Some people don't gain muscle with certain workout volumes, but they might grow a lot when switching to a different amount—meaning everyone might respond best to their own 'sweet spot' for lifting...
Mechanism
Synthesis from 2 studies
When people do more sets of weight exercises, the stress on their muscles turns on a protein switch called mTOR, which tells the muscle to make more building blocks — this only happens if they do enough sets, as shown in 10.1152/japplphysiol.00670.2023. People who didn’t grow with light workouts...
Most probable mechanism
When someone does more sets of resistance exercises, the mechanical stress on their muscles turns on a molecular switch called mTOR, which then activates p70S6K — this helps the muscle make more proteins, leading to growth. People who don’t grow with low volume often respond when volume is increased, as shown in 10.1152/japplphysiol.00670.2023, because their muscles were previously under-stimulated and only activate this pathway when volume reaches a personal threshold.
Mechanical tension from increased resistance training volume activates mechanosensitive structures in skeletal muscle fibers, initiating intracellular signaling cascades — supported by 10.1152/japplphysiol.00670.2023, which links volume to mTOR pathway activation independent of intensity or muscle action.
Mechanotransduction signals converge on the mTORC1 complex, promoting its phosphorylation and activation — supported by 10.1152/japplphysiol.00670.2023 through indirect evidence showing volume-dependent increases in p70S6K, a direct downstream target of mTORC1.
Activated p70S6K phosphorylates ribosomal protein S6, enhancing ribosome biogenesis and translation initiation of muscle-specific proteins — supported by 10.1152/japplphysiol.00670.2023, which directly associates higher volume with increased p70S6K activation.
Increased translational capacity elevates myofibrillar protein synthesis rates, creating a net positive protein balance over time — supported by 10.1152/japplphysiol.00670.2023, which shows that only increased volume, not other variables, acutely boosts myofibrillar protein synthesis.
Sustained protein synthesis over training weeks leads to myofiber hypertrophy and increased muscle cross-sectional area, particularly in individuals previously nonresponsive to lower volumes — directly observed in 10.1152/japplphysiol.00670.2023, where nonresponders to one set achieved significant quadriceps growth only after switching to four sets.
Evidence from Studies
Supporting (2)
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Higher resistance training volume offsets muscle hypertrophy non-responsiveness in older individuals.
Muscle Hypertrophy Response Is Affected by Previous Resistance Training Volume in Trained Individuals
Contradicting (0)
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