In people who already train regularly, 8 weeks of weight training causes a small increase in muscle size that is often too small to measure reliably, making it hard to tell which training methods are...
Mechanism
Synthesis from 4 studies
Trained muscles don't grow much from lifting weights because their protein-building system is already running near full capacity. The extra stress from training only bumps up protein production a tiny bit, so the muscle gets only slightly bigger — too small to measure reliably, making it impossible...
Most probable mechanism
When trained people lift weights, the mechanical stress from the exercise turns on a molecular switch in muscle cells that tells them to build more contractile proteins. But because their muscles are already adapted, this switch only turns on a little bit, so the muscles grow very slightly. This tiny growth is often too small to measure accurately, making it hard to tell if one training method is better than another.
Mechanical tension from resistance training activates mechanosensitive proteins in skeletal muscle fibers
Mechanotransduction signals converge on the mTORC1 complex, triggering its activation
Activated mTORC1 phosphorylates p70S6K, enhancing ribosomal biogenesis and translation initiation
Increased translational capacity elevates myofibrillar protein synthesis rates
Net protein accretion over time results in minimal myofiber hypertrophy, often within the margin of measurement error
Evidence from Studies
Supporting (4)
Community contributions welcome
Higher resistance training volume offsets muscle hypertrophy non-responsiveness in older individuals.
Effect of resistance training to muscle failure vs non-failure on strength, hypertrophy and muscle architecture in trained individuals
Molecular signatures underlying heterogenous hypertrophy responsiveness to resistance training in older men and women: a within-subject design.
Knee flexion range of motion does not influence muscle hypertrophy of the quadriceps femoris during leg press training in resistance-trained individuals
Contradicting (0)
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