Over eight weeks, beginners who do biceps curls and triceps pushdowns with either strict technique or using momentum both experience measurable increases in muscle size.
Mechanism
Synthesis from 1 study
Whether you lift slowly and controlled or use a little swing, your muscles still get pulled hard enough to signal the body to build more muscle. The key isn't how clean the movement is — it's that the muscle fibers are being stretched and loaded, which tells them to grow bigger over time.
Most probable mechanism
When muscles are stretched and pulled during exercise, even if the movement is sloppy or uses momentum, the fibers still get tugged hard enough to send signals that tell the body to build more muscle protein, leading to growth over time.
Muscle fibers experience mechanical tension during both strict and momentum-assisted contractions due to load-induced stretch and force generation.
This tension activates signaling pathways within muscle cells, particularly the mTOR pathway, which senses physical stress and initiates protein synthesis.
Increased rates of muscle protein synthesis exceed breakdown, resulting in net accumulation of contractile proteins and muscle fiber enlargement.
Evidence from Studies
Supporting (1)
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Do Cheaters Prosper? Effect of Externally Supplied Momentum During Resistance Training on Measures of Upper Body Muscle Hypertrophy
Contradicting (0)
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Gold Standard Evidence Needed
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