The first time you stretch your biceps in each workout, it stretches the same amount—even if the second workout causes less damage overall.

Scientific Claim

The distal myotendinous junction displacement during the first contraction of each bout is not significantly different between the first and second eccentric exercise bouts in untrained men.

Original Statement

“No significant difference between bouts was evident in set 1 (ECC1: 8.2 ± 4.7 mm; ECC2: 8.5 ± 4.0 mm).”

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

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

definitive

Can make definitive causal claims

Assessment Explanation

This is a direct comparison of means with no causal claim. 'Not significantly different' is statistically accurate and appropriately phrased.

Evidence from Studies

Supporting (0)

No supporting evidence found

Contradicting (1)

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

Randomized Controlled Trial

Human

2015 May 15

The study found that after the first workout, muscles didn't stretch as much during the second workout — even on the very first rep — meaning the first reps of the second workout were already different from the first workout.

Source Study

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

Score: 37

DOI: 10.1152/ajpregu.00338.2014

Similar Assertions

The more the biceps stretched during the first tough workout, the more strength the person lost the next day.

80%

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.

77%