It’s not that slow lowering of weights damages muscles—it’s that your muscles aren’t used to it. Once they get used to it, no damage happens, even if you do the same move hard.

Scientific Claim

The muscle damage response to eccentric exercise is not inherent to the eccentric contraction itself, but is primarily triggered by unaccustomed exposure, as evidenced by the absence of damage biomarkers after repeated sessions despite identical mechanical load.

Original Statement

“Collectively, we believe that muscle unaccustomedness to high-intensity eccentric exercise, and not eccentric exercise per se, is the trigger for muscle damage as indicated by muscle damage biomarkers.”

From study:Eccentric exercise per se does not affect muscle damage biomarkers: early and late phase adaptations

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design supports claim

Appropriate Language Strength

probability

Can suggest probability/likelihood

Assessment Explanation

The conclusion 'is the trigger' implies definitive causation beyond what the data can support. Blinding uncertainty and lack of mechanistic probes limit certainty.

More Accurate Statement

“Muscle unaccustomedness to high-intensity eccentric exercise is likely the primary trigger for muscle damage biomarkers, rather than the eccentric contraction itself.”

Evidence from Studies

Supporting (1)

Eccentric exercise per se does not affect muscle damage biomarkers: early and late phase adaptations

Randomized Controlled Trial

Human

2021 Feb

Your muscles get sore after doing a new kind of exercise, like lowering a weight slowly, but if you do it again and again, they stop getting damaged—even if you’re doing the exact same movement. The study shows it’s the newness, not the movement itself, that causes the damage.

Contradicting (0)

No contradicting evidence found

Source Study

Eccentric exercise per se does not affect muscle damage biomarkers: early and late phase adaptations

Score: 58

DOI: 10.1007/s00421-020-04528-w

Similar Assertions

It’s not the slow lowering that hurts—it’s that your muscles have never done it before. Once they’ve done it a few times, even doing it hard doesn’t hurt anymore.

91%

You don’t need to tear your muscles to make them stronger—your nervous system and muscle fibers can adapt and grow without damage.

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The first time you do hard eccentric exercises—like slowly lowering a heavy weight—your muscles get way more sore and damaged than if you just push the weight up.

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If you do hard eccentric exercises like lowering weights slowly once a week for 10 weeks, your muscles stop getting sore and damaged—even though the exercise is tough—because they get used to it.

77%

Even if you only train one way—like pushing weights up—your body still learns to handle hard eccentric movements without damage, suggesting the adaptation is whole-body, not just local.

77%