Hormonal
Repeated bouts of mechanical overload (resistance training) induce skeletal muscle hypertrophy primarily through transient increases in mTORC1 signaling, which elevates muscle protein synthesis rates, alongside expanded translational capacity via ribosome biogenesis and increased satellite cell abundance/myonuclear accretion.
To build muscle, you must consistently apply mechanical overload (resistance training) to your muscles. This triggers internal cellular signals (mTORC1) that increase protein synthesis and add new nuclei to muscle fibers. Focus on progressive resistance training over 8-16 weeks to achieve significant mass gains (5-20%). Do not rely solely on hormones or 'pumps'; the mechanical stimulus is the primary driver.
Studies in animals and humans suggest that mechanical overload (e.g., resistance training) best achieves skeletal muscle hypertrophy. Bouts of mechanical overload induce transient increases in mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling leading to elevations in muscle protein synthesis rates. With repeated bouts of mechanical overload, these events contribute to skeletal muscle hypertrophy. An expansion in translational capacity through ribosome biogenesis and increases in satellite cell abundance and myonuclear accretion also contribute to skeletal muscle hypertrophy following days to weeks of repeated mechanical overload bouts.
Why this rating
This is a comprehensive review in Physiological Reviews by multiple experts, synthesizing decades of rodent and human studies.
Source
Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions
Michael D. Roberts et al. · Physiological Reviews · 2023
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