When people who don't normally lift weights do a tough arm exercise twice, four weeks apart, their biceps don't stretch as much the second time, even though they're trying just as hard.

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Evidence from Studies

Supporting (1)

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Reduced muscle lengthening during eccentric contractions as a mechanism underpinning the repeated-bout effect.

Randomized Controlled Trial

Human

2015 May 15

After doing hard arm exercises once, when the guys did them again four weeks later, their biceps didn’t stretch as much — meaning their muscles adapted and didn’t get stretched out as much during the workout, which helped them avoid damage.

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No contradicting evidence found

Source Study

Reduced muscle lengthening during eccentric contractions as a mechanism underpinning the repeated-bout effect.

Score: 37

DOI: 10.1152/ajpregu.00338.2014

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