The rest period between sets should be adapted to the goal and type of exercise, rather than being rigidly timed.

noli's read

Modern sports science research indicates that rest between sets is a factor for modulating total volume rather than an absolute rule. Studies (meta-analyses and randomized controlled trials) show that longer rest periods (2-3 minutes) often favor hypertrophy for compound exercises by allowing for better recovery and, therefore, a higher volume of work (sets × repetitions × load). Conversely, short rest periods (30-90 seconds) can be effective for certain isolation exercises or when saving time is a priority, provided that intensity remains close to failure. The idea that very short rest periods are strictly superior for muscle growth due to acute hormonal responses is now considered largely exaggerated, with overall volume remaining the primary driver. It is therefore common to recommend adjusting rest based on perceived fatigue to ensure that each set is stimulating.

the sources

No named source held this one up — that absence is part of the verdict.