In elite male weightlifters, 8 weeks of resistance training raises growth hormone levels regardless of how heavy the weights are, but does not change insulin or IGF-1 levels, suggesting that these...
Mechanism
Synthesis from 1 study
Elite weightlifters grow muscle not because their body releases more growth hormones like insulin or IGF-1, but because the physical strain of lifting—even light weights—turns on internal switches inside muscle cells that directly speed up protein building. This happens without needing hormonal...
Most probable mechanism
When elite weightlifters train with either light or heavy weights, the physical strain and burning sensation in their muscles trigger internal signals that turn on protein-making machinery directly inside muscle cells. This happens without needing a surge in growth hormones like insulin or IGF-1. Instead, the muscle cells use a backup system that activates key proteins to speed up the building of new muscle fibers, while also reducing damage and fatigue so they can train more often and recover faster.
Resistance training generates sustained mechanical tension and metabolic stress within skeletal muscle fibers, particularly during high-repetition efforts
This stress activates p70S6K1 through an AKT/mTOR-independent pathway, likely involving ERK/p90RSK or calcium-dependent signaling
Activated p70S6K1 phosphorylates ribosomal protein S6 and other targets to enhance ribosomal biogenesis and translation initiation
Resistance training simultaneously reduces phosphorylation of eukaryotic elongation factor 2 (eEF2), increasing its activity to accelerate ribosomal translocation during protein synthesis
The combined activation of p70S6K1 and dephosphorylation of eEF2 synergistically increase the rate of myofibrillar protein synthesis, leading to muscle hypertrophy
Reduced mechanical damage during training lowers the release of intracellular enzymes, decreasing inflammation and accelerating recovery, enabling higher training frequency
Growth hormone levels rise in response to training stress, but insulin and IGF-1 remain unchanged, indicating systemic anabolic signaling is not required for the observed muscle adaptations
Evidence from Studies
Supporting (1)
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Effects of Low-Load, High-Repetition Resistance Training on Maximum Muscle Strength and Muscle Damage in Elite Weightlifters: A Preliminary Study
Contradicting (0)
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