Most lifters have an opinion on rep ranges. They’ve read enough to know that 1–5 reps builds strength, 6–12 builds hypertrophy, 15–20 builds endurance-adjacent muscle. They structure their programs around these brackets and feel like they’re doing the science correctly.
They’re not wrong, exactly. But they’re solving the wrong problem.
The research on rep ranges - including work from Brad Schoenfeld’s lab and others studying hypertrophy mechanisms - generally shows that muscle growth happens across a wide range of rep schemes, provided sets are taken close to failure. That “close to failure” condition is doing almost all the work. The rep number is a distant second.
What this means in practice: a set of 10 where you stop at rep 7 because it’s getting uncomfortable is not a hypertrophy set. It’s a warm-up with extra steps. You could be doing triples or twenties and it wouldn’t matter - the stimulus is weak regardless.
Proximity to Failure Is the Variable Most People Underestimate
Reps in reserve (RIR) is a useful but frequently abused concept. Leaving 2–3 reps in reserve on a working set is legitimate programming - it allows higher volume without excessive fatigue. But most gym-goers aren’t stopping at 2 RIR because they’re managing fatigue strategically. They’re stopping because the weight got hard and hard feels like a sign to stop.
There’s a real gap between “this is difficult” and “I cannot complete another rep with controlled form.” Most people never reach the second threshold. They orbit the first one for years, making slow progress and attributing it to genetics, age, or needing a better program.
The Program Is Convenient to Blame
Switching from 3x10 to 5x5 every few months creates the feeling of change. New numbers, new energy, maybe new results for a few weeks because novelty briefly sharpens focus. Then the same habits take over and progress stalls again at roughly the same point.
A harder set of 8 will do more than a comfortable set of 5 on a “strength program” - not because 8 reps is magic, but because effort compounds in ways that rep prescriptions don’t.
The rep range question is worth understanding. But for most people training in commercial gyms, it’s a detail being used to avoid the more uncomfortable variable.