Whether you rest 30 seconds or 2.5 minutes between sets of light weightlifting, you end up with about the same muscle growth and strength gains after 8 weeks.

Scientific Claim

In trained individuals performing low-load resistance training to failure, rest intervals of 30 seconds versus 150 seconds are associated with similar magnitudes of muscle hypertrophy and strength gains over 8 weeks.

Original Statement

“Both groups showed significant increases in triceps... thigh... and one-repetition maximum... In conclusion, our results suggest that acute hormonal responses, as well as chronic changes in muscle hypertrophy and strength in low-load training to failure are independent of the rest interval length.”

From study:Acute and Long-term Responses to Different Rest Intervals in Low-load Resistance Training

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The authors use 'independent of' and 'suggest' to imply no effect, but the study lacks power to detect small differences and lacks confirmed randomization. 'Associated with similar' is more accurate than 'independent of'.

Evidence from Studies

Supporting (1)

Acute and Long-term Responses to Different Rest Intervals in Low-load Resistance Training

Randomized Controlled Trial

Human

2017 Feb

People who lifted light weights to exhaustion with either 30 seconds or 2.5 minutes of rest between sets ended up gaining just as much muscle and strength after 8 weeks — so rest time didn’t matter much.

Contradicting (0)

No contradicting evidence found

Source Study

Acute and Long-term Responses to Different Rest Intervals in Low-load Resistance Training

Score: 38

DOI: 10.1055/s-0042-119204

Similar Assertions

If you're already someone who lifts weights, doing light weights twice a week until you can't do more reps can make your muscles bigger and stronger in just 8 weeks.

89%

Resting 30 seconds between sets of light weights builds your arm and leg muscles just as well as resting 2.5 minutes — at least in people who already train regularly.

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You can get stronger and bigger muscles by lifting light weights until you're exhausted — even if you never lift heavy, which challenges the old idea that heavy weights are required.

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Even though your body releases similar growth hormones after light workouts whether you rest a little or a lot, you still get stronger and bigger muscles either way.

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For people who already lift weights, it doesn’t matter much if you rest 30 seconds or 2.5 minutes between sets of light weights — you get the same muscle growth and strength gains either way.

87%