The official advice to rest 30–90 seconds between sets might be outdated — newer data suggest resting a bit longer (over a minute) could help your arms and legs grow a little better.
Scientific Claim
The National Strength and Conditioning Association’s recommendation of 30–90 second rest intervals for hypertrophy may not be optimal, as evidence suggests a small but consistent advantage for rest intervals longer than 60 seconds in limb muscles.
Original Statement
“These findings are inconsistent with recommendations from the National Strength and Conditioning Association, which prescribe relatively short rest periods (30–90 s) for hypertrophy-related goals. Thus, current guidelines regarding rest interval prescription for achieving muscular hypertrophy warrant reconsideration.”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
probability
Can suggest probability/likelihood
Assessment Explanation
The claim uses 'may not be optimal' and 'warrant reconsideration' — appropriate probabilistic language — and is directly supported by the authors’ conclusion and data trends.
Evidence from Studies
Supporting (1)
Give it a rest: a systematic review with Bayesian meta-analysis on the effect of inter-set rest interval duration on muscle hypertrophy
This study found that resting a bit longer than a minute between sets helps muscles grow slightly better in arms and legs, even though resting longer than 90 seconds doesn’t help much more. So the usual advice to rest 30–90 seconds might be improved by aiming for more than a minute.