When people lift weights until they can't do another rep, their muscles grow about the same amount whether they use heavy or light weights — and how much they grow depends more on their own body than on how heavy the weights are.

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Evidence from Studies

Supporting (1)

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Resistance training load does not determine resistance training-induced hypertrophy across upper and lower limbs in healthy young males.

Randomized Controlled Trial

Human

2025 Dec 31

When people lift weights until they can't do any more, their muscles grow similarly in their arms and legs—no matter if they use heavy or light weights—because their body’s natural biology matters more than how heavy the weights are.

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No contradicting evidence found

Source Study

Resistance training load does not determine resistance training-induced hypertrophy across upper and lower limbs in healthy young males.

Score: 46

DOI: 10.1113/JP289684

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