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Runners' Muscles Get Super Damaged — But New Clues Show How Bad

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Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms

Summary

When elite runners race for 24 hours straight, their muscles get smashed — so much that doctors call it rhabdomyolysis. Scientists checked blood markers to see which ones best show how hurt the muscles are.

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Surprising Findings

Creatine kinase (CK), the long-standing gold standard for muscle damage, showed no correlation with persistent muscle weakness 24 hours after the race.

For decades, CK has been used in clinics and sports science to gauge muscle injury—yet here, it failed completely while microRNAs succeeded.

Practical Takeaways

If you're training for an ultra, monitor muscle weakness—not just CK levels—after long events, and seek medical help if you're still severely weak 24 hours later.

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Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms

Summary

When elite runners race for 24 hours straight, their muscles get smashed — so much that doctors call it rhabdomyolysis. Scientists checked blood markers to see which ones best show how hurt the muscles are.

Sign up to see full results

Get access to research results, context, and detailed analysis.

Surprising Findings

Creatine kinase (CK), the long-standing gold standard for muscle damage, showed no correlation with persistent muscle weakness 24 hours after the race.

For decades, CK has been used in clinics and sports science to gauge muscle injury—yet here, it failed completely while microRNAs succeeded.

Practical Takeaways

If you're training for an ultra, monitor muscle weakness—not just CK levels—after long events, and seek medical help if you're still severely weak 24 hours later.

low confidence

Unlock Full Study Analysis

Sign up free to access quality scores, evidence strength analysis, and detailed methodology breakdowns.

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Publication

DOI:10.1111/sms.14000

PubMed:34021921

Related Content

Claims (7)

After running for 24 hours straight, elite runners can't jump as high right after finishing—sometimes less than one-fifth of their normal jump height.

After running for 24 hours, elite runners have extremely high levels of a blood marker that signals their muscles are breaking down, and those levels stay high the next day.

After a 24-hour race, the blood of elite runners shows massive spikes in six tiny molecules that come from muscle tissue—some up to over 100,000 times higher than normal.

After a 24-hour race, the levels of certain tiny muscle molecules in the blood match up better with how weak the runners still feel the next day than the usual muscle damage markers do.

Every single elite runner in this study ended up with a serious condition called rhabdomyolysis after running for 24 hours straight.