Which is true of the high levels of mechanical stretch across the muscle membrane during resistance training?

• A. They reduce muscle strength
• B. They cause muscle atrophy
• C. They result in muscle hypertrophy
• D. They have no effect on muscle size

Answer: (C)

High levels of mechanical stretch during resistance training act as a potent growth signal for muscle, triggering mechanotransduction that pushes the muscle toward growth. The tension sensed by receptors at the muscle cell membrane activates anabolic signaling—most notably the mTOR pathway—leading to increased ribosome production and protein synthesis, particularly of myofibrillar proteins. Satellite cells may also be recruited to support the growing fiber, expanding its cross-sectional area. Over weeks of repeated overload with adequate protein and energy intake, this process results in hypertrophy, meaning the muscle fibers increase in size and strength. This is in contrast to disuse or insufficient stimulus, which can lead to atrophy or minimal size change.