For young men who regularly lift weights, the number of sets taken to muscular failure may better predict muscle growth than the total weight lifted or the number of repetitions performed, as long as...
Mechanism
Synthesis from 1 study
When you train until you can't do another rep, your body uses nearly all your muscle fibers, no matter how light the weight. This creates strong forces inside the muscle that tell it to grow. Even if one person lifts heavy and another lifts light, if both push to exhaustion, their muscles grow...
Most probable mechanism
When you lift weights until you can't do another rep, your body forces more muscle fibers to work, even if the weight is light. This extra effort creates strong pulling forces inside the muscle, which tells the muscle to build more protein and get bigger. It doesn't matter as much how heavy the weight is — what matters is pushing until you're completely tired.
Resistance training to muscular failure recruits high-threshold motor units, activating a larger proportion of muscle fibers regardless of load intensity
Mechanical tension generated by activated muscle fibers triggers intracellular signaling pathways, including mTOR, that increase muscle protein synthesis
Sustained net positive muscle protein balance leads to myofibrillar accretion and enlargement of muscle fibers
Less supported by current evidence, but not ruled out
When blood flow is partially restricted during exercise, waste products build up in the muscle, causing it to swell. This swelling and chemical environment activate signals that tell the muscle to grow, even if the weight is light.
External pressure applied during resistance training partially restricts venous outflow, causing metabolite accumulation (e.g., lactate, hydrogen ions, inorganic phosphate)
Metabolite accumulation and cellular swelling activate anabolic signaling pathways such as mTOR and MAPK, and increase satellite cell activity
Enhanced anabolic signaling and satellite cell recruitment lead to increased muscle protein synthesis and fiber hypertrophy
Evidence from Studies
Supporting (1)
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Contradicting (0)
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