In trained young men, two different types of weight training—high-volume and high-load—result in the same rate of muscle protein synthesis after six weeks, meaning neither style leads to greater...
Mechanism
Synthesis from 1 study
Both heavy lifting and high-rep training make your muscles build the same amount of contractile proteins because they both hit the same molecular trigger for protein growth. Even though they feel different, your muscles respond to the total workload in a way that equalizes the growth of the...
Most probable mechanism
When you lift heavy weights or do many reps with lighter weights, your muscle cells sense the total amount of work done and turn on the same molecular switch to build contractile proteins. Even though the way you lift is different, the overall stress on the muscle fibers triggers the same level of protein-building signals, so both methods grow the contractile parts of the muscle at the same rate.
Resistance training, regardless of load or volume, induces mechanical tension and metabolic stress in muscle fibers during contractions
Mechanical tension and metabolic stress activate the mTORC1 signaling pathway in muscle cells
mTORC1 activation increases the translation of mRNA into myofibrillar proteins such as actin and myosin
Integrated myofibrillar protein synthesis rates remain similar between high-volume and high-load conditions because mTORC1 activation reaches a comparable threshold in both
Less supported by current evidence, but not ruled out
High-volume and high-load training might use different molecular signals to tell the muscle to grow, but both end up turning on the same amount of contractile protein production, like two different roads leading to the same destination.
High-volume training increases intracellular calcium flux, activating MAPK signaling pathways
High-load training increases mechanical tension, preferentially activating mTORC1 signaling
MAPK signaling drives synthesis of non-myofibrillar proteins, while mTORC1 drives myofibrillar protein synthesis
Despite different upstream signals, myofibrillar protein synthesis rates are equal because mTORC1 activation is sufficient and not suppressed by MAPK activity
Evidence from Studies
Supporting (1)
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Effects of High-Volume Versus High-Load Resistance Training on Skeletal Muscle Growth and Molecular Adaptations
Contradicting (0)
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