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.

Scientific Claim

In untrained men, the magnitude of muscle damage after eccentric exercise is not determined by the eccentric contraction itself, but by the novelty of the stimulus, as damage is absent after repeated exposure despite identical mechanical work.

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, but the study does not isolate unaccustomedness from other variables (e.g., neural adaptation, connective tissue remodeling).

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

When untrained men did eccentric exercise for the first time, their muscles got sore and damaged—but after doing it nine more times with the same effort, their muscles stopped getting damaged, proving it was the newness, not the exercise type, that caused 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 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.

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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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Your body learns to handle hard eccentric exercises so well that after 10 weeks, it doesn’t even react as if it’s damaged—even though you’re still doing the same hard movements.

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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.

78%