Even light weightlifting until exhaustion makes your body release hormones that are linked to muscle growth, no matter how long you rest between sets.

Scientific Claim

A single session of low-load resistance training to failure at 40% one-repetition maximum, with either 30-second or 150-second rest intervals, is associated with significant immediate post-exercise increases in growth hormone and insulin-like growth factor 1 in trained individuals.

Original Statement

“Both groups showed significant (p<0.05) increases in growth hormone and insulin-like growth factor 1 immediately post-workout.”

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 study measured hormone changes after a single bout, but without randomization or control for confounders, it cannot prove the rest interval caused the response. 'Increases' implies causation.

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

The study found that even a light workout to exhaustion, whether you rest 30 seconds or 2.5 minutes between sets, causes a big spike in two important muscle-growth hormones right after exercising.

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

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.

84%

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.

78%

Whether you rest a short or long time between light weightlifting sets, your body releases about the same amount of growth-related hormones right after the workout.

76%

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.

76%

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.

75%