Lifting weights for three months makes the muscle fibers in young men's biceps get bigger — both the endurance-type and power-type fibers.

31

Pro

0

Against

Evidence from Studies

Supporting (1)

31

Community contributions welcome

31

Muscle fiber hypertrophy, hyperplasia, and capillary density in college men after resistance training.

Cross-Sectional Study

Human

1996 Nov

The study looked at college guys doing weight training for 12 weeks and found their biceps muscle fibers got bigger, just like the claim says.

Contradicting (0)

0

Community contributions welcome

No contradicting evidence found

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.

Source Study

Muscle fiber hypertrophy, hyperplasia, and capillary density in college men after resistance training.

Score: 31

DOI: 10.1152/JAPPL.1996.81.5.2004

Similar Assertions

Lifting weights for three months didn’t increase the number of muscle fibers in young guys’ biceps, so their muscles got bigger without adding new fibers.

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When young men who don't normally exercise do eight weeks of weight training, their fast-twitch muscle fibers get bigger, but their slow-twitch fibers stay the same size and the overall mix of muscle types doesn't change.

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When people lift weights, their arm and leg muscles show similar changes in muscle fiber numbers — and in both, we don’t see clear signs of new muscle fibers forming.

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