Resting longer between sets lets you lift more total weight, which makes muscles grow bigger.
Scientific Claim
Increasing rest intervals between sets enhances total training tonnage, which amplifies mechanical tension and thereby increases skeletal muscle hypertrophy.
Original Statement
“In all of these cases we see that the main benefit of spreading the volume out more across the week, or across different days, or across the same session is that you increase rest times and therefore you increase total training tonnage, and that increase in training tonnage basically makes you accumulate more mechanical tension on the muscles, and that is what makes you gain more muscle mass.”
Context Details
Domain
exercise
Population
human
Subject
increased rest intervals
Action
enhance
Target
total training tonnage and mechanical tension
Intervention Details
Evidence from Studies
Supporting (1)
Increased Neuromuscular Activity, Force Output, and Resistance Exercise Volume When Using 5-Minute Compared with 2-Minute Rest Intervals Between the Sets
This study found that taking longer breaks (5 minutes) between weightlifting sets lets you lift more total weight and feel less tired than taking short breaks (2 minutes), which means you can work your muscles harder — and that’s how muscles grow bigger.
Contradicting (2)
Give it a rest: a systematic review with Bayesian meta-analysis on the effect of inter-set rest interval duration on muscle hypertrophy
The study found that resting longer between sets doesn’t make your muscles grow much more than resting briefly — and it’s not because you’re lifting more weight overall. So, the idea that longer rests boost muscle growth by letting you lift more doesn’t hold up.
The study found that whether you rest 20 seconds or 2 minutes between sets, you get the same muscle growth as long as you do the same total amount of work — so longer rests don’t magically make you bigger.