How Muscles Get Bigger When You Lift Weights
Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When you lift weights, your muscles get bigger because your body turns on special signals that help make more proteins and add more nuclei to muscle cells. Some signals turn on when you lift, and others turn off brakes that stop growth.
Surprising Findings
Muscle growth can occur even when mTORC1—the most famous muscle growth pathway—is inhibited.
For decades, mTORC1 was considered the primary driver of hypertrophy. This review shows multiple backup systems exist, challenging the dogma that 'mTORC1 = growth.'
Practical Takeaways
Progressively increase training volume or load every 2–4 weeks to activate satellite cells and ribosome biogenesis.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When you lift weights, your muscles get bigger because your body turns on special signals that help make more proteins and add more nuclei to muscle cells. Some signals turn on when you lift, and others turn off brakes that stop growth.
Surprising Findings
Muscle growth can occur even when mTORC1—the most famous muscle growth pathway—is inhibited.
For decades, mTORC1 was considered the primary driver of hypertrophy. This review shows multiple backup systems exist, challenging the dogma that 'mTORC1 = growth.'
Practical Takeaways
Progressively increase training volume or load every 2–4 weeks to activate satellite cells and ribosome biogenesis.
Publication
Journal
Physiological reviews
Year
2023
Authors
M. Roberts, J. McCarthy, T. Hornberger, S. Phillips, A. Mackey, G. Nader, M. Boppart, A. Kavazis, P. Reidy, R. Ogasawara, C. Libardi, C. Ugrinowitsch, F. Booth, K. Esser
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Claims (5)
To keep getting bigger and stronger muscles, you gotta slowly make your workouts harder over time—either lift heavier weights, do more reps, or do more sets.
When you lift weights, your muscles grow bigger because your body makes more tiny protein-making machines inside muscle cells, which helps build more of the proteins that make muscles strong and bulky.
When you lift heavy weights, your muscles get stretched and stressed just enough to tell your body to build more muscle fibers—this happens because a special molecular switch (mTORC1) turns on, making your muscles produce more proteins and the machinery needed to make them.
When your muscles get bigger from lifting weights, tiny repair cells called satellite cells stick themselves onto muscle fibers to give them extra nuclei—like adding more workers to a factory—so the muscle can keep growing big and strong.
When you lift weights, your muscles grow bigger not just through the usual pathway scientists know about, but also through other hidden backup systems in your cells that turn on genes and make more protein factories—all without needing the main growth switch.