correlational
Analysis v1
Strong Support
Elite middle-distance runners with more of a certain muscle chemical (carnosine) tend to get worse, not better, after intense training and rest—meaning their performance drops instead of improving.
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Evidence from Studies
Supporting (1)
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Community contributions welcome
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Muscle fiber typology is associated with the incidence of overreaching in response to overload training.
Cohort Study
Human
2020 Oct 1Runners with more fast-twitch muscle fibers (shown by higher carnosine levels) were more likely to get overtrained and didn’t improve as much after rest, 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.