The total amount of effective resistance exercise performed for each muscle group in a week is the most important factor in determining how much muscle size increases.
Mechanism
Synthesis from 4 studies
More workouts mean your muscles get squeezed and stretched more, which tells them to build more protein and grow bigger. Even if your body gets used to it, doing enough over the week still pushes growth because the signals to build muscle keep adding up.
Most probable mechanism
When you do more reps and sets, your muscle fibers get stretched and squeezed harder, which sends signals inside the cells to start building more muscle proteins. The more you do this over the week, the more your muscles grow.
Increased mechanical load during resistance exercises stretches muscle fibers and generates tension across sarcomeres
Mechanical tension and metabolic byproducts (e.g., lactate, ROS) activate intracellular signaling pathways including mTORC1
mTORC1 activation increases ribosomal biogenesis and translation initiation, elevating myofibrillar protein synthesis rates
Cumulative protein synthesis over multiple sessions leads to net accretion of contractile proteins and muscle fiber enlargement
Less supported by current evidence, but not ruled out
Doing more workouts may also help muscles grow by slowing down how fast the body breaks them down, letting more protein stick around.
Repeated mechanical stress from high-volume training downregulates expression of atrophy-related E3 ubiquitin ligases (e.g., MuRF1, MAFbx)
Reduced proteasomal degradation allows net accumulation of myofibrillar proteins despite ongoing turnover
Evidence from Studies
Supporting (2)
Community contributions welcome
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 (2)
Community contributions welcome
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.