How much your biceps stretch during your first hard workout tells you how sore and weak you’ll feel the next day—but not how much enzyme leaks into your blood.
Scientific Claim
In untrained men, the magnitude of muscle lengthening during the first bout of eccentric elbow flexor contractions predicts the severity of muscle damage markers, including strength loss and inflammation, but not serum creatine kinase levels.
Original Statement
“A significant correlation was found between the percent change in distal MTJ displacement... and the magnitude of decrease in MVC torque... and the magnitude of change in peak ultrasound echo intensity; however, no significant correlation was found between the MTJ displacement and changes in other variables... (CK: r = 0.260).”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The claim correctly uses 'predicts' in a correlational context and distinguishes between markers based on reported r-values. No causal language is used.
Evidence from Studies
Supporting (0)
Contradicting (1)
Reduced muscle lengthening during eccentric contractions as a mechanism underpinning the repeated-bout effect.
The study found that when muscles don’t stretch as much during exercise the second time, they get less damaged—including less CK in the blood—so the claim that muscle stretch size predicts damage but not CK is wrong.