In young men with prior training experience, performing more sets of resistance exercises at a lighter weight led to a small but measurable increase in thigh muscle size over six weeks, while fewer...
Mechanism
Synthesis from 1 study
Lifting lighter weights for many reps makes muscle cells release more calcium, which triggers a signal that boosts production of non-muscle proteins inside the cell. These proteins fill up the space between muscle fibers, making the muscle look bigger without adding more contractile parts.
Most probable mechanism
Doing many repetitions with lighter weights causes muscle cells to release more calcium with each contraction. This calcium surge turns on a cellular signaling system that tells the cell to make more of certain non-muscle proteins, like those involved in energy production. These extra proteins swell the fluid-filled space inside the muscle cell, making the muscle appear larger without adding more contractile fibers.
Repeated high-repetition contractions during high-volume training increase intracellular calcium flux in muscle fibers
Elevated intracellular calcium activates MAPK signaling pathways (e.g., ERK1/2)
Activated MAPK signaling upregulates translational machinery for non-myofibrillar proteins (e.g., metabolic enzymes, sarcoplasmic proteins)
Increased synthesis of non-myofibrillar proteins leads to accumulation of sarcoplasmic components without proportional myofibrillar growth
Evidence from Studies
Supporting (1)
Community contributions welcome
Effects of High-Volume Versus High-Load Resistance Training on Skeletal Muscle Growth and Molecular Adaptations
Contradicting (0)
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