't building muscle. It's like a plane taking off on a runway. Those first 9 to 10 reps are the runway. You need it for the plane to take off, But those last 2 to 3 reps where it's incredibly difficult and you can barely move the weight, that's when the plane actually takes off. And those are the only reps that you build muscle. So when you're doing your exercises, if the last 2 to 3 reps aren't incredibly difficult, then you're not building muscle. And you need to lift heavier weight for that exercise for however many reps you're doing moving forward.