Lifting heavier weights makes your fast-twitch muscle fibers grow bigger than lifting lighter weights does.

39

Pro

46

Against

Evidence from Studies

Supporting (1)

39

Community contributions welcome

39

Heavy or Light

Systematic Review With Meta-Analysis

The study found that lifting heavier weights makes type II muscle fibers grow more compared to lifting lighter weights, which supports the claim.

Contradicting (1)

46

Community contributions welcome

46

The Effects of Low-Load Vs. High-Load Resistance Training on Muscle Fiber Hypertrophy: A Meta-Analysis

Systematic Review With Meta-Analysis

Human

2020 Aug

The study looked at lifting heavy weights versus lighter weights and found no proof that heavy weights make type II muscle fibers grow more, which goes against the claim.

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Similar Assertions

Lifting lighter weights with more reps might make your slow-twitch muscles grow bigger than lifting heavier weights with fewer reps.

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Lifting heavy weights might make your fast-twitch muscle fibers grow bigger than your slow-twitch ones, according to some new research.

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Lifting heavier weights might make your fast-twitch muscle fibers grow more than lighter weights, but the results aren't totally certain.

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Whether you lift light weights or heavy weights until you can’t do another rep, your muscle fibers don’t seem to grow significantly more with one than the other — but we can’t be sure because the results are too uncertain.

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