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.
Scientific Claim
In trained individuals, low-load resistance training to failure with 30-second rest intervals produces comparable muscle hypertrophy in the triceps and thighs to training with 150-second rest intervals over an 8-week period.
Original Statement
“Both groups showed significant increases in triceps (S: 9.8±8.8%, L: 10.6±9.6%, p<0.05) and thigh (S: 5.7±4.7%, L: 8.3±6.4%, p<0.05) cross-sectional area.”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The claim implies equivalence, but the study lacks statistical power to confirm no difference. 'Comparable' is acceptable, but the phrasing implies causation.
More Accurate Statement
“In trained individuals, low-load resistance training to failure with 30-second rest intervals is associated with comparable muscle hypertrophy in the triceps and thighs to training with 150-second rest intervals over an 8-week period.”
Evidence from Studies
Supporting (1)
Acute and Long-term Responses to Different Rest Intervals in Low-load Resistance Training
People who lifted light weights to exhaustion with either 30-second or 150-second breaks between sets both gained about the same amount of muscle in their arms and thighs after 8 weeks — so rest time didn’t matter much.