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.
Scientific Claim
In trained individuals, low-load resistance training to failure with either 30-second or 150-second rest intervals produces similar acute hormonal responses and chronic muscle and strength adaptations over 8 weeks.
Original Statement
“Both groups showed significant (p<0.05) increases in growth hormone and insulin-like growth factor 1 immediately post-workout... 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.”
Evidence Quality Assessment
Claim Status
overstated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The conclusion uses 'independent of' and 'suggest' to imply no effect, but the study lacks randomization and power to confirm equivalence. 'Associated with similar' is the only appropriate phrasing.
More Accurate Statement
“In trained individuals, low-load resistance training to failure with either 30-second or 150-second rest intervals is associated with similar acute hormonal responses and chronic muscle and strength adaptations over 8 weeks.”
Evidence from Studies
Supporting (1)
Acute and Long-term Responses to Different Rest Intervals in Low-load Resistance Training
The study found that whether you rest 30 seconds or 2.5 minutes between sets during light weight training to exhaustion, you get the same muscle growth and strength gains over 8 weeks, and your body releases similar hormones after each workout.