When people who are already fit push themselves as hard as they can during weight training, it doesn't matter if they lift heavy weights for a few reps or lighter weights for many reps—both ways build muscle about the same.
Evidence from Studies
Supporting (3)
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Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis
The study found that lifting weights until you can't do more reps leads to similar muscle growth whether you use light weights for many reps or heavy weights for few reps, which matches the claim.
This study found that lifting light weights for many reps and heavy weights for few reps, both done until you can't lift anymore, made muscles grow about the same size in people who already work out.
Divergent Strength Gains but Similar Hypertrophy After Low-Load and High-Load Resistance Exercise Training in Trained Individuals: Many Roads Lead to Rome.
The study shows that lifting light weights many times or heavy weights a few times, both until you can't do more, makes muscles grow similarly in people who already train.
Contradicting (0)
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Gold Standard Evidence Needed
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