When lifting weights to exhaustion with only one minute of rest between sets, doing six sets instead of four does not lead to more muscle growth.
Mechanism
Synthesis from 1 study
When you lift weights to failure with only one minute of rest, your muscles get the maximum growth signal they can handle — adding more sets doesn’t give you more signal. Studies show that whether you do four or six sets under these conditions, your muscles grow the same amount because the...
Most probable mechanism
When you lift weights to failure with only one minute of rest between sets, your muscles generate enough tension and metabolic stress to fully turn on the growth signals — adding more sets doesn’t turn them up any further. Studies show that even when people did double the number of sets with very short rest, their muscles grew just as much as with fewer sets, because the key signals for growth (like mTOR) had already reached their maximum activation level.
Resistance exercise to muscular failure generates sufficient mechanical tension and metabolite accumulation (lactate, H+, Pi) to maximally activate mTORC1 signaling pathways in muscle fibers, regardless of whether four or six sets are performed under one-minute rest intervals.
mTORC1 activation reaches a threshold beyond which further increases in set volume do not enhance ribosomal biogenesis or translation initiation, limiting additional myofibrillar protein synthesis even when total training volume increases.
Saturation of anabolic signaling results in identical net increases in myofibrillar protein content and muscle fiber cross-sectional area, regardless of whether four or six sets are performed under short rest conditions.
Less supported by current evidence, but not ruled out
When training to failure with short rest, the nervous system may already be working at its maximum capacity to recruit muscle fibers — adding more sets doesn’t recruit more fibers because the body can’t drive them harder than it already is.
Repeated sets to failure under short rest intervals lead to maximal recruitment of high-threshold motor units, consistent with Henneman’s size principle, with no further recruitment possible beyond a certain volume.
Neural drive, including motor unit firing rate and corticospinal excitability, plateaus under high-frequency, failure-based protocols, preventing additional muscle fiber activation even with increased set count.
Evidence from Studies
Supporting (1)
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Effect of resistance training programs differing in set structure on muscular hypertrophy and performance in untrained young men
Contradicting (0)
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