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Claim
Strong Support
correlational
Analysis v3

In healthy young men, performing resistance training twice a week for six weeks, using either 10 or 20 repetitions per set to failure, leads to similar increases in muscle thickness of the thigh...

47
Pro
0
Against

Mechanism

Synthesis from 1 study

How it works

Pushing your muscles until they can't do another rep — whether with heavy or light weights — creates a chemical environment inside them that tells them to build more protein. This extra protein makes the muscle fibers thicker, and that’s why both training styles lead to similar growth. The key...

Most probable mechanism

In Simple Terms

When you lift weights until you can't do another rep, your muscles run out of energy and build up waste products. This triggers signals inside the muscle cells that tell them to make more protein, which causes the muscle fibers to grow thicker over time. It doesn't matter if you use heavier weights for fewer reps or lighter weights for more reps — as long as you push to exhaustion, the same cellular signals turn on and lead to similar muscle growth.

Causal chain
1

Resistance training to concentric failure induces metabolic stress through accumulation of metabolites such as lactate, hydrogen ions, and inorganic phosphate within muscle fibers

Supported by evidence
which leads to
2

Metabolic stress activates intracellular signaling pathways including mTORC1 and MAPK, which increase the rate of muscle protein synthesis

Supported by evidence
which leads to
3

Elevated protein synthesis exceeds baseline protein breakdown, resulting in net accretion of myofibrillar proteins and increased muscle fiber cross-sectional area

Supported by evidence
which leads to
4

Increased myofibrillar protein content manifests as measurable thickening of the vastus lateralis muscle

Supported by evidence

Evidence from Studies

Supporting (1)

47

Community contributions welcome

47

Similar improvements in skeletal muscle oxidative capacity after moderate (10-RM) and high repetition (20-RM) resistance training.

Randomized Controlled Trial
Human
2025 Dec

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.

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Source Study

Similar improvements in skeletal muscle oxidative capacity after moderate (10-RM) and high repetition (20-RM) resistance training.

Score: 47
DOI: 10.1016/j.jsams.2025.06.007

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